Synthesizing single-phase β-FeSi2 via ion beam irradiations of Fe/Si bilayers

International Nuclear Information System (INIS)

Milosavljevic, M.; Dhar, S.; Schaaf, P.; Bibic, N.; Lieb, K.P.

2001-01-01

This paper presents results on the direct synthesis of the β-FeSi 2 phase by ion beam mixing of Fe/Si bilayers with Xe ions. The influence of the substrate temperature, ion fluence and energy on the growth of this phase was investigated using Rutherford backscattering (RBS), X-ray diffraction (XRD) and conversion electron Moessbauer spectroscopy (CEMS). Complete growth of single-phase β-FeSi 2 was achieved by 205 keV Xe ion irradiation to a fluence of 2x10 16 ions/cm 2 at 600 deg. C. We propose a two-step reaction mechanism involving thermal and ion beam energy deposition

Ion-irradiation induced chemical ordering of FePt and FePtAu nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Seetala, Naidu V. [Department of Physics, Grambling State University, RWE Jones Drive, Carver Hall 81, Grambling, LA 71245 (United States)]. E-mail: naidusv@gram.edu; Harrell, J.W. [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Lawson, Jeremy [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Nikles, David E. [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Williams, John R. [Department of Physics, Auburn University, Auburn, AL 36849 (United States); Isaacs-Smith, Tamara [Department of Physics, Auburn University, Auburn, AL 36849 (United States)

2005-12-15

We have studied the effect of ion-beam irradiation on reducing the ordering temperature of FePt and FePtAu nanoparticles. FePt and FePt(Au14%) 4 nm particles dispersed on a Si-substrate were irradiated by 300 keV Al-ions with a dose of 1 x 10{sup 16} ions/cm{sup 2} at 43 {sup o}C using a water-cooled flange in order to minimize the vacancy migration and voids formation within the collision cascades. Partial chemical ordering has been observed in as-irradiated particles with coercivity of 60-130 Oe. Post-irradiation annealing at 220 {sup o}C enhanced chemical ordering in FePt nanoparticles with coercivity of 3500 Oe, magnetic anisotropy of 1.5 x 10{sup 7} erg/cc, and thermal stability factor of 130. A much higher 375 {sup o}C post-irradiation annealing was required in FePtAu, presumably because Au atoms were trapped at Fe/Pt lattice sites at lower temperatures. As the annealing temperature increased, anomalous features in the magnetization reversal curves were observed that disappeared at higher annealing temperatures.

Influence of ruthenium ions on the precipitation of α-FeOOH, α-Fe2O3 and Fe3O4 in highly alkaline media

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar

2006-01-01

The influence of ruthenium ions on the precipitation of goethite (α-FeOOH), α-Fe 2 O 3 and Fe 3 O 4 in highly alkaline media was investigated by 57 Fe Moessbauer and FT-IR spectroscopies, thermal field emission scanning electron microscope (FE SEM) and EDS. The presence of Ru-dopant strongly affected the precipitation of α-FeOOH at highly alkaline pH, i.e. the formation of α-Fe 2 O 3 was also noticed. A decrease of hyperfine magnetic field (HMF) at RT from 35.1 T (undoped α-FeOOH) to 31.3 T for sample with [Ru]/([Ru] + [Fe]) = 0.0196 was assigned to the incorporation of ruthenium ions into the α-FeOOH structure. Moessbauer spectroscopy showed the formation of stoichiometric Fe 3 O 4 for [Ru]/([Ru] + [Fe]) = 0.0291-0.0909. α-Fe 2 O 3 and Fe 3 O 4 did not show a tendency to the formation of solid solutions with ruthenium ions. FE SEM observations of the samples showed that reference α-FeOOH sample contained acicular particles of good uniformity, which increased the length up to ∼5 times with increase of concentration of ruthenium ions. On the other hand, large octahedral Fe 3 O 4 crystals (particles) were associated with small particles of ruthenium (hydrous) oxide with a size in the range ∼100 nm or less. A possible catalytic action of ruthenium that created reduction conditions for Fe 3+ ions and formation of Fe 2+ ions for precipitation of Fe 3 O 4 was discussed

Thermophysical lesions caused by HZE particles

International Nuclear Information System (INIS)

Tobias, C.A.; Malachowski, M.; Nelson, A.; Philpott, D.E.

1980-01-01

This paper deals with a type of damage caused by heavy particles that may occur in subcellular structures. These lesions are called thermophysical radiation injury and are similar to damage produced in solids by HZE particles. This chapter summarizes some of the experimental evidence for the presence of these lesions in certain mammalian tissues including the retina, brain, cornea, lens of mice and seeds of corn. Of all tissues examined, only the cornea exhibited a type of lesion which would fulfill the criteria of thermophysical lesions

Biological effects of single HZE-particles of the cosmic radiation: Free Flyer Biostack

International Nuclear Information System (INIS)

1989-01-01

The Free Flyer Biostack is designed as a passive, longer term experiment for investigations into the dosimetry of cosmic HZE particles (high-charge energetic particles), the effects of single HZE particles on isolated biological samples, and the synergistic effects of conditions in space, as e.g. zero gravity and presence of a permanent, weakly ionizing component of the cosmic radiation. For the experiments summarized in this project report, the AgCl detector type developed in Frankfurt has been used, consisting of monocrystalline AgCl films, about 130-150 μm thick, and doped with 5000 ppm of Cd. (DG) With 9 figs [de

A pulse synthesis of beta-FeSi sub 2 layers on silicon implanted with Fe sup + ions

CERN Document Server

Batalov, R I; Terukov, E I; Kudoyarova, V K; Weiser, G; Kuehne, H

2001-01-01

The synthesis of thin beta-FeSi sub 2 films was performed by means of the Fe sup + ion implantation into Si (100) and the following nanosecond pulsed ion treatment of implanted layer. Using the beta-FeSi sub 2 beta-FeSi sub 2 e X-ray diffraction it is shown that the pulsed ion treatment results in the generation of the mixture of two phases: FeSi and beta-FeSi sub 2 with stressed crystal lattices. The following short-time annealing leads to the total transformation of the FeSi phase into the beta-FeSi sub 2 one. The Raman scattering data prove the generation of the beta-FeSi sub 2 at the high degree of the silicon crystallinity. The experimental results of the optical absorption testify to the formation of beta-FeSi sub 2 layers and precipitates with the straight-band structure. The photoluminescence signal at lambda approx = 1.56 mu m observes up to 210 K

Heavy ion mutagenesis: linear energy transfer effects and genetic linkage

Science.gov (United States)

Kronenberg, A.; Gauny, S.; Criddle, K.; Vannais, D.; Ueno, A.; Kraemer, S.; Waldren, C. A.; Chatterjee, A. (Principal Investigator)

1995-01-01

We have characterized a series of 69 independent mutants at the endogenous hprt locus of human TK6 lymphoblasts and over 200 independent S1-deficient mutants of the human x hamster hybrid cell line AL arising spontaneously or following low-fluence exposures to densely ionizing Fe ions (600 MeV/amu, linear energy transfer = 190 keV/microns). We find that large deletions are common. The entire hprt gene (> 44 kb) was missing in 19/39 Fe-induced mutants, while only 2/30 spontaneous mutants lost the entire hprt coding sequence. When the gene of interest (S1 locus = M1C1 gene) is located on a nonessential human chromosome 11, multilocus deletions of several million base pairs are observed frequently. The S1 mutation frequency is more than 50-fold greater than the frequency of hprt mutants in the same cells. Taken together, these results suggest that low-fluence exposures to Fe ions are often cytotoxic due to their ability to create multilocus deletions that may often include the loss of essential genes. In addition, the tumorigenic potential of these HZE heavy ions may be due to the high potential for loss of tumor suppressor genes. The relative insensitivity of the hprt locus to mutation is likely due to tight linkage to a gene that is required for viability.

Mutagenesis in human cells with accelerated H and Fe ions

Science.gov (United States)

Kronenberg, Amy

1994-01-01

The overall goals of this research were to determine the risks of mutation induction and the spectra of mutations induced by energetic protons and iron ions at two loci in human lymphoid cells. During the three year grant period the research has focused in three major areas: (1) the acquisition of sufficient statistics for human TK6 cell mutation experiments using Fe ions (400 MeV/amu), Fe ions (600 MeV/amu) and protons (250 MeV/amu); (2) collection of thymidine kinase- deficient (tk) mutants or hypoxanthine phosphoribosyltransferase deficient (hprt) mutants induced by either Fe 400 MeV/amu, Fe 600 MeV/amu, or H 250 MeV/amu for subsequent molecular analysis; and (3) molecular characterization of mutants isolated after exposure to Fe ions (600 MeV/amu). As a result of the shutdown of the BEVALAC heavy ion accelerator in December 1992, efforts were rearranged somewhat in time to complete our dose-response studies and to complete mutant collections in particular for the Fe ion beams prior to the shutdown. These goals have been achieved. A major effort was placed on collection, re-screening, and archiving of 3 different series of mutants for the various particle beam exposures: tk-ng mutants, tk-sg mutants, and hprt-deficient mutants. Where possible, groups of mutants were isolated for several particle fluences. Comparative analysis of mutation spectra has occured with characterization of the mutation spectrum for hprt-deficient mutants obtained after exposure of TK6 cells to Fe ions (600 MeV/amu) and a series of spontaneous mutants.

Biophysical aspects of heavy ion interactions in matter

International Nuclear Information System (INIS)

Schimmerling, W.; Wong, M.; Ludewigt, B.; Phillips, M.; Alpen, E.L.; Powers-Risius, P.; DeGuzman, R.J.; Townsend, L.W.; Wilson, J.W.

1989-01-01

The biological effects of high energy, high charge nuclei (HZE particles) occupy a central role in the management of space radiation hazards due to galactic cosmic rays. For the energy range of interest, the mean free path for nuclear interactions of these heavy ions is comparable to the thickness of the material traversed, and a significant fraction of stopping particles will undergo a nuclear reaction with the nuclei of the stopping material. Transport methods for HZE particles are dependent on models of the interaction of man-made systems with the space environment to an even greater extent than methods used for other types of radiation. Hence, there is a major need to validate these transport codes by comparison with experimental data. The basic physical properties of HZE particles will be reviewed and illustrated with the results of nuclear fragmentation experiments performed with 670A MeV neon ions incident on a water absorber and with measurements of multiple Coulomb scattering of uranium beams in copper. Finally, the extent to which physical measurements yield radiobiological predictions is illustrated for the example of neon

56Fe particle exposure results in a long-lasting increase in a cellular index of genomic instability and transiently suppresses adult hippocampal neurogenesis in vivo

Science.gov (United States)

DeCarolis, Nathan A.; Rivera, Phillip D.; Ahn, Francisca; Amaral, Wellington Z.; LeBlanc, Junie A.; Malhotra, Shveta; Shih, Hung-Ying; Petrik, David; Melvin, Neal R.; Chen, Benjamin P. C.; Eisch, Amelia J.

2014-07-01

The high-LET HZE particles from galactic cosmic radiation pose tremendous health risks to astronauts, as they may incur sub-threshold brain injury or maladaptations that may lead to cognitive impairment. The health effects of HZE particles are difficult to predict and unfeasible to prevent. This underscores the importance of estimating radiation risks to the central nervous system as a whole as well as to specific brain regions like the hippocampus, which is central to learning and memory. Given that neurogenesis in the hippocampus has been linked to learning and memory, we investigated the response and recovery of neurogenesis and neural stem cells in the adult mouse hippocampal dentate gyrus after HZE particle exposure using two nestin transgenic reporter mouse lines to label and track radial glia stem cells (Nestin-GFP and Nestin-CreERT2/R26R:YFP mice, respectively). Mice were subjected to 56Fe particle exposure (0 or 1 Gy, at either 300 or 1000 MeV/n) and brains were harvested at early (24 h), intermediate (7 d), and/or long time points (2-3 mo) post-irradiation. 56Fe particle exposure resulted in a robust increase in 53BP1+ foci at both the intermediate and long time points post-irradiation, suggesting long-term genomic instability in the brain. However, 56Fe particle exposure only produced a transient decrease in immature neuron number at the intermediate time point, with no significant decrease at the long time point post-irradiation. 56Fe particle exposure similarly produced a transient decrease in dividing progenitors, with fewer progenitors labeled at the early time point but equal number labeled at the intermediate time point, suggesting a recovery of neurogenesis. Notably, 56Fe particle exposure did not change the total number of nestin-expressing neural stem cells. These results highlight that despite the persistence of an index of genomic instability, 56Fe particle-induced deficits in adult hippocampal neurogenesis may be transient. These data support

Transient field measurements on 56Fe- and 80Se-ions using segmented Fe-layers

International Nuclear Information System (INIS)

Busch, H.; Kremeyer, S.; Meens, A.; Maier-Komor, P.

1996-01-01

Measurements of transient magnetic fields (TF) were performed on swift heavy ions of 56 Fe and 80 Se, with Coulomb excitation of their first 2 + state as probe, traversing thin Fe layers with segmented and unsegmented structures. The 50 μm x 50 μm squares of the segments were accomplished applying the techniques of photolithography and ion etching. The magnitude of the TF deduced clearly shows that by segmentation of the targets the ion beam induced attenuations can be eliminated. This finding has direct applications to g-factor measurements. (orig.)

Fe(III) and Fe(II) ions different effects on Enterococcus hirae cell growth and membrane-associated ATPase activity

Energy Technology Data Exchange (ETDEWEB)

Vardanyan, Zaruhi [Department of Biophysics of the Biology Faculty, Yerevan State University, 1 A. Manoukian Str., 0025 Yerevan (Armenia); Trchounian, Armen, E-mail: trchounian@ysu.am [Department of Biophysics of the Biology Faculty, Yerevan State University, 1 A. Manoukian Str., 0025 Yerevan (Armenia)

2012-01-06

Highlights: Black-Right-Pointing-Pointer Fe{sup 3+} stimulates but Fe{sup 2+} suppresses Enterococcus hirae wild-type and atpD mutant growth. Black-Right-Pointing-Pointer Fe ions change oxidation-reduction potential drop during cell growth. Black-Right-Pointing-Pointer Fe{sup 3+} and Fe{sup 2+} have opposite effects on a membrane-associated ATPase activity. Black-Right-Pointing-Pointer These effects are either in the presence of F{sub 0}F{sub 1} inhibitor or non-functional F{sub 0}F{sub 1}. Black-Right-Pointing-Pointer Fe ions decrease protons and coupled potassium ions fluxes across the membrane. -- Abstract: Enterococcus hirae is able to grow under anaerobic conditions during glucose fermentation (pH 8.0) which is accompanied by acidification of the medium and drop in its oxidation-reduction potential (E{sub h}) from positive values to negative ones (down to {approx}-200 mV). In this study, iron (III) ions (Fe{sup 3+}) have been shown to affect bacterial growth in a concentration-dependent manner (within the range of 0.05-2 mM) by decreasing lag phase duration and increasing specific growth rate. While iron(II) ions (Fe{sup 2+}) had opposite effects which were reflected by suppressing bacterial growth. These ions also affected the changes in E{sub h} values during bacterial growth. It was revealed that ATPase activity with and without N,N Prime -dicyclohexylcarbodiimide (DCCD), an inhibitor of the F{sub 0}F{sub 1}-ATPase, increased in the presence of even low Fe{sup 3+} concentration (0.05 mM) but decreased in the presence of Fe{sup 2+}. It was established that Fe{sup 3+} and Fe{sup 2+} both significantly inhibited the proton-potassium exchange of bacteria, but stronger effects were in the case of Fe{sup 2+} with DCCD. Such results were observed with both wild-type ATCC9790 and atpD mutant (with defective F{sub 0}F{sub 1}) MS116 strains but they were different with Fe{sup 3+} and Fe{sup 2+}. It is suggested that the effects of Fe{sup 3+} might be due to

Damage induced by helium ion irradiation in Fe-based metallic glass

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaonan; Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn; Zhang, Qi; Li, Xiaona; Qiang, Jianbing; Wang, Younian

2017-07-15

The changes in structure and surface morphology of metallic glasses Fe{sub 80}Si{sub 7.43}B{sub 12.57} and Fe{sub 68}Zr{sub 7}B{sub 25} before and after the irradiation of He ions with the energy of 300 keV were investigated, and were compared with that of the tungsten. The results show that after the He{sup 2+} irradiation, metallic glass Fe{sub 68}Zr{sub 7}B{sub 25} still maintained amorphous. While a small amount of metastable β-Mn type phase nanocrystals formed in metallic glass Fe{sub 80}Si{sub 7.43}B{sub 12.57} at the fluence of 4.0 × 10{sup 17}ions/cm{sup 2} (19dpa). The nanocrystals transformed into α-Fe phase and tetragonal Fe{sub 2}B phase as the fluence increased to 1.0 × 10{sup 18}ions/cm{sup 2} (47dpa). Then the new orthogonal Fe{sub 3}B phase and β-Mn type phase nanocrystals appeared when the fluence increased further, and the quantities of nanocrystals increased. Blisters and cracks appeared on the surface of tungsten under the irradiation fluence of 1.0 × 10{sup 18}ions/cm{sup 2}, however only when the fluence was up to 1.6 × 10{sup 18}ions/cm{sup 2}, could cracks and spalling appear on the surfaces of metallic glasses. - Highlights: •Metallic glass Fe{sub 68}Zr{sub 7}B{sub 25} could maintain amorphous state after the irradiation. •A series of crystallization behaviors occurred in metallic glass Fe{sub 80}Si{sub 7.43}B{sub 12.57}. •The surface of tungsten appeared blisters at the fluence of 1.0 × 10{sup 18} ions/cm{sup 2}. •Surfaces of Fe-based metallic glasses cracked at the fluence of 1.6 × 10{sup 18}ions/cm{sup 2}.

Structure and dynamics of hydrated Fe(II) and Fe(III) ions. Quantum mechanical and molecular mechanical simulations

International Nuclear Information System (INIS)

Remsungnen, T.

2002-11-01

Classical molecular dynamics (MD) and combined em ab initio quantum mechanical/molecular mechanical molecular dynamics (QM/MM-MD) simulations have been performed to investigate structural, dynamical and energetical properties of Fe(II), and Fe(III) transition metal ions in aqueous solution. In the QM/MM-MD simulations the ion and its first hydration sphere were treated at the Hartree-Fock ab initio quantum mechanical level, while ab initio generated pair plus three-body potentials were employed for the remaining system. For the classical MD simulation the pair plus three-body potential were employed for all ion-water interactions. The coordination number of the first hydration shell is 100 % of 6 in both cases. The number of waters in the second hydration shell obtained from classical simulations are 13.4 and 15.1 for Fe(II) and Fe(III), respectively, while QM/MM-MD gives the values of 12.4 and 13.4 for Fe(II) and Fe(III). The energies of hydration obtained from MD and QM/MM-MD for Fe(II) are 520 and 500 kcal/mol, and for Fe(III) 1160 and 1100 kcal/mol respectively. The mean residence times of water in the second shell obtained from QM/MM-MD are 24 and 48 ps for Fe(II) and Fe(III), respectively. In contrast to the data obtained from classical MD simulation, the QM/MM-MD values are all in good agreement with the experimental data available. These investigations and results clearly indicate that many-body effects are essential for the proper description of all properties of the aqueous solution of both Fe(II) and Fe(III) ions. (author)

HZE dosimetry in space using plastic track detectors

CERN Document Server

Kopp, J; Reitz, G; Enge, W

1999-01-01

Plastic nuclear track detectors were used to measure the contribution of High charge Z and energy E (HZE) particles to the radiation exposure of manned space missions. Results from numerous space missions in the orbit planned for the International Space Station are compared. The measurements cover the declining phase of the last solar cycle during the past 7 years and various shielding conditions inside the US Space Shuttle and the Russian MIR-station.

Independency of Fe ions in hemoglobin on immunomagnetic reduction assay

International Nuclear Information System (INIS)

Yang, S.Y.; Lan, C.B.; Chen, C.H.; Horng, H.E.; Hong, Chin-Yih; Yang, H.C.; Lai, Y.K.; Lin, Y.H.; Teng, K.S.

2009-01-01

Immunomagnetic reduction (IMR), which involves measuring the reduction in the ac magnetic susceptibility of magnetic reagents, is due to the association between bio-functionalized magnetic nanoparticles and target bio-molecules. This has been demonstrated for assaying proteins in solutions free of Fe ions, such as serum. In this work, the validity of IMR assay for samples rich in Fe ions like hemoglobin (Hb) is investigated. According to the results, there is no magnetic signal contributed by Fe-ion-rich Hb. Furthermore, the results show a high sensitivity in assaying hemoglobin A1c (HbA1c) by using IMR.

Independency of Fe ions in hemoglobin on immunomagnetic reduction assay

Energy Technology Data Exchange (ETDEWEB)

Yang, S.Y. [MagQu Co. Ltd., Sindian City, Taipei County 231, Taiwan (China); Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China); Lan, C.B.; Chen, C.H. [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China); Horng, H.E. [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China)], E-mail: phyfv001@scc.ntnu.edu.tw; Hong, Chin-Yih [Department of Mechanical Engineering, Nan-Kai University of Technology, Nantau County, Taiwan (China)], E-mail: cyhong@nkut.edu.tw; Yang, H.C. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)], E-mail: hcyang@phys.ntu.edu.tw; Lai, Y.K. [College of Life Sciences, National Tsing Hua University, Hsinchu City 300, Taiwan (China); Department of Bioresources, Da-Yeh University, Changhua 515, Taiwan (China); Lin, Y.H.; Teng, K.S. [Apex Biotechnology Co. Ltd., Hsinchu City 300, Taiwan (China)

2009-10-15

Immunomagnetic reduction (IMR), which involves measuring the reduction in the ac magnetic susceptibility of magnetic reagents, is due to the association between bio-functionalized magnetic nanoparticles and target bio-molecules. This has been demonstrated for assaying proteins in solutions free of Fe ions, such as serum. In this work, the validity of IMR assay for samples rich in Fe ions like hemoglobin (Hb) is investigated. According to the results, there is no magnetic signal contributed by Fe-ion-rich Hb. Furthermore, the results show a high sensitivity in assaying hemoglobin A1c (HbA1c) by using IMR.

Post-annealing recrystallization and damage recovery process in Fe ion implanted Si

International Nuclear Information System (INIS)

Naito, Muneyuki; Hirata, Akihiko; Ishimaru, Manabu; Hirotsu, Yoshihiko

2007-01-01

We have investigated ion-beam-induced and thermal annealing-induced microstructures in high fluence Fe implanted Si using transmission electron microscopy. Si(1 1 1) substrates were irradiated with 120 keV Fe ions at 120 K to fluences of 0.4 x 10 17 and 4.0 x 10 17 cm -2 . A continuous amorphous layer was formed on Si substrates in both as-implanted samples. After thermal annealing at 1073 K for 2 h, β-FeSi 2 fine particles buried in a polycrystalline Si layer were observed in the low fluence sample, while a continuous β-FeSi 2 layer was formed in the high fluence sample. We discuss the relationship between ion fluence and defects recovery process in Fe ion implanted Si

Spectroscopic properties of Fe2+ ions at tetragonal sites-Crystal field effects and microscopic modeling of spin Hamiltonian parameters for Fe2+ (S=2) ions in K2FeF4 and K2ZnF4

International Nuclear Information System (INIS)

Rudowicz, C.; Piwowarska, D.

2011-01-01

Magnetic and spectroscopic properties of the planar antiferromagnet K 2 FeF 4 are determined by the Fe 2+ ions at tetragonal sites. The two-dimensional easy-plane anisotropy exhibited by K 2 FeF 4 is due to the zero field splitting (ZFS) terms arising from the orbital singlet ground state of Fe 2+ ions with the spin S=2. To provide insight into the single-ion magnetic anisotropy of K 2 FeF 4 , the crystal field theory and the microscopic spin Hamiltonian (MSH) approach based on the tensor method is adopted. Survey of available experimental data on the crystal field energy levels and free-ion parameters for Fe 2+ ions in K 2 FeF 4 and related compounds is carried out to provide input for microscopic modeling of the ZFS parameters and the Zeeman electronic ones. The ZFS parameters are expressed in the extended Stevens notation and include contributions up to the fourth-order using as perturbation the spin-orbit and electronic spin-spin couplings within the tetragonal crystal field states of the ground 5 D multiplet. Modeling of the ZFS parameters and the Zeeman electronic ones is carried out. Variation of these parameters is studied taking into account reasonable ranges of the microscopic ones, i.e. the spin-orbit and spin-spin coupling constants, and the energy level splittings, suitable for Fe 2+ ions in K 2 FeF 4 and Fe 2+ :K 2 ZnF 4 . Conversions between the ZFS parameters in the extended Stevens notation and the conventional ones are considered to enable comparison with the data of others. Comparative analysis of the MSH formulas derived earlier and our more complete ones indicates the importance of terms omitted earlier as well as the fourth-order ZFS parameters and the spin-spin coupling related contributions. The results may be useful also for Fe 2+ ions at axial symmetry sites in related systems, i.e. Fe:K 2 MnF 4 , Rb 2 Co 1-x Fe x F 4 , Fe 2+ :Rb 2 CrCl 4 , and Fe 2+ :Rb 2 ZnCl 4 . - Highlights: → Truncated zero field splitting (ZFS) terms for Fe 2+ in K

Ion-beam mixing and tribology of Fe/B multilayers

International Nuclear Information System (INIS)

Hu, R.; Rehn, L.E.; Baldo, P.M.; Fenske, G.R.

1990-01-01

This paper reports the interdiffusion of Fe and B trilayer specimens during 1-MeV Kr + bombardment studied using Rutherford backscattering and electron microscopy. The square of the interdiffusion distance during mixing at 300 degrees C was found to depend linearly on the irradiation dose. Arrhenius behavior with an apparent activation enthalpy of 0.7 eV was observed for the mixing between 200 and 500 degrees C. Electron microscopy of ion-beam mixed multilayer specimens revealed that two crystalline compounds, Fe 2 B and Fe 3 B, formed during bombardment at 450 degrees C, while two different amorphous Fe/B phases formed at 300 degrees C. Substantially improved adhesion and reduced friction were observed for Fe/B multilayers ion-beam mixed onto M50 steel substrates at 450 degrees C

Dielectronic recombination of Be-like Fe ion

International Nuclear Information System (INIS)

Moribayashi, Kengo; Kato, Takako.

1996-04-01

Energy level(E), radiative transition probability(Ar), and autoionization rate(Aa) for Be-like Fe 22+ ion are calculated with use of Cowan's code. Using these atomic data, the dielectronic recombination rate coefficient(α) to the excited states and the intensity factor(Qd) of the dielectronic satellite lines have been calculated. The doubly excited states 1s 2 3lnl' as well as the 1s 2 2pnl of Fe 22+ ion are considered. The results are given in tables and figures. The n- and l-dependence for Ar, Aa, and α is studied. With use of it, Aa and Ar at large n are extrapolated. The dielectronic recombination processes from the 1s 2 2pnl and those from the 1s 2 3lnl' dominate at low and at high temperature, respectively. The qualitative different behaviors for E, Ar, and α between Be-like ions and He-like ions are discussed with use of atomic nuclear charge scaling. (author)

Surface sputtering in high-dose Fe ion implanted Si

International Nuclear Information System (INIS)

Ishimaru, Manabu

2007-01-01

Microstructures and elemental distributions in high-dose Fe ion implanted Si were characterized by means of transmission electron microscopy and Rutherford backscattering spectroscopy. Single crystalline Si(0 0 1) substrates were implanted at 350 deg. C with 120 keV Fe ions to fluences ranging from 0.1 x 10 17 to 4.0 x 10 17 /cm 2 . Extensive damage induced by ion implantation was observed inside the substrate below 1.0 x 10 17 /cm 2 , while a continuous iron silicide layer was formed at 4.0 x 10 17 /cm 2 . It was found that the spatial distribution of Fe projectiles drastically changes at the fluence between 1.0 x 10 17 and 4.0 x 10 17 /cm 2 due to surface sputtering during implantation

Transient field for W ions traversing Fe hosts and for Os ions traversing Fe and Ni hosts

International Nuclear Information System (INIS)

Stuchbery, A.E.; Bolotin, H.H.; Doran, C.E.

1987-02-01

Transient field strengths were measured for 184 W and 186 W ions traversing thin, magnetized Fe foils with velocities in the range 1.8 ≤ v/v>=o ≤ 5.7 (v>=o Bohr velocity) and for 188 Os, 190 Os, 192 Os ions traversing polarized Ni hosts with average velocities =o> ∼ 4. The present measured transient field strengths, together with previously measured results for W, Os ions, are compared with transient-field strength parametrizations, and discussed in terms of microscopic models of the transient field

Melting of Au and Al in nanometer Fe/Au and Fe/Al multilayers under swift heavy ions: A thermal spike study

International Nuclear Information System (INIS)

Chettah, A.; Wang, Z.G.; Kac, M.; Kucal, H.; Meftah, A.; Toulemonde, M.

2006-01-01

Knowing that Fe is sensitive to swift heavy ion irradiations whereas Au and Al are not, the behavior of nanometric metallic multilayer systems, like [Fe(3 nm)/Au(x)] y and [Fe(3 nm)/Al(x)] y with x ranging between 1 and 10 nm, were studied within the inelastic thermal spike model. In addition to the usual cylindrical geometry of energy dissipation perpendicular to the ion projectile direction, the heat transport along the ion path was implemented in the electronic and atomic sub-systems. The simulations were performed using three different values of linear energy transfer corresponding to 3 MeV/u of 208 Pb, 132 Xe and 84 Kr ions. For the Fe/Au system, evidence of appearance of a molten phase was found in the entire Au layer, provided the Au thickness is less than 7 nm and 3 nm for Pb and Xe ions, respectively. For the Fe/Al(x) system irradiated with Pb ions, the Al layers with a thickness less than 4 nm melt along the entire ion track. Surprisingly, the Fe layer does not melt if the Al thickness is larger than 2 nm, although the deposited energy surpasses the electronic stopping power threshold of track formation in Fe. For Kr ions melting does not occur in any of the multilayer systems

Structural and magnetic properties of Fe-Al silica composites prepared by sequential ion implantation

International Nuclear Information System (INIS)

Julian Fernandez, C. de; Tagliente, M.A.; Mattei, G.; Sada, C.; Bello, V.; Maurizio, C.; Battaglin, G.; Sangregorio, C.; Gatteschi, D.; Tapfer, L.; Mazzoldi, P.

2004-01-01

The nanostructural and magnetic properties of Fe-Al/SiO 2 granular solids prepared by ion implantation have been investigated. A strong effect of the implantation order of the Fe and Al ions has been evidenced. By implanting first the Al ions and later Fe ions, 5-40 nm core-shell nanoparticles are formed with a magnetic behavior similar to that of Fe. The lattice parameter of the nanoparticles is consistent with that of the α-Fe. By changing the implantation order, 10-15 nm core-shell nanoparticles of a bcc Fe-based phase with a lattice 2.5% smaller than that of α-Fe are formed. The temperature dependence of the magnetization indicates a superparamagnetic behavior

Structural and magnetic properties of Fe-Al silica composites prepared by sequential ion implantation

Energy Technology Data Exchange (ETDEWEB)

Julian Fernandez, C. de E-mail: dejulian@padova.infm.it; Tagliente, M.A.; Mattei, G.; Sada, C.; Bello, V.; Maurizio, C.; Battaglin, G.; Sangregorio, C.; Gatteschi, D.; Tapfer, L.; Mazzoldi, P

2004-02-01

The nanostructural and magnetic properties of Fe-Al/SiO{sub 2} granular solids prepared by ion implantation have been investigated. A strong effect of the implantation order of the Fe and Al ions has been evidenced. By implanting first the Al ions and later Fe ions, 5-40 nm core-shell nanoparticles are formed with a magnetic behavior similar to that of Fe. The lattice parameter of the nanoparticles is consistent with that of the {alpha}-Fe. By changing the implantation order, 10-15 nm core-shell nanoparticles of a bcc Fe-based phase with a lattice 2.5% smaller than that of {alpha}-Fe are formed. The temperature dependence of the magnetization indicates a superparamagnetic behavior.

Phase formation in Zr/Fe multilayers during Kr ion irradiation

International Nuclear Information System (INIS)

Motta, A. T.

1998-01-01

A detailed study has been conducted of the effect of Kr ion irradiation on phase formation in Zr-Fe metallic multilayers, using the Intermediate Voltage Electron Microscopy (IVEM) at Argonne National Laboratory. Metallic multilayers were prepared with different overall compositions (near 50-50 and Fe-rich), and with different wavelengths (repetition thicknesses). These samples were irradiated with 300 keV Kr ions at various temperatures to investigate the final products, as well as the kinetics of phase formation. For the shorter wavelength samples, the final product was in all cases an amorphous Zr-Fe phase, in combination with Fe, while specially for the larger wavelength samples, in the Fe-rich samples the intermetallic compounds ZrFe 2 and Zr 3 Fe were formed in addition to the amorphous phase. The dose to full reaction decreases with temperature, and with wavelength in a manner consistent with a diffusion-controlled reaction

Sequestering of Fe and Pb ions from Wastewater by Canarium ...

African Journals Online (AJOL)

In this paper agricultural waste; Canarium schweinfurthii was explored for the sequestering of Fe and Pb ions from wastewater solution after carbonization and chemical treatment at 400oC. Optimum time of 30 and 150 min with percentage removal of 95 and 98% at optimum pH of 2 and 6 was obtained for Fe and Pb ions.

Role of HZE particles in space flight - Results from spaceflight and ground-based experiments

Energy Technology Data Exchange (ETDEWEB)

Buecker, H.; Facius, R.

1981-09-01

Selected results from experiments investigating the potentially specific radiobiological importance of the cosmic HZE (equals high Z, energetic) particles are discussed. Results from the Biostack space flight experiments, which were designed to meet the experimental requirements imposed by the microdosimetric nature of this radiation field, clearly indicate the existence of radiation mechanisms which become effective only at higher values of LET (linear energy transfer). Accelerator irradiation studies are reviewed which conform with this conjecture. The recently discovered production of 'micro-lesions' in mammalian tissues by single HZE particles is possibly the most direct evidence. Open questions concerning the establishment of radiation standards for manned spaceflight, such as late effects, interaction with flight dynamic parameters, and weightlessness, are indicated.

Formation of two ripple modes on Si by ion erosion with simultaneous Fe incorporation

International Nuclear Information System (INIS)

Cornejo, Marina; Ziberi, Bashkim; Meinecke, Christoph; Frost, Frank

2011-01-01

This report focuses on the self organized nanostructure formation on Si (0 0 1) by erosion with low energy Kr + ions with simultaneous incorporation of metallic atoms, in particular Fe. The incorporation of Fe is thought to play an important role in the formation of some features. In the experimental set-up used here the Fe atoms come from the sputtering of a cylindrical stainless steel target situated between the source and the sample holder. It is demonstrated how the Fe flux can be regulated by operational parameters of the ion source. It is shown that two different ripple modes, one perpendicular to the ion beam projection on the surface and the other parallel, were formed at near normal incidence (α = 20 o ) with ion energy between 300 eV and 2000 eV and a fluence of 6.7 x 10 18 cm -2 . The perpendicular mode ripples dominated the topography when E ion = 2000 eV, while the parallel mode ripples were the main features observed when E ion = 300 eV. The correlation of Fe concentration with ion sources parameters and resulting topography is analyzed. It is demonstrated that a certain Fe concentration is necessary for the formation of ripples that are oriented perpendicular to the ion beam and that the Fe concentration alone does not determine the evolving topography.

Charged particle mutagenesis at low dose and fluence in mouse splenic T cells

Energy Technology Data Exchange (ETDEWEB)

Grygoryev, Dmytro [Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239 (United States); Gauny, Stacey [Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Lasarev, Michael; Ohlrich, Anna [Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239 (United States); Kronenberg, Amy [Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Turker, Mitchell S., E-mail: turkerm@ohsu.edu [Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239 (United States); Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239 (United States)

2016-06-15

Highlights: • Densely ionizing forms of space radiation induce mutations in splenic T cells at low fluence. • Large interstitial deletions and discontinuous LOH patterns are radiation signature mutations. • Space radiation mutagenesis suggests a cancer risk from deep space travel. - Abstract: High-energy heavy charged particles (HZE ions) found in the deep space environment can significantly affect human health by inducing mutations and related cancers. To better understand the relation between HZE ion exposure and somatic mutation, we examined cell survival fraction, Aprt mutant frequencies, and the types of mutations detected for mouse splenic T cells exposed in vivo to graded doses of densely ionizing {sup 48}Ti ions (1 GeV/amu, LET = 107 keV/μm), {sup 56}Fe ions (1 GeV/amu, LET = 151 keV/μm) ions, or sparsely ionizing protons (1 GeV, LET = 0.24 keV/μm). The lowest doses for {sup 48}Ti and {sup 56}Fe ions were equivalent to a fluence of approximately 1 or 2 particle traversals per nucleus. In most cases, Aprt mutant frequencies in the irradiated mice were not significantly increased relative to the controls for any of the particles or doses tested at the pre-determined harvest time (3–5 months after irradiation). Despite the lack of increased Aprt mutant frequencies in the irradiated splenocytes, a molecular analysis centered on chromosome 8 revealed the induction of radiation signature mutations (large interstitial deletions and complex mutational patterns), with the highest levels of induction at 2 particles nucleus for the {sup 48}Ti and {sup 56}Fe ions. In total, the results show that densely ionizing HZE ions can induce characteristic mutations in splenic T cells at low fluence, and that at least a subset of radiation-induced mutant cells are stably retained despite the apparent lack of increased mutant frequencies at the time of harvest.

In Situ Studies of Fe4+ Stability in β-Li3Fe2(PO4)3 Cathodes for Li Ion Batteries

DEFF Research Database (Denmark)

Christiansen, Ane Sælland; Johnsen, Rune E.; Norby, Poul

2015-01-01

In commercial Fe-based batteries the Fe2+/Fe3+ oxidation states are used, however by also utilizing the Fe4+ oxidation state, intercalation of up to two Li ions per Fe ion could be possible. In this study, we investigate whether Fe4+ can be formed and stabilized in β-Li3Fe2(PO4)3. The work includes...... of Fe4+ formation. Oxidation of the organic electrolyte is inevitable at 4.5 V but this alone cannot explain the volume change. Instead, a reversible oxygen redox process (O2− → O−) could possibly explain and charge compensate for the reversible extraction of lithium ions from β-Li3Fe2(PO4)3....... in situ synchrotron X-ray powder diffraction studies (XRPD) during charging of β-Li3Fe2(PO4)3 up to 5.0 V vs. Li/Li+. A novel capillary-based micro battery cell for in situ XRPD has been designed for this. During charge, a plateau at 4.5 V was found and a small contraction in volume was observed...

Simulation of TGF-Beta Activation by Low-Dose HZE Radiation in a Cell Culture

Science.gov (United States)

Plante, Ianik; Cucinotta, Francis A.

2009-01-01

High charge (Z) and energy (E) (HZE) nuclei comprised in the galactic cosmic rays are main contributors to space radiation risk. They induce many lesions in living matter such as non-specific oxidative damage and the double-strand breaks (DSBs), which are considered key precursors of early and late effects of radiation. There is increasing evidence that cells respond collectively rather than individually to radiation, suggesting the importance of cell signaling1. The transforming growth factor (TGF ) is a signaling peptide that is expressed in nearly all cell type and regulates a large array of cellular processes2. TGF have been shown to mediate cellular response to DNA damage3 and to induce apoptosis in non-irradiated cells cocultured with irradiated cells4. TFG molecules are secreted by cells in an inactive complex known as the latency-associated peptide (LAP). TGF is released from the LAP by a conformational change triggered by proteases, thrombospondin-1, integrins, acidic conditions and .OH radical5. TGF then binds to cells receptors and activates a cascade of events mediated by Smad proteins6, which might interfere with the repair of DNA. Meanwhile, increasingly sophisticated Brownian Dynamics (BD) algorithms have appeared recently in the literature7 and can be applied to study the interaction of molecules with receptors. These BD computer models have contributed to the elucidation of signal transduction, ligand accumulation and autocrine loops in the epidermal growth factor (EGF) and its receptor (EFGR) system8. To investigate the possible roles of TGF in an irradiated cell culture, our Monte-Carlo simulation codes of the radiation track structure9 will be used to calculate the activation of TFG triggered by .OH produced by low doses of HZE ions. The TGF molecules will then be followed by a BD algorithm in a medium representative of a cell culture to estimate the number of activated receptors.

Improvement of the magnetic moment of NiZn ferrites induced by substitution of Nd3+ ions for Fe3+ ions

Science.gov (United States)

Wu, Xuehang; Chen, Wen; Wu, Wenwei; Wu, Juan; Wang, Qing

2018-05-01

Four types of Ni-Zn based ferrites materials having the general formula Ni0.5Zn0.5NdxFe2-xO4 (0.0 ≤ x ≤ 0.12) have been successfully synthesized by calcining oxalates in air and the influence of Nd content on the structure and magnetic properties of Ni0.5Zn0.5NdxFe2-xO4 is studied. X-ray diffraction examination confirms that a high-crystallized Ni0.5Zn0.5NdxFe2-xO4 with cubic spinel structure is obtained when the precursor is calcined at 1000 °C in air for 2 h. The substitutions of Nd3+ ions for partial Fe3+ ions do not change the spinel crystalline structure of MFe2O4. The incorporation of Nd3+ ions in place of Fe3+ ions in Ni-Zn ferrites increases the average crystallite size. Specific saturation magnetization decreases with increase in Nd content. This is because Nd3+ ions with smaller magnetic moment preferentially fill the octahedral sites. In addition, antiferromagnetic FeNdO3 increases with increase in Nd content. In this study, Ni0.5Zn0.5Nd0.08Fe1.92O4, calcined at 1000 °C, exhibits the highest magnetic moment (4.2954 μB) and the lowest coercivity (28.82 Oe).

Irradiation effects in Fe-30%Ni alloy during Ar ion implantation

International Nuclear Information System (INIS)

Soukieh, Mohamad; Al-Mohamad, Ali

1993-12-01

The use of metallic thin films for studying the processes which take place during ion irradiation has recently increased. For example, ion implantation is widely used to study the structural defects in transition metallic thin films such as (Fe, Ni, Co), because it can simulate the effects occurring in nuclear reactors during neutron irradiation especially the swelling of reactor materials. The swelling of metals and alloys is strongly related to the material structure and to the irradiation conditions. The general feature of formation of structural defects as a function of irradiation dosage and annealing temperature is well known. However, the detailed mechanisms are still not well understood. For example, the swelling of iron alloy with 30-35% nickel is very small in comparison with other Ni concentrations, and there is no clear information on the possibility of phase transitions in fe-Ni alloys during irradiation. The aim of this work is to study the phase-structural changes in Fe-30% Ni implanted by high dose of argon ions. The effect of irradiation with low energy argon ions (40 KeV, and fluences of 10.E15 to 10.E17 ions/cm) on the deposited thin films of Fe-30% Ni alloy was investigated using RBS and TEM techniques. The thicknesses of these films were about 65+-10 nm deposited on ceramic, KBr, and Be fiols substrates. Gas bubble formation and profile distribution of the implanted argon ions were investigated. Formation of an ordered phase Fe 3 Ni during irradiation appears to inhibit gas bubble formations in the film structure. (author). 17 refs., 15 figs., 7 tabs

Moessbauer study of FePO4 cathode for lithium- and sodium-ion batteries

International Nuclear Information System (INIS)

Tetsuaki Nishida; Masahiro Tokunaga; Toshiharu Nishizumi; Takafumi Yamamoto; Tomoyuki Shiratsuchi; Shigeto Okada; Jun-ichi Yamaki

2005-01-01

LiFePO 4 of olivine type has attracted much interest as a rare-metal free cathode for lithium-ion battery. The present authors' group has found a low-cost preparation method for new cathode material FePO 4 (P 321 ) from an aqueous solution of metallic iron and P 2 O 5 . A cathode pellet was prepared by mixing FePO 4 , acetylene black (AB) and polytetrafluoroethylene (PTFE) binder at a mass ratio of 70:25:5. Electrochemical cathode performance was investigated under a constant current density of 0.1 mA/cm 2 with a coin-type cell with an anode of metallic Li and Na for Li- and Na-ion batteries, respectively. Moessbauer spectra were measured by a constant accele- ration method with a Moessbauer source of 57 Co(Pd) and an α-Fe foil as a reference of the isomer shift. Moessbauer spectra of the original cathode pellet top left and right) composed of amorphous FePO 4 indicate that all the Fe III atoms have a tetrahedral symmetry. After discharging the Li-(second left) and Na-batteries (second right), all the Fe III were reduced to octahedral Fe II . The reduction of Fe III to Fe II indicates penetration of Li + and Na + into the FePO 4 cathode which accompanies an electron capture; Li + (or Na + ) + Fe III PO 4 + e - = LiFe II PO 4 (or NaFe II PO 4 ) After charging the Li-cell (bottom left), all the Fen atoms were oxidized to tetrahedral Fe III , while 69 % of Fe II was oxidized to Fe III in the Na-ion cell (bottom right) due to a lower cell voltage: 4.0 V. Oxidation of Fe II to Fe III reflects a release of Li + or Na + ions from the FePO 4 cathode to the electrolyte, i.e., an inverse reaction of eq.

Iron loading effects in Fe/SSZ-13 NH3-SCR catalysts: nature of the Fe-ions and structure-function relationships

Energy Technology Data Exchange (ETDEWEB)

Gao, Feng; Zheng, Yang; Kukkadapu, Ravi K.; Wang, Yilin; Walter, Eric D.; Schwenzer, Birgit; Szanyi, Janos; Peden, Charles HF

2016-05-06

Using a traditional aqueous solution ion-exchange method under a protecting atmosphere of N2, a series of Fe/SSZ-13 catalysts with various Fe loadings were synthesized. UV-Vis, EPR and Mössbauer spectroscopies, coupled with temperature programmed reduction and desorption techniques, were used to probe the nature of the Fe sites. The major monomeric and dimeric Fe species are extra-framework [Fe(OH)2]+ and [HO-Fe-O-Fe-OH]2+. Larger oligomers with unknown nuclearity, poorly crystallized Fe2O3 particles, together with isolated Fe2+ ions, are minor Fe-containing moieties. Reaction rate and Fe loading correlations suggest that isolated Fe3+ ions are the active sites for standard SCR while the dimeric sites are the active centers for NO oxidation. NH3 oxidation, on the other hand, is catalyzed by sites with higher nuclearity. A low-temperature standard SCR reaction network is proposed that includes redox cycling of both monomeric and dimeric Fe species, for SCR and NO2 generation, respectively. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Program for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.

Oxide ion diffusion mechanism related to Co and Fe ions in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ using in-situ X-ray absorption spectroscopy

Science.gov (United States)

Itoh, Takanori; Imai, Hideto

2018-03-01

The time changes of the white line and pre-edge intensities of Co and Fe K-edge in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ (BSCF) were observed to estimate the oxide ion diffusion related to Co and Fe ions by using in - situ X-ray absorption spectroscopy (XAS) during oxidation. The 20 μm self-standing BSCF film was prepared for in - situ XAS measurements. The time changes of absorption were fitted to the exponential decay function with two terms. The longer relaxation time (τ), related to the oxide ion diffusion during the oxidation of BSCF, is dependent on temperature. The oxide ion diffusion coefficients (D) were calculated from the τ s estimated by in - situ XAS. The values of the activation energy (Ea) for D related to Co K-edge white line, Co pre-edge, and Fe pre-edge were 1.8-2.0 eV. The value of Ea for D related to Fe K-edge white line, however, was higher than other absorption values at approximately 2.3 eV. We discussed the oxide ion diffusion mechanism related to Co and Fe ions in BSCF using in - situ XAS.

Anti-biofilm activity of Fe heavy ion irradiated polycarbonate

Energy Technology Data Exchange (ETDEWEB)

Joshi, R.P. [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Hareesh, K., E-mail: appi.2907@gmail.com [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Bankar, A. [Department of Microbiology, Waghire College, Pune 412301 (India); Sanjeev, Ganesh [Microtron Centre, Department of Studies in Physics, Mangalore University, Mangalore 574166 (India); Asokan, K.; Kanjilal, D. [Inter University Accelerator Centre, Arun Asaf Ali Marg, New Delhi 110067 (India); Dahiwale, S.S.; Bhoraskar, V.N. [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

2016-10-01

Highlights: • PC films were irradiated by 60 and 120 MeV Fe ions. • Irradiated PC films showed changes in its physical and chemical properties. • Irradiated PC also showed more anti-biofilm activity compared to pristine PC. - Abstract: Polycarbonate (PC) polymers were investigated before and after high energy heavy ion irradiation for anti-bacterial properties. These PC films were irradiated by Fe heavy ions with two energies, viz, 60 and 120 MeV, at different fluences in the range from 1 × 10{sup 11} ions/cm{sup 2} to 1 × 10{sup 13} ions/cm{sup 2}. UV-Visible spectroscopic results showed optical band gap decreased with increase in ion fluences due to chain scission mainly at carbonyl group of PC which is also corroborated by Fourier transform infrared spectroscopic results. X-ray diffractogram results showed decrease in crystallinity of PC after irradiation which leads to decrease in molecular weight. This is confirmed by rheological studies and also by differential scanning calorimetric results. The irradiated PC samples showed modification in their surfaces prevents biofilm formation of human pathogen, Salmonella typhi.

Uptake of CrO42- ions by Fe-treated tri-calcium phosphate

International Nuclear Information System (INIS)

Serrano G, J.; Ramirez S, J. L.; Bonifacio M, J.; Granados C, F.; Badillo A, V. E.

2010-01-01

CrO 4 2- ion adsorption of Fe-treated tri-calcium phosphate was studied by batch experiments as a function of contact time, initial concentration of metal ion and temperature. Adsorption results showed that at ph 5.5 and 1.0 x 10 -4 M chromium concentration the adsorption capacity of Fe-treated tri-calcium phosphate for CrO 4 2- ions was 7.10 x 10 -3 mmol/g. Chromium adsorption data on Fe-treated tri-calcium phosphate at various initial concentration fitted the Freundlich isotherm. By temperature studies the thermodynamic parameters ΔH 0 , ΔG 0 and ΔS 0 were estimated and the obtained results showed that the adsorption reaction was endothermic and spontaneous. (Author)

Adsorption kinetic parameters of Fe3+ and Ni2+ ions by gyrolite

Directory of Open Access Journals (Sweden)

Kestutis Baltakys

2015-03-01

Full Text Available In this work the adsorption kinetic parameters for Fe3+ and Ni2+ ions by gyrolite are presented. Additionally, the adsoption mechanism was described by using pseudo first order and pseudo second order  equations. It was determined that the adsorption capacity of gyrolite and intrusion of heavy metals ions in its structure depends on reaction time and the pH value of adsorptive. It was observed that the incorporation of Fe3+ ions occurs more intensive than Ni2+ ions. It was found that in the acidic solution the intrusion of Fe3+ ions into gyrolite structure proceeds by two types of chemical reaction mechanisms: substitution and addition. Meanwhile, nickel ions were participated only in substitution reaction: gyrolite-Ca0 + Mex+ ↔ gyrolite-Me0 + Ca2+. It was observed that the pseudo second order model fit well for iron and nickel ions adsorption mechanism. It was estimated that the adsorption reactions are not reversible process and the crystal structure of gyrolite is stable. Moreover, synthetic adsorbent and the products of sorption were characterized by XRD, STA and FT-IR methods.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5735

Relative Biological Effectiveness of HZE Particles for Chromosomal Exchanges and Other Surrogate Cancer Risk Endpoints.

Directory of Open Access Journals (Sweden)

Eliedonna Cacao

Full Text Available The biological effects of high charge and energy (HZE particle exposures are of interest in space radiation protection of astronauts and cosmonauts, and estimating secondary cancer risks for patients undergoing Hadron therapy for primary cancers. The large number of particles types and energies that makeup primary or secondary radiation in HZE particle exposures precludes tumor induction studies in animal models for all but a few particle types and energies, thus leading to the use of surrogate endpoints to investigate the details of the radiation quality dependence of relative biological effectiveness (RBE factors. In this report we make detailed RBE predictions of the charge number and energy dependence of RBE's using a parametric track structure model to represent experimental results for the low dose response for chromosomal exchanges in normal human lymphocyte and fibroblast cells with comparison to published data for neoplastic transformation and gene mutation. RBE's are evaluated against acute doses of γ-rays for doses near 1 Gy. Models that assume linear or non-targeted effects at low dose are considered. Modest values of RBE (10 are predicted at low doses <0.1 Gy. The radiation quality dependence of RBE's against the effects of acute doses γ-rays found for neoplastic transformation and gene mutation studies are similar to those found for simple exchanges if a linear response is assumed at low HZE particle doses. Comparisons of the resulting model parameters to those used in the NASA radiation quality factor function are discussed.

Porous Fe2O3 Microspheres as Anode for Lithium-Ion Batteries

Science.gov (United States)

Noerochim, L.; Indra, M. A. T.; Purwaningsih, H.; Subhan, A.

2018-05-01

In this work, Fe2O3 was successfully synthesized by the hydrothermal process at low temperature. FeCl3.6H2O as precursor and variation of lysine as hydrolyzing agent were used to preparing Fe2O3. SEM images show that the morphology of Fe2O3 is porous microsphere with sizes in the range of (1 to 5) µm in diameter. The as-prepared Fe2O3 with the 2 M of lysine exhibits excellent cycling performance when used as the anode for lithium ion batteries, obtaining reversible discharge capacity of 172.33 mA·h·g‑1 at 0.5 C after 50 cycles. It is attributed to the unique structure of porous microspheres providing a large surface area which maintains good electronic contact between particles during charge-discharge process. This result demonstrates that Fe2O3 porous microsphere has a high potential as anode material for application of lithium-ion battery.

Surface damage in TEM thick α-Fe samples by implantation with 150 keV Fe ions

International Nuclear Information System (INIS)

Aliaga, M.J.; Caturla, M.J.; Schäublin, R.

2015-01-01

We have performed molecular dynamics simulations of implantation of 150 keV Fe ions in pure bcc Fe. The thickness of the simulation box is of the same order of those used in in situ TEM analysis of irradiated materials. We assess the effect of the implantation angle and the presence of front and back surfaces. The number and type of defects, ion range, cluster distribution and primary damage morphology are studied. Results indicate that, for the very thin samples used in in situ TEM irradiation experiments the presence of surfaces affect dramatically the damage produced. At this particular energy, the ion has sufficient energy to damage both the top and the back surfaces and still leave the sample through the bottom. This provides new insights on the study of radiation damage using TEM in situ

Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

Energy Technology Data Exchange (ETDEWEB)

Wang, Henan; Zheng, Yang; Li, Yan, E-mail: liyan@buaa.edu.cn; Jiang, Chengbao

2017-05-01

Highlights: • Fe{sub 2}O{sub 3}/ZnO oxides were formed on the surface of Zn implanted pure Fe samples. • The corrosion rate of the pure Fe in SBF was increased after Zn implantation. • Cytocompatibility of the pure Fe was improved by Zn ion implantation. - Abstract: Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40–60 nm and Fe{sub 2}O{sub 3}/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (E{sub corr}) and a 10-fold increase in the corrosion current density (i{sub corr}) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Acridine-based fluorescence chemosensors for selective sensing of Fe3+ and Ni2+ ions

Science.gov (United States)

Wang, Chaoyu; Fu, Jiaxin; Yao, Kun; Xue, Kun; Xu, Kuoxi; Pang, Xiaobin

2018-06-01

Two novel acridine-based fluorescence chemosensors (L1 and L2) were prepared and their metal ions sensing properties were investigated. L1 (L2) exhibited an excellent selective fluorescence response toward Fe3+ (Ni2+) and the stoichiometry ratio of L1-Fe3+ and L2-Ni2+ were 1:1. The detection limits of L1 and L2 were calculated by the fluorescence titration to be 4.13 μM and 1.52 μM, respectively, which were below the maximum permissive level of Fe3+ and Ni2+ ions in drinking water set by the EPA. The possible mechanism of the fluorescence detection of Fe3+ and Ni2+ had been proposed according to the analysis of Job's plot, IR spectra and ESI-MS. The determination of Fe3+ and Ni2+ ions in living cells had been applied successfully.

Electrochemistry of carbonaceous materials; 1. Oxidation of Sardinian coal by Fe(III) ions

Energy Technology Data Exchange (ETDEWEB)

Tomat, R.; Salmaso, R.; Zecchin, S. (CNR-Instituto di Polarografia ed Elettrochimica Preparativa, Padova (Italy))

1992-04-01

Oxidation of subbitiminous coal (Sulcis basin, Sardinia, Italy) by Fe(III) ions in aqueous H{sub 2}SO{sub 4} solution was investigated over a wide temperature range (20-80{degree}C). Experimental results are in accord with a reaction scheme involving a reversible complex between coal particles and Fe(III) ions as a first step in the oxidation process. At low coal concentration, the reaction rate follows first-order kinetics in both coal and ferric ions (overall second order), while at sufficiently high coal concentration, the reaction rate is consistent with first-order kinetics in Fe(III) concentration, appearing to be independent of coal concentration. The kinetic results obtained give preliminary information on the advantageous use of the Fe(III)/slurried coal reaction system to depolarize the anodic compartment of an electrolysis cell, for the production of H{sub 2}. 11 refs., 5 figs.

The Impact of Template Types on Polyeugenol to the Adsorption Selectivity of Ionic Imprinted Polymer (IIP) Fe Metal Ion

Science.gov (United States)

Djunaidi, M. C.; Haris, A.; Pardoyo; Rosdiana, K.

2018-04-01

The synthesis of IIP was carried out by variation of Fe(III) ion templates from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 compounds which then tested IIP selectivity to the Fe metal ions through adsorption process. Ionic Imprinted Polymer (IIP) is a method of printing metal ions bound in a polymer, subsequently released from the polymer matrix to produce a suitable imprint for the target ion. The purposes of this study were to produce IIP from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates, to know the effect of templates on adsorption selectivity of IIP involving imprint cavity, and to know the impact of metal competitor on the selectivity adsorption of IIP to the Fe metals. The results obtained showed that IIP synthesized by variations of Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates were successfully synthesized. The adsorption selectivity of Fe (III) metal ion in the Fe(NO3)3 template was greater than that of in the K3[Fe(CN)6] and NH4Fe(SO4)2 templates. The adsorption selectivity of Fe was greater on Fe-Cr compared to on Fe-Cd and Fe-Pb.

Neurochemical differences in learning and memory paradigms among rats supplemented with anthocyanin-rich blueberry diets and exposed to acute doses of 56Fe particles

Science.gov (United States)

Poulose, Shibu M.; Rabin, Bernard M.; Bielinski, Donna F.; Kelly, Megan E.; Miller, Marshall G.; Thanthaeng, Nopporn; Shukitt-Hale, Barbara

2017-02-01

The protective effects of anthocyanin-rich blueberries (BB) on brain health are well documented and are particularly important under conditions of high oxidative stress, which can lead to "accelerated aging." One such scenario is exposure to space radiation, consisting of high-energy and -charge particles (HZE), which are known to cause cognitive dysfunction and deleterious neurochemical alterations. We recently tested the behavioral and neurochemical effects of acute exposure to HZE particles such as 56Fe, within 24-48 h after exposure, and found that radiation primarily affects memory and not learning. Importantly, we observed that specific brain regions failed to upregulate antioxidant and anti-inflammatory mechanisms in response to this insult. To further examine these endogenous response mechanisms, we have supplemented young rats with diets rich in BB, which are known to contain high amounts of antioxidant-phytochemicals, prior to irradiation. Exposure to 56Fe caused significant neurochemical changes in hippocampus and frontal cortex, the two critical regions of the brain involved in cognitive function. BB supplementation significantly attenuated protein carbonylation, which was significantly increased by exposure to 56Fe in the hippocampus and frontal cortex. Moreover, BB supplementation significantly reduced radiation-induced elevations in NADPH-oxidoreductase-2 (NOX2) and cyclooxygenase-2 (COX-2), and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) in the hippocampus and frontal cortex. Overall results indicate that 56Fe particles may induce their toxic effects on hippocampus and frontal cortex by reactive oxygen species (ROS) overload, which can cause alterations in the neuronal environment, eventually leading to hippocampal neuronal death and subsequent impairment of cognitive function. Blueberry supplementation provides an effective preventative measure to reduce the ROS load on the CNS in an event of acute HZE exposure.

A Core-Shell Fe/Fe2 O3 Nanowire as a High-Performance Anode Material for Lithium-Ion Batteries.

Science.gov (United States)

Na, Zhaolin; Huang, Gang; Liang, Fei; Yin, Dongming; Wang, Limin

2016-08-16

The preparation of novel one-dimensional core-shell Fe/Fe2 O3 nanowires as anodes for high-performance lithium-ion batteries (LIBs) is reported. The nanowires are prepared in a facile synthetic process in aqueous solution under ambient conditions with subsequent annealing treatment that could tune the capacity for lithium storage. When this hybrid is used as an anode material for LIBs, the outer Fe2 O3 shell can act as an electrochemically active material to store and release lithium ions, whereas the highly conductive and inactive Fe core functions as nothing more than an efficient electrical conducting pathway and a remarkable buffer to tolerate volume changes of the electrode materials during the insertion and extraction of lithium ions. The core-shell Fe/Fe2 O3 nanowire maintains an excellent reversible capacity of over 767 mA h g(-1) at 500 mA g(-1) after 200 cycles with a high average Coulombic efficiency of 98.6 %. Even at 2000 mA g(-1) , a stable capacity as high as 538 mA h g(-1) could be obtained. The unique composition and nanostructure of this electrode material contribute to this enhanced electrochemical performance. Due to the ease of large-scale fabrication and superior electrochemical performance, these hybrid nanowires are promising anode materials for the next generation of high-performance LIBs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcriptome Profiles in Normal Human Bronchial Epithelial Cells after Exposure to gamma-rays and different HZE particles

Data.gov (United States)

National Aeronautics and Space Administration — Distinct transcriptome profiles in response to low-LET and high-LET and different radiation qualities of HZE particles. Total RNA obtained from HBEC3KT cells after 1...

Apolipoprotein E expression and behavioral toxicity of high charge, high energy (HZE) particle radiation

Science.gov (United States)

Higuchi, Yoshinori; Nelson, Gregory A.; Vazquez, Marcelo; Laskowitz, Daniel T.; Slater, James M.; Pearlstein, Robert D.

2002-01-01

Apolipoprotein E (apoE) is a lipid binding protein that plays an important role in tissue repair following brain injury. In the present studies, we have investigated whether apoE affects the behavioral toxicity of high charge, high energy (HZE) particle radiation. METHODS: Sixteen male apoE knockout (KO) mice and sixteen genetically matched wild-type (WT) C57BL mice were used in this experiment. Half of the KO and half of the WT animals were irradiated with 600 MeV/amu iron particles (2 Gy whole body). The effect of irradiation on motor coordination and stamina (Rotarod test), exploratory behavior (open field test), and spatial working and reference memory (Morris water maze) was assessed. ROTAROD TEST: Performance was adversely affected by radiation exposure in both KO and WT groups at 30 d after irradiation. By 60 d after radiation, the radiation effect was lost in WT, but still apparent in irradiated KO mice. OPEN FIELD TEST: Radiation reduced open field exploratory activity 14, 28, 56, 84, and 168 d after irradiation of KO mice, but had no effect on WT mice. MORRIS WATER MAZE: Radiation adversely affected spatial working memory in the KO mice, but had no discernible effect in the WT mice as assessed 180 d after irradiation. In contrast, irradiated WT mice showed marked impairment of spatial reference memory in comparison to non-irradiated mice, while no effect of radiation was observed in KO mice. CONCLUSIONS: These studies show that apoE expression influences the behavioral toxicity of HZE particle radiation and suggest that apoE plays a role in the repair/recovery from radiation injury of the CNS. ApoE deficiency may exacerbate the previously reported effects of HZE particle radiation in accelerating the brain aging process.

Apolipoprotein E expression and behavioral toxicity of high charge, high energy (HZE) particle radiation

International Nuclear Information System (INIS)

Higuchi, Yoshinori; Nelson, G.A.; Slater, J.M.; Pearlstein, R.D.; Laskowitz, D.T.

2002-01-01

Apolipoprotein E (apoE) is a lipid binding protein that plays an important role in tissue repair following brain injury. In the present studies, we have investigated whether apoE affects the behavioral toxicity of high charge, high energy (HZE) particle radiation. Sixteen male apoE knockout (KO) mice and sixteen genetically matched wild-type (WT) C57BL mice were used in this experiment. Half of the KO and half of the WT animals were irradiated with 600 MeV/amu iron particles (2 Gy whole body). The effect of irradiation on motor coordination and stamina (Rotarod test), exploratory behavior (open field test), and spatial working and reference memory (Morris water maze) was assessed. Rotarod test: Performance was adversely affected by radiation exposure in both KO and WT groups at 30 d after irradiation. By 60 d after radiation, the radiation effect was lost in WT, but still apparent in irradiated KO mice. Open field test: Radiation reduced open field exploratory activity 14, 28, 56, 84, and 168 d after irradiation of KO mice, but had no effect on WT mice. Morris water maze: Radiation adversely affected spatial working memory in the KO mice, but had no discernible effect in the WT mice as assessed 180 d after irradiation. In contrast, irradiated WT mice showed marked impairment of spatial reference memory in comparison to non-irradiated mice, while no effect of radiation was observed in KO mice. These studies show that apoE expression influences the behavioral toxicity of HZE particle radiation and suggest that apoE plays a role in the repair/recovery from radiation injury of the central nervous system (CNS). ApoE deficiency may exacerbate the previously reported effects of HZE particle radiation in accelerating the brain aging process. (author)

Apolipoprotein E expression and behavioral toxicity of high charge, high energy (HZE) particle radiation

Energy Technology Data Exchange (ETDEWEB)

Higuchi, Yoshinori; Nelson, G.A.; Slater, J.M.; Pearlstein, R.D. [Loma Linda Univ., CA (United States). Medical Center; Vazquez, M. [Brookhaven National Lab., Upton, NY (United States); Laskowitz, D.T. [Duke Univ., Durham, NC (United States). Medical Center

2002-12-01

Apolipoprotein E (apoE) is a lipid binding protein that plays an important role in tissue repair following brain injury. In the present studies, we have investigated whether apoE affects the behavioral toxicity of high charge, high energy (HZE) particle radiation. Sixteen male apoE knockout (KO) mice and sixteen genetically matched wild-type (WT) C57BL mice were used in this experiment. Half of the KO and half of the WT animals were irradiated with 600 MeV/amu iron particles (2 Gy whole body). The effect of irradiation on motor coordination and stamina (Rotarod test), exploratory behavior (open field test), and spatial working and reference memory (Morris water maze) was assessed. Rotarod test: Performance was adversely affected by radiation exposure in both KO and WT groups at 30 d after irradiation. By 60 d after radiation, the radiation effect was lost in WT, but still apparent in irradiated KO mice. Open field test: Radiation reduced open field exploratory activity 14, 28, 56, 84, and 168 d after irradiation of KO mice, but had no effect on WT mice. Morris water maze: Radiation adversely affected spatial working memory in the KO mice, but had no discernible effect in the WT mice as assessed 180 d after irradiation. In contrast, irradiated WT mice showed marked impairment of spatial reference memory in comparison to non-irradiated mice, while no effect of radiation was observed in KO mice. These studies show that apoE expression influences the behavioral toxicity of HZE particle radiation and suggest that apoE plays a role in the repair/recovery from radiation injury of the central nervous system (CNS). ApoE deficiency may exacerbate the previously reported effects of HZE particle radiation in accelerating the brain aging process. (author)

Structure of Fe(III) precipitates generated by Fe(0) electrocoagulation in the presence of groundwater ions

Science.gov (United States)

van Genuchten, C. M.; Pena, J.; Addy, S. E.; Gadgil, A. J.

2012-12-01

Electrocoagulation (EC) using Fe(0) electrodes is an inexpensive and efficient technology capable of removing a variety of contaminants from water supplies. Because of its ease of use and modest electricity and Fe(0) requirements, EC has potential as an arsenic-removal technology for rural South Asia, where millions drink groundwater contaminated by arsenic. In EC, a small external voltage applied to a sacrificial Fe(0) anode in contact with an electrolyte (e.g. pumped groundwater containing arsenic) promotes the oxidative dissolution of Fe ions, which polymerize and create reactive hydrous ferric oxides (HFO) in-situ with a high affinity for binding contaminants. The chemical composition of the electrolyte influences EC performance. For example, major inorganic ions present in groundwater (e.g. Ca, Mg, P, As(V), Si) alter the pathway by which FeO6 oligomers polymerize to form crystalline Fe (oxyhydr)oxide minerals. Because the precipitate structure largely determines properties that govern the efficiency of EC systems (e.g. precipitate reactivity and colloidal stability), it is essential to understand the individual and interdependent structural effects of common groundwater ions. In this work, we integrate Fe K-edge EXAFS spectroscopy with the Pair Distribution Function (PDF) technique to create a detailed description of EC precipitate structure as a function of electrolyte chemistry. EC precipitate samples were generated in a range of individual and combined concentrations of Ca, Mg, P, As(V), and Si, encompassing most of the typical levels found in natural groundwater. Combining complementary EXAFS and PDF techniques with batch uptake experiments and general chemical reasoning, we obtain structural representations of EC precipitates that are inaccessible with any single characterization technique. Our results indicate that the presence of As(V), P, and Si oxyanions promote the formation of nanoscale material bearing similar, but not identical, intermediate

Ion beam synthesis of Fe nanoparticles in MgO and yttria-stabilized zirconia

Science.gov (United States)

Potzger, K.; Reuther, H.; Zhou, Shengqiang; Mücklich, A.; Grötzschel, R.; Eichhorn, F.; Liedke, M. O.; Fassbender, J.; Lichte, H.; Lenk, A.

2006-04-01

To form embedded Fe nanoparticles, MgO(001) and YSZ(001) single crystals have been implanted at elevated temperatures with Fe ions at energies of 100 keV and 110 keV, respectively. The ion fluence was fixed at 6×1016 cm-2. As a result, γ- and α-phase Fe nanoparticles were synthesized inside MgO and YSZ, respectively. A synthesis efficiency of 100% has been achieved for implantation at 1273 K into YSZ. The ferromagnetic behavior of the α-Fe nanoparticles is reflected by a magnetic hyperfine field of 330 kOe and a hysteretic magnetization reversal. Electron holography showed a fringing magnetic field around some, but not all of the particles.

Ion beam synthesis of Fe nanoparticles in MgO and yttria-stabilized zirconia

International Nuclear Information System (INIS)

Potzger, K.; Reuther, H.; Zhou, Shengqiang; Muecklich, A.; Groetzschel, R.; Eichhorn, F.; Liedke, M. O.; Fassbender, J.; Lichte, H.; Lenk, A.

2006-01-01

To form embedded Fe nanoparticles, MgO(001) and YSZ(001) single crystals have been implanted at elevated temperatures with Fe ions at energies of 100 keV and 110 keV, respectively. The ion fluence was fixed at 6x10 16 cm -2 . As a result, γ- and α-phase Fe nanoparticles were synthesized inside MgO and YSZ, respectively. A synthesis efficiency of 100% has been achieved for implantation at 1273 K into YSZ. The ferromagnetic behavior of the α-Fe nanoparticles is reflected by a magnetic hyperfine field of 330 kOe and a hysteretic magnetization reversal. Electron holography showed a fringing magnetic field around some, but not all of the particles

Single-crystalline LiFePO4 nanosheets for high-rate Li-ion batteries.

Science.gov (United States)

Zhao, Yu; Peng, Lele; Liu, Borui; Yu, Guihua

2014-05-14

The lithiation/delithiation in LiFePO4 is highly anisotropic with lithium-ion diffusion being mainly confined to channels along the b-axis. Controlling the orientation of LiFePO4 crystals therefore plays an important role for efficient mass transport within this material. We report here the preparation of single crystalline LiFePO4 nanosheets with a large percentage of highly oriented {010} facets, which provide the highest pore density for lithium-ion insertion/extraction. The LiFePO4 nanosheets show a high specific capacity at low charge/discharge rates and retain significant capacities at high C-rates, which may benefit the development of lithium batteries with both favorable energy and power density.

Simultaneous study of sputtering and secondary ion emission of binary Fe-based alloys

International Nuclear Information System (INIS)

Riadel, M.M.; Nenadovic, T.; Perovic, B.

1976-01-01

The sputtering and secondary ion emission of binary Fe-based alloys of simple phase diagrams have been studied simultaneously. A series FeNi and FeCr alloys in the concentration range of 0-100% have been bombarded by 4 keV Kr + ions in a secondary ion mass spectrometer. The composition of the secondary ions has been analysed and also a fraction of the sputtered material has been collected and analysed by electron microprobe. The surface topography of the etched samples has been studied by scanning electron microscope. The relative sputtering coefficients of the metals have been determined, and the preferential sputtering of the alloying component of lower S have been proved. The etching pictures of samples are in correlation with the sputtering rates. Also the degree of secondary ionization has been calculated from the simultaneously measured ion emission and sputtering data. α + shows the change in the concentration range of the melting point minimum. This fact emphasizes the connection between the physico-chemical properties of alloys and their secondary emission process. From the dependence of the emitted homo- and hetero-cluster ions, conclusions could be shown concerning the production mechanism of small metallic aggregates

Sorption and reduction of selenite on chlorite surfaces in the presence of Fe(II) ions.

Science.gov (United States)

Baik, Min Hoon; Lee, Seung Yeop; Jeong, Jongtae

2013-12-01

The sorption and reduction of selenite on chlorite surfaces in the presence of Fe(II) ions were investigated as a function of pH, Se(IV) concentration, and Fe(II) concentration under an anoxic condition. The sorption of Se(IV) onto chlorite surfaces followed the Langmuir isotherm regardless of the presence of Fe(II) ions in the solution. The Se(IV) sorption was observed to be very low at all pH values when the solution was Fe(II)-free or the concentration of Fe(II) ions was as low as 0.5 mg/L. However, the Se(IV) sorption was enhanced at a pH > 6.5 when the Fe(II) concentration was higher than 5 mg/L because of the increased sorption of Fe(II) onto the chlorite surfaces. XANES (X-ray absorption near edge structure) spectra of the Se K-edge showed that most of the sorbed Se(IV) was reduced to Se(0) by Fe(II) sorbed onto the chlorite surfaces, especially at pH > 9. The combined results of field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) also showed that elemental selenium and goethite were formed and precipitated on the chlorite surfaces during the sorption of selenite. Consequently it can be concluded that Se(IV) can be reduced to Se(0) in the presence of Fe(II) ions by the surface catalytic oxidation of Fe(II) into Fe(III) and the formation of goethite at neutral and particularly alkaline conditions. Thus the mobility of selenite in groundwater is expected to be reduced by the presence of a relatively higher concentration of Fe(II) in subsurface environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Moessbauer-spectroscopic study of structure and magnetism of the exchange-coupled layer systems Fe/FeSn{sub 2}, and Fe/FeSi/Si and the ion-implanted diluted magnetic semiconductor SiC(Fe); Moessbauerspektroskopische Untersuchung von Struktur und Magnetismus der austauschgekoppelten Schichtsysteme Fe/FeSn{sub 2} und Fe/FeSi/Si und des ionenimplantierten verduennten magnetischen Halbleiters SiC(Fe)

Energy Technology Data Exchange (ETDEWEB)

Stromberg, Frank

2009-07-07

In line with this work the structural and magnetic properties of the exchange coupled layered systems Fe/FeSn{sub 2} and Fe/FeSi/Si and of the Fe ion implanted diluted magnetic semiconductor (DMS) SiC(Fe) were investigated. The main measuring method was the isotope selective {sup 57}Fe conversion electron Moessbauer spectroscopy (CEMS), mostly in connection with the {sup 57}Fe tracer layer technique, in a temperature range from 4.2 K to 340 K. Further measurement techniques were X-ray diffraction (XRD), electron diffraction (LEED, RHEED), SQUID magnetometry and FMR (Ferromagnetic Resonance). In the first part of this work the properties of thin AF FeSn{sub 2}(001) films and of the exchange-bias system Fe/FeSn{sub 2}(001) on InSb(001) were investigated. With the application of {sup 57}Fe-tracer layers and CEMS both the Fe-spin structure and the temperature dependence of the magnetic hyperfine field (B{sub hf}) of FeSn{sub 2} could be examined. The evaporation of Fe films on the FeSn{sub 2} films produced in the latter ones a high perpendicular spin component at the Fe/FeSn{sub 2} interface. In some distance from the interface the Fe spins rotate back into the sample plane. Furthermore {sup 57}Fe-CEMS provided a correlation between the absolute value of the exchange field vertical stroke He vertical stroke and the amount of magnetic defects within the FeSn{sub 2}. Temperature dependent CEMS-measurements yielded informations about the spin dynamics within the AF. The transition temperatures T{sub B}{sup *}, which were interpreted as superparamagnetic blocking temperatures, obtain higher values compared to the temperatures T{sub B} of the exchange-bias effect, obtained with magnetometry measurements. The second part of this work deals with the indirect exchange coupling within Fe/FeSi/Si/FeSi/Fe multilayers and FeSi diffusion barriers. The goal was to achieve Fe free Si interlayers. The CEMS results show that starting from a thickness of t{sub FeSi}=10-12 A of the

Thermal Characteristics of Conversion-Type FeOF Cathode in Li-ion Batteries

Directory of Open Access Journals (Sweden)

Liwei Zhao

2017-10-01

Full Text Available Rutile FeOF was used as a conversion-type cathode material for Li-ion batteries. In the present study, 0.6Li, 1.4Li, and 2.7Li per mole lithiation reactions were carried out by changing the electrochemical discharge reaction depth. The thermal characteristics of the FeOF cathode were investigated by thermogravimetric mass spectrometric (TG-MS and differential scanning calorimeter (DSC systems. No remarkable HF release was detected, even up to 700 °C, which indicated a low toxic risk for the FeOF cathode. Changes in the thermal properties of the FeOF cathode via different conversion reaction depths in the associated electrolyte were studied by changing the cathode/electrolyte ratio in the mixture. LiFeOF was found to exothermically react with the electrolyte at about 210 °C. Similar exothermic reactions were found with charged FeOF cathodes because of the irreversible Li ions. Among the products of the conversion reaction of FeOF, Li2O was found to exothermically react with the electrolyte at about 120 °C, which induced the main thermal risk of the FeOF cathode. It suggests that the oxygen-containing conversion-type cathodes have a higher thermal risk than the oxygen-free ones, but controlling the cathode/electrolyte ratio in cells successfully reduced the thermal risk. Finally, the thermal stability of the FeOF cathode was evaluated in comparison with FeF3 and LiFePO4 cathodes.

Differential effects of x-rays and high-energy 56Fe ions on human mesenchymal stem cells.

Science.gov (United States)

Kurpinski, Kyle; Jang, Deok-Jin; Bhattacharya, Sanchita; Rydberg, Bjorn; Chu, Julia; So, Joanna; Wyrobek, Andy; Li, Song; Wang, Daojing

2009-03-01

Stem cells hold great potential for regenerative medicine, but they have also been implicated in cancer and aging. How different kinds of ionizing radiation affect stem cell biology remains unexplored. This study was designed to compare the biological effects of X-rays and of high-linear energy transfer (LET) (56)Fe ions on human mesenchymal stem cells (hMSC). A multi-functional comparison was carried out to investigate the differential effects of X-rays and (56)Fe ions on hMSC. The end points included modulation of key markers such as p53, cell cycle progression, osteogenic differentiation, and pathway and networks through transcriptomic profiling and bioinformatics analysis. X-rays and (56)Fe ions differentially inhibited the cell cycle progression of hMSC in a p53-dependent manner without impairing their in vitro osteogenic differentiation process. Pathway and network analyses revealed that cytoskeleton and receptor signaling were uniquely enriched for low-dose (0.1 Gy) X-rays. In contrast, DNA/RNA metabolism and cell cycle regulation were enriched for high-dose (1 Gy) X-rays and (56)Fe ions, with more significant effects from (56)Fe ions. Specifically, DNA replication, DNA strand elongation, and DNA binding/transferase activity were perturbed more severely by 1 Gy (56)Fe ions than by 1 Gy X-rays, consistent with the significant G2/M arrest for the former while not for the latter. (56)Fe ions exert more significant effects on hMSC than X-rays. Since hMSC are the progenitors of osteoblasts in vivo, this study provides new mechanistic understandings of the relative health risks associated with low- and high-dose X-rays and high-LET space radiation.

SEPARATION OF Fe (III, Cr(III, Cu(II, Ni(II, Co(II, AND Pb(II METAL IONS USING POLY(EUGENYL OXYACETIC ACID AS AN ION CARRIER BY A LIQUID MEMBRANE TRANSPORT METHOD

Directory of Open Access Journals (Sweden)

La Harimu

2010-06-01

Full Text Available Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II  metal ions had been separated using poly(eugenyl oxyacetic acid as an ion carrier by bulk liquid membrane transport method. The effect of pH, polyeugenyl oxyacetic acid ion carrier concentration, nitric acid concentration in the stripping solution, transport time, and metal concentration were optimized. The result showed that the optimum condition for transport of metal ions was at pH 4 for ion Fe(III and at pH 5 for Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions. The carrier volumes were optimum with concentration of 1 x 10-3 M at 7.5 mL for Cr(III, Cu (II,  Ni(II, Co(II ions and at 8.5 mL for Fe(III and Pb(II ions. The concentration of HNO3 in stripping phase was optimum at 2 M for Fe(III and Cu(II ions, 1 M for Cr(III, Ni(II and Co(II ions, and 0.5 M for Pb(II ion. The optimum transport times were 36 h for Fe(III and Co(II ions, and 48 h for Cr(III, Cu (II, Ni(II, and Pb(II ions. The concentration of metal ions accurately transported were 2.5 x 10-4 M for Fe(III and Cr(III ions, and 1 M for Cu (II, Ni(II, Co(II, and Pb(II ions. Compared to other metal ions the transport of Fe(III was the highest with selectivity order of Fe(III > Cr(III > Pb(II > Cu(II > Ni(II > Co(II. At optimum condition, Fe(III ion was transported through the membrane at 46.46%.   Keywords: poly(eugenyl oxyacetic acid, transport, liquid membrane, Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions

Influence of the surface topography, morphology and structure on magnetic properties of ion beam sputtered iron layers, Fe/Cr/Fe- and Fe/MgO/Fe multilayers; Untersuchung der Morphologie und magnetische Eigenschaften von ionenstrahl-gesputterten Eisen-Einzelschichten, Fe/Cr/Fe- und Fe/MgO/Fe-Schichtsystemen

Energy Technology Data Exchange (ETDEWEB)

Steeb, Alexandra

2007-04-05

In this PhD Thesis, the influence of the surface topography, morphology and structure on magnetic properties of ion beam sputtered iron layers on GaAs is examined. To analyze the structure of the produced iron films, low energy electron diffraction and scanning tunneling microscopy is employed. The utilized methods to investigate the magnetic properties are Kerr- and SQUID-magnetometry and ferromagnetic resonance. It is demonstrated that on untreated as well as on presputtered and heated GaAs substrates the sputtered iron films grow epitaxially. The least surface roughness of 1 A exhibit iron films grown on untreated GaAs, while iron films on heated GaAs have the highest roughness of 30 A. The largest crystal anisotropy constant is found for the presputtered GaAs/Fe-System. For this preparation method, two monolayers of iron are determined to be magnetically dead layers. At a film thickness of 100 A, 83% of the value for saturation magnetization of bulk iron are achieved. The small observed FMR-linewidths confirm the good bulk properties of the ion beam sputtered iron. Furthermore, an antiferromagnetic interlayer exchange coupling in sputtered Fe/Cr/Fe-films was achieved. For a thickness of 12 to 17 A of the chrome interlayer, a coupling strength up to 0.2 mJ/m{sup 2} is found. To account for the small coupling strength, a strong intermixing at the interface is assumed. Finally, epitaxial Fe/MgO/Fe/FeMn multilayers are deposited on GaAs. After the structuring, it is possible to detect tunneling processes in the tunneling contacts with current-voltage measurements. The tunnel magneto resistance values of 2% are small, which can be explained by the absence of sharp, well-defined interfaces between the Fe/FeMn and the Fe/MgO interfaces. These results demonstrate, that analog to MBE the ion beam sputtering method realizes good magnetic bulk properties. However, interface sensitive phenomena are weakened because of a strong intermixing at the interfaces. (orig.)

Facile synthesis of Fe4N/Fe2O3/Fe/porous N-doped carbon nanosheet as high-performance anode for lithium-ion batteries

Science.gov (United States)

Zhang, Dan; Li, Guangshe; Yu, Meijie; Fan, Jianming; Li, Baoyun; Li, Liping

2018-04-01

Iron nitrides are considered as highly promising anode materials for lithium-ion batteries because of their nontoxicity, high abundance, low cost, and higher electrical conductivity. Unfortunately, their limited synthesis routes are available and practical application is still hindered by their fast capacity decay. Herein, a facile and green route is developed to synthesize Fe4N/Fe2O3/Fe/porous N-doped carbon nanosheet composite. The size of Fe4N/Fe2O3/Fe particles is small (10-40 nm) and they are confined in porous N-doped carbon nanosheet. These features are conducive to accommodate volume change well, shorten the diffusion distance and further elevate electrical conductivity. When tested as anode material for lithium-ion batteries, a high discharge capacity of 554 mA h g-1 after 100 cycles at 100 mA g-1 and 389 mA h g-1 after 300 cycles at 1000 mA g-1 are retained. Even at 2000 mA g-1, a high capacity of 330 mA h g-1 can be achieved, demonstrating superior cycling stability and rate performance. New prospects will be brought by this work for the synthesis and the potential application of iron nitrides materials as an anode for LIBs.

One-pot synthesis of Fe{sub 3}O{sub 4}/Fe/MWCNT nanocomposites via electrical wire pulse for Li ion battery electrodes

Energy Technology Data Exchange (ETDEWEB)

Lee, Duk-Hee; Seo, Seung-Deok; Lee, Gwang-Hee [School of Civil, Environmental and Architectural Engineering, Korea University, 145, Anam-Ro, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); Hong, Hyun-Seon [Advanced Materials and Processing Center, Institute for Advanced Engineering, Yongin 449-863 (Korea, Republic of); Kim, Dong-Wan, E-mail: dwkim1@korea.ac.kr [School of Civil, Environmental and Architectural Engineering, Korea University, 145, Anam-Ro, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of)

2014-09-01

Highlights: • Synthesis of Fe{sub 3}O{sub 4}/Fe/MWCNT nanocolloids using an electrical wire explosion process. • Electrical connection of Fe{sub 3}O{sub 4} to a current collector by the conducting networks. • Improved electrochemical performance of Fe{sub 3}O{sub 4}/Fe/MWCNT nanocomposite electrodes. - Abstract: Nanocomposites containing Fe{sub 3}O{sub 4}/Fe/multiwalled carbon nanotubes (MWCNT) were prepared via an electrical wire pulse process (a top-down approach) using Fe wire and dispersed, functionalized MWCNT in deionized water (DIW) at room temperature. The structural and electrochemical characteristics of the resulting nanocomposites were investigated in detail. When used as an anode for Li ion batteries, the Fe{sub 3}O{sub 4}/Fe/MWCNT nanocomposites exhibited greater cycle stability and rate performance than plain Fe{sub 3}O{sub 4}/Fe composites, with a capacity of 460 mA h g{sup −1} at a rate of 168 mA g{sup −1} after 50 cycles. The enhanced performance was attributed to superior electrical conductivity and buffering effect of the MWCNTs on volume changes of the anodes. This process is a promising facile method for lithium ion battery anode material synthesis.

Moessbauer studies of 57Fe substitution of Cu ions in superconducting oxides

International Nuclear Information System (INIS)

Saitovitch, E.B.

1988-01-01

Since the discovery of high-T c superconductivity in YBa 2 Cu 3 O 7 oxides several studies of metal ions substitutions were reported. The observed depression on T c without a systematic correlation with the charge and magnetic moment of Cu substituents claims for more detailed information about its local properties as can be revealed by 57 Fe Moessbauer spectroscopy. The results for different iron concentrations combined with modifications of the superconducting transition are discussed concerning the presence of magnetic moments on the Fe ions and the preferential occupation of Cu(1) sites, recently confirmed by neutron and electron diffraction experiments. The oxygen coordination for the different iron species are proposed on the basis of their dependence on Fe concentration, their behavior at high temperatures as well as the electron diffraction and electron microscopy measurements reported for Fe: YBa 2 Cu 3 O 7 samples. (author) [pt

Differential Effects of X-Rays and High-Energy 56Fe Ions on Human Mesenchymal Stem Cells

International Nuclear Information System (INIS)

Kurpinski, Kyle; Jang, Deok-Jin; Bhattacharya, Sanchita; Rydberg, Bjorn; Chu, Julia; So, Joanna; Wyrobek, Andy; Li Song; Wang Daojing

2009-01-01

Purpose: Stem cells hold great potential for regenerative medicine, but they have also been implicated in cancer and aging. How different kinds of ionizing radiation affect stem cell biology remains unexplored. This study was designed to compare the biological effects of X-rays and of high-linear energy transfer (LET) 56 Fe ions on human mesenchymal stem cells (hMSC). Methods and Materials: A multi-functional comparison was carried out to investigate the differential effects of X-rays and 56 Fe ions on hMSC. The end points included modulation of key markers such as p53, cell cycle progression, osteogenic differentiation, and pathway and networks through transcriptomic profiling and bioinformatics analysis. Results: X-rays and 56 Fe ions differentially inhibited the cell cycle progression of hMSC in a p53-dependent manner without impairing their in vitro osteogenic differentiation process. Pathway and network analyses revealed that cytoskeleton and receptor signaling were uniquely enriched for low-dose (0.1 Gy) X-rays. In contrast, DNA/RNA metabolism and cell cycle regulation were enriched for high-dose (1 Gy) X-rays and 56 Fe ions, with more significant effects from 56 Fe ions. Specifically, DNA replication, DNA strand elongation, and DNA binding/transferase activity were perturbed more severely by 1 Gy 56 Fe ions than by 1 Gy X-rays, consistent with the significant G2/M arrest for the former while not for the latter. Conclusions: 56 Fe ions exert more significant effects on hMSC than X-rays. Since hMSC are the progenitors of osteoblasts in vivo, this study provides new mechanistic understandings of the relative health risks associated with low- and high-dose X-rays and high-LET space radiation

LiFePO4 mesocrystals for lithium-ion batteries.

Science.gov (United States)

Popovic, Jelena; Demir-Cakan, Rezan; Tornow, Julian; Morcrette, Mathieu; Su, Dang Sheng; Schlögl, Robert; Antonietti, Markus; Titirici, Maria-Magdalena

2011-04-18

Olivine LiFePO(4) is considered one of the most promising cathode materials for Li-ion batteries. A simple one-step, template-free, low-temperature solvothermal method is developed for the synthesis of urchinlike hierarchical mesocrystals of pristine LiFePO(4) as well as carbon-coated LiFePO(4) composites. Each urchinlike mesocrystal consists of LiFePO(4) sheets self-assembled via a dipolar field in spheres during a solvothermal process under the influence of Cl(-) anions. The obtained primary sheets of LiFePO(4) are single crystalline in nature and can be coated in situ with an amorphous nitrogen-doped carbonaceous layer several nanometers in thickness. To increase the conductivity of the carbon coating, the materials are subjected to further temperature treatment (700 °C) under an inert atmosphere. The lithium storage performance of the pure LiFePO(4) is compared with that of its carbon-coated counterparts. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ion irradiation effects on high purity bcc Fe and model FeCr alloys

International Nuclear Information System (INIS)

Bhattacharya, Arunodaya

2014-01-01

FeCr binary alloys are a simple representative of the reduced activation ferritic/martensitic (F-M) steels, which are currently the most promising candidates as structural materials for the sodium cooled fast reactors (SFR) and future fusion systems. However, the impact of Cr on the evolution of the irradiated microstructure in these materials is not well understood in these materials. Moreover, particularly for fusion applications, the radiation damage scenario is expected to be complicated further by the presence of large quantities of He produced by the nuclear transmutation (∼ 10 appm He/dpa). Within this context, an elaborate ion irradiation study was performed at 500 C on a wide variety of high purity FeCr alloys (with Cr content ranging from ∼ 3 wt.% to 14 wt.%) and a bcc Fe, to probe in detail the influence of Cr and He on the evolution of microstructure. The irradiations were performed using Fe self-ions, in single beam mode and in dual beam mode (damage by Fe ions and co-implantation of He), to separate ballistic damage effect from the impact of simultaneous He injection. Three different dose ranges were studied: high dose (157 dpa, 17 appm He/dpa for the dual beam case), intermediate dose (45 dpa, 57 appm He/dpa for dual beam case) and in-situ low dose (0.33 dpa, 3030 appm He/dpa for the dual beam case). The experiments were performed at the JANNuS triple beam facility and dual beam in situ irradiation facility at CEA-Saclay and CSNSM, Orsay respectively. The microstructure was principally characterized by conventional TEM, APT and EDS in STEM mode. The main results are as follows: 1) A comparison of the cavity microstructure in high dose irradiated Fe revealed strong swelling reduction by the addition of He. It was achieved by a drastic reduction in cavity sizes and an increased number density. This behaviour was observed all along the damage depth, up to the damage peak. 2) Cavity microstructure was also studied in the dual beam high dose

The formation of magnetic silicide Fe3Si clusters during ion implantation

Science.gov (United States)

Balakirev, N.; Zhikharev, V.; Gumarov, G.

2014-05-01

A simple two-dimensional model of the formation of magnetic silicide Fe3Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

The formation of magnetic silicide Fe3Si clusters during ion implantation

International Nuclear Information System (INIS)

Balakirev, N.; Zhikharev, V.; Gumarov, G.

2014-01-01

A simple two-dimensional model of the formation of magnetic silicide Fe 3 Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field

Facile synthesis of Fe-incorporated CuO nanoarrays with enhanced electrochemical performance for lithium ion full batteries

Energy Technology Data Exchange (ETDEWEB)

Heng, Bojun [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Department of Applied Physics, Wuhan University of Science and Technology, Wuhan, 430065 (China); Qing, Chen; Wang, Hai; Sun, Daming; Wang, Bixiao [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Tang, Yiwen, E-mail: ywtang@phy.ccnu.edu.cn [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China)

2015-11-15

CuO nanoarrays (CNAs) and Fe-incorporated CuO nanoarrays (FCNAs) were fabricated by hydrothermal method. Addition of Fe salt to the reaction mixture allowed the introduction of iron oxide onto the CNAs surface, which was characterized by XPS and HRTEM. Introducing Fe ion into reaction precursor significantly affected not only the morphologies of as-prepared products but also their electrochemical performance as anode for lithium ion full battery. The FCNAs electrodes showed higher specific capacity and better capacity retention at different current densities than that of CNAs. - Highlights: • Fe-incorporated CuO nanoarrays were fabricated by hydrothermal method. • Fe salt in reaction mixture leads to iron oxides forming on the surface of CuO. • Fe-incorporating improves the lithium ion battery performance of CuO anodes.

Contribution to 57Fe ion implanted garnet study by Moessbauer effect

International Nuclear Information System (INIS)

Kornilios, N.

1986-11-01

Due to because of their numerous physical properties, garnets are often used in new technologies. In order to improve their properties, ion implantation of inert gases has been proved to be a powerful technique to elaborate bubble memories. Recently it has been shown that high doses implanted ions, chemically reacting with the matrix could give interesting results. If the bulk is completely amorphized after implantation, further annealings can recrystallize it. In this study Y 3 F 5 O 12 , Y 3 Al 5 O 12 and Gd 3 Ga 5 O 12 single crystals were 100 keV implanted with 57 Fe ions at doses ranging between 10 16 and 10 17 ions cm -2 . The iron chemical states were determined thanks to Conversion Electron Moessbauer Spectroscopy (CEMS) and it was shown that the alloying elements of the matrix could influence the nature of the created phases. After thermal treatments the sample superficial layers were characterized using CEMS, grazing angle X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Rutherford Backscattering Spectroscopy (RBS). Different annealing stages were put forward: the oxidation of the implanted iron below 650 0 C and the garnet recrystallization around 850 0 C with some iron substitution in the garnet octahedral and tetraedral sites. The overstoechiometric iron forms particles of mixed oxides (FeAl) 2 O 3 , (FeGa) 2 O 3 or particles of pure Fe 2 O 3 oxide depending on the garnet. For the first time it is proved that after annealing around 1200-1300 0 C a complete rebuilding of the garnet matrix can induce for these oxide particles at room temperature a Morin transition [fr

Ion exchange and electrochemical evaluation of the microporous phosphate Li9Fe7(PO4)10

International Nuclear Information System (INIS)

Becht, Gregory A.; Vaughey, John T.; Britt, Robin L.; Eagle, Cassandra T.; Hwu, Shiou-Jyh

2008-01-01

A new lithium iron(III) phosphate, Li 9 Fe 7 (PO 4 ) 10 , has been synthesized and is currently under electrochemical evaluation as an anode material for rechargeable lithium-ion battery applications. The sample was prepared via the ion exchange reaction of Cs 5 K 4 Fe 7 (PO 4 ) 10 1 in the 1 M LiNO 3 solution under hydrothermal conditions at 200 deg. C. The fully Li + -exchanged sample Li 9 Fe 7 (PO 4 ) 10 2 cannot yet be synthesized by conventional high-temperature, solid-state methods. The parent compound 1 is a member of the Cs 9-x K x Fe 7 (PO 4 ) 10 series that was previously isolated from a high-temperature (750 deg. C) reaction employing the eutectic CsCl/KCl molten salt. The polycrystalline solid 1 was first prepared in a stoichiometric reaction via conventional solid-state method then followed by ion exchange giving rise to 2. Both compounds adopt three-dimensional structures that consist of orthogonally interconnected channels where electropositive ions reside. It has been demonstrated that the Cs 9-x K x Fe 7 (PO 4 ) 10 series possesses versatile ion exchange capabilities with all the monovalent alkali metal and silver cations due to its facile pathways for ion transport. 1 and 2 were subject to electrochemical analysis and preliminary results suggest that the latter can be considered as an anode material. Electrochemical results indicate that Li 9 Fe 7 (PO 4 ) 10 is reduced below 1 V (vs. Li) to most likely form a Fe(0)/Li 3 PO 4 composite material, which can subsequently be cycled reversibly at relatively low potential. An initial capacity of 250 mAh/g was measured, which is equivalent to the insertion of thirteen Li atoms per Li 9+x Fe 7 (PO 4 ) 10 (x = 13) during the charge/discharge process (Fe 2+ + 2e → Fe 0 ). Furthermore, 2 shows a lower reduction potential (0.9 V), by approximately 200 mV, and much better electrochemical reversibility than iron(III) phosphate, FePO 4 , highlighting the value of improving the ionic conductivity of the sample

Argon Ion Irradiation Effect on the Magnetic Properties of Fe-Al2O3 Nano Granular Film

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Setyo Purwanto

2014-10-01

Full Text Available We studied the effect of Argon (Ar ion irradiation on Fe-Al2O3 nanogranular thin film. X-ray diffraction (XRD patterns show that the ion dose might promote the growth of the Fe2O3 phase from an amorphous phase to a crystalline phase. The magnetic and magnetoresistance properties were investigated using a vibrating sample magnetometer (VSM and a four point probe (FPP. The results suggest that percolation concentration occurred at the 0.55 Fe volume fraction and with a maximum magnetoresistance (MR ratio of 3%. The present MR ratio was lower than that of previous results, which might be related to the existence of the α-Fe2O3 phase promoted by Ar ion irradiation. CEMS spectra show ion irradiation induces changes from superparamagnetic characteristics to ferromagnetic ones, which indicates the spherical growth of Fe particles in the Al2O3 matrix.

Moessbauer of phase separation in FeNi multilayers under ion bombardment

Energy Technology Data Exchange (ETDEWEB)

Amaral, L.; Paesano, A.; Brueckman, M.E. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Scorzelli, R.B.; Dominguez, A.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Shinjo, T.; Ono, T.; Hosoito, N. [Kyoto Univ. (Japan). Inst. for Chemical Research

1997-01-01

We investigated the effect of noble gas irradiation (He, Ne, Ar and Xe) on the Fe-Ni multilayers with a very thin modulation and nominal composition in the invar region Fe{sub 0.63} Ni{sub 0.37}. The evaluation of the formation/stability of the Fe-Ni phases formed under irradiation with different ions and doses was followed by conversion electron Moessbauer spectroscopy (CEMS). (author). 21 refs., 4 figs., 2 tabs.; e-mail: scorza at novell.cat.cbpf.br.

Systematic measurements of transient fields for W, Os and Pt ions traversing Fe

International Nuclear Information System (INIS)

Stuchbery, A.E.; Heseltine, T.H.; Anderssen, S.S.; Bolotin, H.H.; Byrne, A.P.; Fabricius, B.; Kibedi, T.

1994-01-01

Transient magnetic fields were measured for W, Os and Pt ions traversing iron hosts with average velocities in the range from approximately 1.6 v 0 to 4.8 v 0 (v 0 = c/137, Bohr velocity). Transient fields for W and Os in Fe are consistent with behaviour found for lighter rare-earth ions and are about 20% stronger than those for Pt in Fe over the majority of the velocity range examined. A measurement was made to confirm that possible heavy-ion beam induced attenuations of the transient field are negligible for low-velocity Pt ions excited by Ni beams. Results are discussed in terms of both empirical and model-based parameterizations of the transient field strength. (orig.)

Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

Science.gov (United States)

Wang, Henan; Zheng, Yang; Li, Yan; Jiang, Chengbao

2017-05-01

Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40-60 nm and Fe2O3/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (Ecorr) and a 10-fold increase in the corrosion current density (icorr) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Fe+ ion irradiation induced changes in structural and magnetic properties of iron films

Directory of Open Access Journals (Sweden)

K. Papamihail

2016-12-01

Full Text Available 490keV Fe+ ion irradiation of 200nm thick Fe films was found to induce both structural and magnetic changes. Both, the lattice constant and the grain size increase as a function of dose and both properties follow the same power law. Irradiation induces a depth dependent magnetic profile consisting of two sublayers. The top Fe sublayer has a magnetic moment higher than that of the Fe before the irradiation whereas the bottom sublayer lower. The two sublayers are connected with the effects of Fe+ irradiation, i.e. the top sublayer with the depth in which mainly radiation damage occurs whereas the bottom one with the implantation of impinging Fe+ ions. The magnetic moments of the two sublayers have a non-monotonous variation with irradiation dose depicting a maximum for the top sublayer and a minimum for the bottom one at 96.2 dpa (‘displacements per atom’. The magnetic moment enhancement/reduction is discussed in relation with the atomic volume variation in the case of atom displacements and/or implantation effects.

Facile synthesis of Fe3O4@PDA core-shell microspheres functionalized with various metal ions: A systematic comparison of commonly-used metal ions for IMAC enrichment.

Science.gov (United States)

Jiang, Jiebing; Sun, Xueni; Li, Yan; Deng, Chunhui; Duan, Gengli

2018-02-01

Metal ions differed greatly in affinity towards phosphopeptides, and thus it is essential to systematically compare the phosphopeptides enrichment ability of different metal ions usually used in the IMAC techniques. In this work, for the first time, eight metal ions, including Nb 5+ , Ti 4+ , Zr 4+ , Ga 3+ , Y 3+ , In 3+ , Ce 4+ , Fe 3+ , were immobilized on the polydopamine (PDA)-coated Fe 3 O 4 (denoted as Fe 3 O 4 @PDA-M n+ ), and systematically compared by the real biosamples, in addition to standard phosphopeptides. Fe 3 O 4 microspheres were synthesized via the solvothermal reaction, followed by self-polymerization of dopamine on the surface. Then through taking advantage of the hydroxyl and amino group of PDA, the eight metal ions were easily adhered to the surface of Fe 3 O 4 @PDA. After characterization, the resultant Fe 3 O 4 @PDA-M n+ microspheres were applied to phosphopeptides enrichment based on the binding affinity between metal ions and phosphopeptides. According to the results, different metal ions presented diverse phosphopeptides enrichment efficiency in terms of selectivity, sensitivity and the enrichment ability from real complex samples, and Fe 3 O 4 @PDA-Nb 5+ and Fe 3 O 4 @PDA-Ti 4+ showed obvious advantages of the phosphopeptides enrichment effect after the comparison. This systematic comparison may provide certain reference for the use and development of IMAC materials in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

Irradiation Effect of Argon Ion on Interfacial Structure Fe(2nm/Si(tsi=0.5-2 nm Multilayer thin Film

Directory of Open Access Journals (Sweden)

S. Purwanto

2010-04-01

Full Text Available Investigation includes formation of interfacial structure of Fe(2nm/Si(tSi= 0.5-2 nm multilayer thin film and the behavior of antiferromagnetic coupling between Fe layers due to Argon ion irradiation was investigated. [Fe(2nm/Si]30 multilayers (MLs with a thickness of Si spacer 0.5 - 2 nanometer were prepared on n-type (100 Si substrate by the helicon plasma sputtering method. Irradiation were performed using 400keV Ar ion to investigate the behavior of magnetic properties of the Fe/Si MLs. The magnetization measurements of Fe/Si MLs after 400keV Ar ion irradiation show the degradation of antiferromagnetic behavior of Fe layers depend on the ion doses. The Magnetoresistance (MR measurements using by Four Point Probe (FPP method also confirm that MR ratio decrease after ion irradiation. X-ray diffraction (XRD patterns indicate that the intensity of a satellite peak induced by a superlattice structure does not change within the range of ion dose. These results imply that the surface of interface structures after ion irradiation become rough although the layer structures are maintained. Therefore, it is considered that the MR properties of Fe/Si MLs also are due to the metallic superlattice structures such as Fe/Cr and Co/Cu MLs.

On the role of Fe{sup 3+} ions in Fe{sub x}O{sub y}/C catalysts for hydrogen production from the photodehydrogenation of ethanol

Energy Technology Data Exchange (ETDEWEB)

Galindo-Hernández, Félix, E-mail: felixgalindo@gmail.com [Universidad Nacional Autónoma de México (U.N.A.M.), A.P. 20-364, México City, D.F. 01000 (Mexico); Instituto Mexicano del Petróleo (I.M.P.), Eje Central Lázaro Cárdenas Norte 152 Col. San Bartolo Atepehuacan, México City, D.F. 07730 (Mexico); ESIQIE, Instituto Politécnico Nacional, Col. Zacatenco, Av. Politécnico s/n, México City, D.F. 07738 (Mexico); Wang, Jin-An; Chen, Lifang [ESIQIE, Instituto Politécnico Nacional, Col. Zacatenco, Av. Politécnico s/n, México City, D.F. 07738 (Mexico); Bokhimi, Xim [Universidad Nacional Autónoma de México (U.N.A.M.), A.P. 20-364, México City, D.F. 01000 (Mexico); Gómez, Ricardo; Pérez-Larios, Alejandro [Department of Chemistry, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, A.P. 55-534, México City, D.F. 09340 (Mexico); Nava Entzana, Noel [Instituto Mexicano del Petróleo (I.M.P.), Eje Central Lázaro Cárdenas Norte 152 Col. San Bartolo Atepehuacan, México City, D.F. 07730 (Mexico)

2013-12-15

Graphical abstract: In Fe{sub x}O{sub y}/C photocatalyts important effect of Fe{sup 3+} ions in the photodehydrogenation of the ethano was noticed. -- Highlights: • Iron oxides supported on carbon are photoactive catalysts. • Photoactivity in dehydrogenation of ethanol depends of the amount of Fe{sup 3+} ions present in the catalysts. • The capacity of UV–vis absorbance by the Fe{sub x}O{sub y}/C catalysts is significantly dependent of the amount of Fe{sup 3+} ions. • A maximum of rate constant, K = 2125 μmol h{sup −1}, was obtained from the sample with 30 wt% Fe. -- Abstract: Fe{sub x}O{sub y}/C photocatalysts at different iron content were prepared by the incipient wet impregnation method and calcined at 773 K. The photocatalysts were characterized by means of nitrogen adsorption–desorption isotherms, surface fractal dimension, non-local density functional theory, X-ray diffraction, Rietveld refinement and UV–vis spectroscopy. The photocatalytic activity was evaluated using the photodehydrogenation of ethanol as a model reaction for the production of hydrogen. The specific surface areas of Fe{sub x}O{sub y}/C substrates, with 15, 20 and 30 wt% iron content, diminished from 638 to 490 m{sup 2}/g, as the iron content increased. X-ray diffraction analysis showed that iron oxides coexist as wustite and magnetite in samples with Fe contents of 15 and 20 wt%; for sample with 30 wt% Fe, wustite, magnetite and hematite phases were observed. The photophysical, textural and structural properties were modified by the hematite phase formed by thermal treatment. The Rietveld refinements denoted changes in occupancy of Fe{sup 3+} and Fe{sup 2+} in Fe{sub x}O{sub y} crystallites. A relationship between the Fe{sup 3+} ions content and the reactivity for the hydrogen production from the photodehydrogenation of ethanol (from 1360 to 2125 μmol h{sup −1}), was evidenced.

Physical and biological studies with protons and HZE particles in a NASA supported research center in radiation health

Science.gov (United States)

Chatterjee, A.; Borak, T. H.

2001-01-01

NASA has established and supports a specialized center for research and training (NSCORT) to specifically address the potential deleterious effects of HZE particles on human health. The NSCORT in radiation health is a joint effort between Lawrence Berkeley National Laboratory (LBNL) and Colorado State University (CSU). The overall scope of research encompasses a broad range of subjects from microdosimetric studies to cellular and tissue responses to initial damage produced by highly energetic protons and heavy charged particles of the type found in galactic cosmic rays (GCR) spectrum. The objectives of the microdosimetry studies are to determine the response of Tissue Equivalent Proportional Counter (TEPC) to cosmic rays using ground based accelerators. This includes evaluation of energy loss due to the escape of high-energy delta rays and increased energy deposition due to the enhanced delta ray production in the wall of the detector. In this report major results are presented for 56Fe at 1000, 740, 600 and 400 MeV/nucleon. An assessment of DNA repair and early development of related chromosomal changes is extremely important to our overall understanding of enhanced biological effectiveness of high LET particle radiation. Results are presented with respect to the fidelity of the rejoining of double strand breaks and the implications of misrejoining. The relationship between molecular and cytogenetic measurements is presented by studying damage processing in highly heterochromatic supernumerary (correction of sypernumerary) X chromosomes and the active X-chromosome. One of the important consequences of cell's inability to handle DNA damage can be evaluated through mutation studies. Part of our goal is the assessment of potential radioprotectors to reduce the mutation yield following HZE exposures, and some promising results are presented on one compound. A second goal is the integration of DNA repair and mutation studies. Results are presented on a direct

Study on tribological behaviors of Fe+ ion implanted in 2024 aluminum alloy

International Nuclear Information System (INIS)

Zhang Aimin; Chen Jianmin; Shi Weidong; Liu Zhenmin

2000-01-01

2024 aluminum alloy was implanted with Fe + ions at a dose of 7x10 16 -3 x 10 17 Fe + /cm 2 . The depth profile of Fe element was investigated by Auger electron spectroscopy (AES). The composition of the surface layer was investigated by XRD with sample-tilting diffraction (STD) mode. The worn out surface was observed by scanning electron microscopy (SEM). Micro-hardness, friction and wear properties have been studied before and after Fe + implantation. An AES analysis shows Fe display Gaussian shape distributions. STD shows Al 5 Fe 2 formed during the implantation. Micro-hardness of surface layer was reduced after implantation, but it did not simply decrease with the increasing implantation doses. The friction and wear tests of implanted and unimplanted samples were carried out on a static-dynamic friction precise measuring apparatus. After implantation, the friction coefficient was reduced from 0.7 to 0.1; the wear resistance was improved remarkably, but decreased with increasing implantation dose. The wear mechanism of the unimplanted sample was adhesive wear, abrasive wear and plastic deformation. The wear reducing effect of Fe + ion induced on 2024 aluminum alloy is mainly attributed to tribooxidation of iron and transfixion of line defect. These two factors prevent the adhesive wear, abrasive wear and plastic deformation of 2024 aluminum alloy

Biomass carbon composited FeS2 as cathode materials for high-rate rechargeable lithium-ion battery

Science.gov (United States)

Xu, Xin; Meng, Zhen; Zhu, Xueling; Zhang, Shunlong; Han, Wei-Qiang

2018-03-01

Pyrite FeS2 has long been used as commercial primary lithium batteries at room temperature. To achieve rechargeable FeS2 battery, biomass-carbon@FeS2 composites are prepared using green and renewable auricularia auricula as carbon source through the process of carbonization and sulfuration. The auricularia auricula has strong swelling characteristics to absorb aqueous solution which can effectively absorb Fe ions into its body. FeS2 homogeneously distributed in biomass carbon matrix performs high electronic and ionic conductivity. The specific capacity of biomass-carbon@FeS2 composites remains 850 mAh g-1 after 80 cycles at 0.5C and 700 mAh g-1 at the rate of 2C after 150 cycles. Biomass-carbon@FeS2 composites exhibit high-rate capacity in lithium-ion battery.

Utilization of fish bone as adsorbent of Fe3+ ion by controllable removal of its carbonaceous component

Science.gov (United States)

Nurhadi, M.; Kusumawardani, R.; Widiyowati, I. I.; Wirhanuddin; Nur, H.

2018-05-01

The performance of fish bone to adsorb Fe3+ ion in solution was studied. Powdered fish bone and carbonized fish bone were used as adsorbent. All absorbents were characterized by X-ray diffraction (XRD), IR spectroscopy, nitrogen adsorption, scanning electron microscopy (SEM) and TG analysis. Powdered fish bone and carbonized fish bone were effective as adsorbent for removing Fe3+ ion in solution. The metal adsorptions of Fe3+ ion were 94 and 98% for powdered fish bone and fish bone which carbonized at 400 and 500 °C.

Pyrene-Phosphonate Conjugate: Aggregation-Induced Enhanced Emission, and Selective Fe3+ Ions Sensing Properties

Directory of Open Access Journals (Sweden)

Sachin D. Padghan

2017-08-01

Full Text Available A new pyrene-phosphonate colorimetric receptor 1 has been designed and synthesized in a one-step process via amide bond formation between pyrene butyric acid chloride and phosphonate-appended aniline. The pyrene-phosphonate receptor 1 showed aggregation-induced enhanced emission (AIEE properties in water/acetonitrile (ACN solutions. Dynamic light scattering (DLS characterization revealed that the aggregates of receptor 1 at 80% water fraction have an average size of ≈142 nm. Field emission scanning electron microscopy (FE-SEM analysis confirmed the formation of spherical aggregates upon solvent evaporation. The sensing properties of receptor 1 were investigated by UV-vis, fluorescence emission spectroscopy, and other optical methods. Among the tested metal ions, receptor 1 is capable of recognizing the Fe3+ ion selectively. The changes in spectral measurements were explained on the basis of complex formation. The composition of receptor 1 and Fe3+ ions was determined by using Job’s plot and found to be 1:1. The receptor 1–Fe3+ complex showed a reversible UV-vis response in the presence of EDTA.

The formation of magnetic silicide Fe{sub 3}Si clusters during ion implantation

Energy Technology Data Exchange (ETDEWEB)

Balakirev, N. [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Zhikharev, V., E-mail: valzhik@mail.ru [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Gumarov, G. [Zavoiskii Physico-Technical Institute of Russian Academy of Sciences, 10/7 Sibirskii trakt st., Kazan 420029 (Russian Federation)

2014-05-01

A simple two-dimensional model of the formation of magnetic silicide Fe{sub 3}Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

Relaxation-Induced Memory Effect of LiFePO4 Electrodes in Li-Ion Batteries.

Science.gov (United States)

Jia, Jianfeng; Tan, Chuhao; Liu, Mengchuang; Li, De; Chen, Yong

2017-07-26

In Li-ion batteries, memory effect has been found in several commercial two-phase materials as a voltage bump and a step in the (dis)charging plateau, which delays the two-phase transition and influences the estimation of the state of charge. Although memory effect has been first discovered in olivine LiFePO 4 , the origination and dependence are still not clear and are critical for regulating the memory effect of LiFePO 4 . Herein, LiFePO 4 has been synthesized by a home-built spray drying instrument, of which the memory effect has been investigated in Li-ion batteries. For as-synthesized LiFePO 4 , the memory effect is significantly dependent on the relaxation time after phase transition. Besides, the voltage bump of memory effect is actually a delayed voltage overshooting that is overlaid at the edge of stepped (dis)charging plateau. Furthermore, we studied the kinetics of LiFePO 4 electrode with electrochemical impedance spectroscopy (EIS), which shows that the memory effect is related to the electrochemical kinetics. Thereby, the underlying mechanism has been revealed in memory effect, which would guide us to optimize two-phase electrode materials and improve Li-ion battery management systems.

Biosorption of Fe (II) and Cd (II) ions from aqueous solution using a ...

African Journals Online (AJOL)

ADOWIE PERE

Biosorption of Fe (II) and Cd (II) ions from aqueous solution using a low cost ... human activities in the environment poses a lot of risk ... ion exchange or reverse osmosis, electrochemical treatment ..... is the adsorption coefficient, n indicates the.

A study on the effects of relativistic heavy charged particles on the cellular microenvironment

Science.gov (United States)

Costes, Sylvain Vincent

This study was done under the National Aeronautics Space Administration (NASA) effort to assess the effect of cosmic radiation on astronauts during a 3 year mission to Mars. Carcinogenesis is known to be induced more efficiently by cosmic radiation. Our attention was turned towards one of the most efficient cosmic particles in inducing cancer, relativistic Fe, and focused in assessing its effect on the cellular microenvironment (ECM). Previous observations on mammary glands were showing irregularities in the immunoreactivity of the ECM protein laminin one hour after whole body irradiation with 1GeV/amu Fe ions for a dose of 0.8 Gy. This effect was not observed after 5 Gy γ-rays exposure. The rapidity of such a change suggested that the effect might be due to a physical event specific to relativistic charged particles (HZE), rather than a biological event. Our study showed that this effect is actually a complex and rapid response of the microenvironment to highly ionizing radiation. It involves a fast disruption of the basement membrane of the ECM induced by the highly localized ionization and reactive oxygen formation around the track of the Fe ion. This disruption triggers further chemical and biological responses involved in the remodeling of the laminin network in the basement membrane. A metalloproteinase is suspected to be the intermediate protease affecting laminin. The HZE effect on the microenvironment was seen in both mouse mammary glands and skin, but the laminin isoforms sensitive to Fe ions were different for each organ, with a clear disruption of laminin-1 network in skin and of laminin-5 in mammary glands. In addition, the laminin receptor integrins seem to be involved in this mechanism, but its contribution is unclear at this point. Finally, such studies suggest a shift from the concept of relative biological effectiveness (RBE) used in classical radiation biology since the effect is only seen with HZE at viable whole body doses. In addition, this

Detailed investigation of Na2.24FePO4CO3 as a cathode material for Na-ion batteries

Science.gov (United States)

Huang, Weifeng; Zhou, Jing; Li, Biao; Ma, Jin; Tao, Shi; Xia, Dingguo; Chu, Wangsheng; Wu, Ziyu

2014-01-01

Na-ion batteries are gaining an increased recognition as the next generation low cost energy storage devices. Here, we present a characterization of Na3FePO4CO3 nanoplates as a novel cathode material for sodium ion batteries. First-principles calculations reveal that there are two paths for Na ion migration along b and c axis. In-situ and ex-situ Fe K-edge X-ray absorption near edge structure (XANES) point out that in Na3FePO4CO3 both Fe2+/Fe3+ and Fe3+/Fe4+ redox couples are electrochemically active, suggesting also the existence of a two-electron intercalation reaction. Ex-situ X-ray powder diffraction data demonstrates that the crystalline structure of Na3FePO4CO3 remains stable during the charging/discharging process within the range 2.0–4.55 V. PMID:24595232

Surface and local electronic structure modification of MgO film using Zn and Fe ion implantation

Science.gov (United States)

Singh, Jitendra Pal; Lim, Weon Cheol; Lee, Jihye; Song, Jonghan; Lee, Ik-Jae; Chae, Keun Hwa

2018-02-01

Present work is motivated to investigate the surface and local electronic structure modifications of MgO films implanted with Zn and Fe ions. MgO film was deposited using radio frequency sputtering method. Atomic force microscopy measurements exhibit morphological changes associated with implantation. Implantation of Fe and Zn ions leads to the reduction of co-ordination geometry of Mg2+ ions in host lattice. The effect is dominant at bulk of film rather than surface as the large concentration of implanted ions resides inside bulk. Moreover, the evidences of interaction among implanted ions and oxygen are not being observed using near edge fine structure measurements.

A new multifunctional Schiff base as a fluorescence sensor for Fe{sup 2+} and F{sup −} ions, and a colorimetric sensor for Fe{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Wan, Chin-Feng [School of Medical Applied Chemistry, Chung Shan Medical University, Taichung City 40201, Taiwan (China); Chang, Ya-Ju; Chien, Chih-Yu; Sie, Yi-Wun; Hu, Ching-Han [Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan (China); Wu, An-Tai, E-mail: antai@cc.ncue.edu.tw [Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan (China)

2016-10-15

A multifunctional Schiff base fluorescent sensor (receptor L) was prepared and its metal ions and anions sensing properties were investigated. Receptor L exhibited an excellent selective fluorescence response toward Fe{sup 2+} and F{sup −}. It also showed colorimetric response (from colorless to yellow) toward Fe{sup 3+} among a series of ions. Moreover, the detection limits of receptor L for Fe{sup 2+} and F{sup −} were determined to be 0.3 ppm and 25.7 ppb, respectively. The two detection limit values were sufficiently low to detect nano-molar concentration of Fe{sup 2+} and F{sup −}.

Uptake of CrO{sub 4}{sup 2-} ions by Fe-treated tri-calcium phosphate

Energy Technology Data Exchange (ETDEWEB)

Serrano G, J.; Ramirez S, J. L.; Bonifacio M, J.; Granados C, F.; Badillo A, V. E., E-mail: juan.serrano@inin.gob.m [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2010-07-01

CrO{sub 4}{sup 2-} ion adsorption of Fe-treated tri-calcium phosphate was studied by batch experiments as a function of contact time, initial concentration of metal ion and temperature. Adsorption results showed that at ph 5.5 and 1.0 x 10{sup -4} M chromium concentration the adsorption capacity of Fe-treated tri-calcium phosphate for CrO{sub 4}{sup 2-} ions was 7.10 x 10{sup -3} mmol/g. Chromium adsorption data on Fe-treated tri-calcium phosphate at various initial concentration fitted the Freundlich isotherm. By temperature studies the thermodynamic parameters {Delta}H{sup 0}, {Delta}G{sup 0} and {Delta}S{sup 0} were estimated and the obtained results showed that the adsorption reaction was endothermic and spontaneous. (Author)

Enhanced lithium-ion storage performance by structural phase transition from two-dimensional rhombohedral Fe_2O_3 to cubic Fe_3O_4

International Nuclear Information System (INIS)

Ren, Yurong; Wang, Jiawei; Huang, Xiaobing; Ding, Jianning

2016-01-01

Highlights: • The rhombohedral Fe_2O_3 transforms to the cubic Fe_3O_4 via a calcination treatment. • Phase structure of anodes has great influences on their electrochemical performances. • Fe_3O_4/reduced graphene oxide shows a high capacity of 825.3 mAh g"−"1 at 50 mA g"−"1. - Abstract: The electrochemical performance of a material varies with its structural phase transition. It is found that the rhombohedral Fe_2O_3 can transform to the cubic Fe_3O_4 via a calcination treatment in a nitrogen atmosphere, and lithium-ion storage performances of Fe_3O_4 get an obvious improvement due to its structural advantages. On the basis of data calculated by X-ray diffraction, the larger unit cell volume as well as the higher void fraction of cubic Fe_3O_4 provides lithium-ions with more transport channels for Li ions diffusion and storage without serious volume change, and thus the cubic Fe_3O_4 delivers an excellent reversible capacity of 921.1 mAh g"−"1 after 15 cycles at the current density of 50 mA g"−"1, which is much higher than 328.3 mAh g"−"1 for the rhombohedral Fe_2O_3. To further enhance the structural stability of electrodes, reduced graphene oxide is introduced. The Fe_3O_4/reduced graphene oxide show an excellent specific capacity of 825.3 mAh g"−"1 after 40 cycles and impressive rate performance of 600 mAh g"−"1 at the current density of 400 mA g"−"1, which are much higher than that of Fe_3O_4 (417 and 300 mAh g"−"1), Fe_2O_3 (137.4 and 95 mAh g"−"1) and Fe_2O_3/reduced graphene oxide (390.1 and 480 mAh g"−"1). These results demonstrate that the structural phase transition and reduced graphene oxide of Fe_3O_4/reduced graphene oxide composites offer unique characteristics suitable for high-performance energy storage application.

Cytogenetic damage in human blood lymphocytes exposed in vitro and in vivo to space-relevant HZE-particles

Science.gov (United States)

Lee, Ryonfa; Nasonova, Elena; Sommer, Sylvester; Hartel, Carola; Ritter, Sylvia

During space missions astronauts are exposed to cosmic radiations which are different from natural background radiation on Earth in both quantity and quality. Dose rate in space environment is at least 100 times higher than that on Earth. In addition, the natural radiation on Earth consists mainly of X-, γ-rays and α-emitters, while in space charged particles from protons to iron ions are predominant. The composition of radiation environment of outer space is well understood, however, due to a lack of data on the biological effects of dose, dose-rate and especially HZE (high charge Z and energy E) particles, large uncertainties exist in estimating the health risks for long-term space mission. To contribute to this issue, we investigated cytogenetic damage induced by heavy charged particles in human lymphocytes, since chromosome aberration yield is a biomarker showing an association with cancer risk. Lymphocytes collected from a healthy donor were irradiated with carbon ions (C-ions) in vitro with various energies (11.4 to 400 MeV/u; LET values 11 to 175 keV/µm) at either UNILAC or SIS facility (GSI, Germany) or exposed to X-rays. Additionally, peripheral blood was obtained from prostate cancer patients, treated with intensity modulated radiation therapy (IMRT) or IMRT combined with C-ion boost. Samples were taken before, during and after the radiotherapy. Chromosome samples were stained with FPG-technique to enable aberration analysis in 1st cycle metaphases. After in vitro exposure to C-ions, RBE values for the induction of chromosome aberrations increased with sampling time. The effect was most pronounced in samples exposed to 175 keV/µm C-ions and can be attributed to a pronounced cell cycle delay of heavily damaged cells. Thus, for a reliable risk assessment, the effect of selective cell cycle delay following particle exposure should be taken into account. M-FISH analysis of selected samples to assess aberration quality revealed higher frequencies of

Slowing down of 1.3-3.5 MeV/u Fe, Kr and I ions in ten metals

Energy Technology Data Exchange (ETDEWEB)

Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Mueller, S.; Raeisaenen, J.; Virtanen, A

2000-09-01

Stopping powers for 1.3-3.5 MeV/u {sup 56}Fe, {sup 80,84}Kr and {sup 127}I ions in Mg, V, Fe, Co, Ni, Cu, Nb, Sn, Ta and Au have been determined by a transmission technique exposing the metallic sample foils to the direct ion beam. No previous data have been published for Mg, V, Fe, Co, Nb, Sn or Ta stopping media with these ion energies. The experimental results are compared with parametrizations of the stopping powers found in the literature (SRIM-2000 and Hubert's parametrization). Discrepancies as high as 21 and 16% are observed for SRIM and Hubert's parametrization, respectively. However, there is agreement between the present results and other experimental data available at corresponding ion velocities for {sup 84}Kr and {sup 56}Fe in Ni, Cu, and Au.

Ion-beam mixing and solid-state reaction in Zr-Fe multilayers

International Nuclear Information System (INIS)

Paesano, A. Jr.; Motta, A.T.; Birtcher, R.C.; Ryan, E.A.; Teixeira, S.R.; Bruckmann, M.E.; Amaral, L.

1997-01-01

Vapor-deposited Zr-Fe multilayered thin films with various wavelengths and of overall composition either 50% Fe or Fe-rich up to 57% Fe were either irradiated with 300 keV Kr ions at temperatures from 25 K to 623 K to fluences up to 2 x 10 16 cm -2 , or simply annealed at 773 K in-situ in the Intermediate Voltage Electron microscope At Argonne National Laboratory. Under irradiation, the final reaction product is the amorphous phase in all cases studied, but the dose to amorphization depends on the temperature and on the wavelength. In the purely thermal case (annealing at 773 K), the 50-50 composition produces the amorphous phase but for the Fe-rich multilayers the reaction products depend on the multilayer wavelength. For small wavelength, the amorphous phase is still formed, but at large wavelength the Zr-Fe crystalline intermetallic compounds appear. These results are discussed in terms of existing models of irradiation kinetics and phase selection during solid state reaction

Magnetization, magnetic susceptibility, effective magnetic moment of Fe3+ ions in Bi25FeO39 ferrite

International Nuclear Information System (INIS)

Zatsiupa, A.A.; Bashkirov, L.A.; Troyanchuk, I.O.; Petrov, G.S.; Galyas, A.I.; Lobanovsky, L.S.; Truhanov, S.V.

2014-01-01

Magnetic susceptibility for ferrite Bi 25 FeO 39 is measured at 5–950 K in the magnetic field of 0.86 T. It is shown that Bi 25 FeO 39 is paramagnetic in the temperature range 5−950 K. The saturation magnetization is equal to 5.04μ B per formula unit at 5 K in a magnetic field of 10 T. It is found that at 5−300 K the effective magnetic moment of Fe 3+ ions in Bi 25 FeO 39 is equal to 5.82μ B . - Graphical abstract: The dependence of the magnetization (n, μ B ) on the magnetic field for one formula unit of Bi 25 FeO 39 at 5 K. - Highlights: • Magnetic susceptibility for Bi 25 FeO 39 is measured at 5–950 K in the magnetic field of 0.86 T. • It is shown that Bi 25 FeO 39 is paramagnetic in the temperature range 5−950 K. • The saturation magnetization is equal to 5.04μ B per formula unit at 5 K in a magnetic field of 10 T

Band-gap tuning and magnetic properties of heterovalent ions (Ba, Sr and Ca) substituted BiFeO_3 nanoparticles

International Nuclear Information System (INIS)

Chauhan, Sunil; Kumar, Manoj; Katyal, S. C.

2016-01-01

A Comparative study of heterovalent Ba, Sr and Ca ions substitution on the structural, vibrational, optical and magnetic properties of BiFeO_3 nanoparticles was carried out. The distorted rhombohedral structure was confirmed from both X-ray diffraction and Raman spectroscopy techniques in pure BiFeO_3 and Bi_0_._8_5A_0_._1_5FeO_3 (A= Ba, Sr and Ca) samples. UV-Visible spectroscopy results show that the band-gap of BiFeO_3 nanoparticles can be tuned by heterovalent ions substitution from 2.12 eV for BiFeO_3 to 2.10, 2.06 and 2.03 eV for Ca, Sr and Ba substituted BiFeO_3 nanoparticles respectively. The magnetic measurements indicate enhancement in magnetization for heterovalent A"2"+ substituted BiFeO_3 samples and the magnetization increases with increase of ionic radius of the substituted ions.

The local structure and magnetic interactions between Fe3+ and V4+ ions in lithium–phosphate glasses

International Nuclear Information System (INIS)

Andronache, Constantin I.

2012-01-01

Electron Paramagnetic Resonance (EPR) provides a useful tool not only as a probe of local structure and short range order in glasses, but also of magnetic interactions in the glasses containing suitable magnetic ions. We have analyzed the spectra of xFe 2 O 3 ·(100 − x)[P 2 O 5 ·Li 2 O] and x(Fe 2 O 3 ·V 2 O 5 )·(100 − x)[P 2 O 5 ·Li 2 O] glass systems, with 0 2 O 5 ·Li 2 O] stands for 50Li 2 O·50P 2 O 5 glass composition. For samples x > 50 mol % a study indicates the presence of crystalline α Fe 2 O 3 in the glasses. Observed spectra have resonance lines centered at g ∼ 4.3 and g ∼ 2.0 typical for Fe 3+ and V 4+ ions present in the oxide glasses. For low contend of transition metal (TM) oxides (Fe 2 O 3 or V 2 O 5 ·Fe 2 O 3 ) the spectra present a hyperfine structure typical for isolated V 4+ ions. With the increasing of TM content, the EPR absorption signal showing hyperfine structure superposed by a broad line without hyperfine structure characteristic for clustered ions. At high TM content, the vanadium hyperfine structure disappears and only the broad line can be observed in the spectra. -- Highlights: ► Lithium phosphate glass with Fe and V ions were investigated by means of EPR. ► The composition dependence of line intensity were investigated. ► The spin Hamiltonian parameters for VO 2+ were evaluated.

Microstructure and tribology of ion-mixed Fe/Ti/C multilayers on AISI 304 stainless steel

International Nuclear Information System (INIS)

Nastasi, M.; Hirvonen, J.P.; Zocco, T.G.; Jervis, T.R.

1991-01-01

A multilayered Fe/Ti/C structure consisting of eleven alternating sublayers, four Fe, four Ti and three C, was ion mixed on an AISI 304 stainless steel substrate with 400 keV Xe 2+ . Complete mixing was observed after an irradiation of 1x10 17 Xe/cm 2 at 550degC. Electron diffraction revealed the formation of the compounds TiC and Fe 3 C and a small amount of an amorphous phase. Some samples were given a second irradiation with 5x10 15 Xe/cm 2 at 0degC. The phases present following the second irradiation were TiC, α-Fe and an amorphous phase. Tribological and nanoindentation measurements revealed that both types of samples possessed similar hardness and friction properties. The ion mixed samples possessed an increased hardness and a decreased friction coefficient relative to untreated polished stainless-steel substrate. However, the wear life of the hot ion mixed sample was consistently longer than the wear life of the sample processed at both 550 and 0degC. These results are explained by differences in adhesive wear which result from differences in the chemical reactivity of the phases formed during ion beam processing. (orig.)

Storage and Effective Migration of Li-Ion for Defected β-LiFePO4 Phase Nanocrystals.

Science.gov (United States)

Guo, Hua; Song, Xiaohe; Zhuo, Zengqing; Hu, Jiangtao; Liu, Tongchao; Duan, Yandong; Zheng, Jiaxin; Chen, Zonghai; Yang, Wanli; Amine, Khalil; Pan, Feng

2016-01-13

Lithium iron phosphate, a widely used cathode material, crystallizes typically in olivine-type phase, α-LiFePO4 (αLFP). However, the new phase β-LiFePO4 (βLFP), which can be transformed from αLFP under high temperature and pressure, is originally almost electrochemically inactive with no capacity for Li-ion battery, because the Li-ions are stored in the tetrahedral [LiO4] with very high activation barrier for migration and the one-dimensional (1D) migration channels for Li-ion diffusion in αLFP disappear, while the Fe ions in the β-phase are oriented similar to the 1D arrangement instead. In this work, using experimental studies combined with density functional theory calculations, we demonstrate that βLFP can be activated with creation of effective paths of Li-ion migration by optimized disordering. Thus, the new phase of βLFP cathode achieved a capacity of 128 mAh g(-1) at a rate of 0.1 C (1C = 170 mA g(-1)) with extraordinary cycling performance that 94.5% of the initial capacity retains after 1000 cycles at 1 C. The activation mechanism can be attributed to that the induced disorder (such as FeLiLiFe antisite defects, crystal distortion, and amorphous domains) creates new lithium migration passages, which free the captive stored lithium atoms and facilitate their intercalation/deintercalation from the cathode. Such materials activated by disorder are promising candidate cathodes for lithium batteries, and the related mechanism of storage and effective migration of Li-ions also provides new clues for future design of disordered-electrode materials with high capacity and high energy density.

A single low dose of Fe ions can cause long-term biological responses in NL20 human bronchial epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Cao, Qianlin; Wang, Jingdong; Cao, Jianping; Yang, Hongying [Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, School of Radiation Medicine and Protection, Suzhou, Jiangsu (China); Liu, Wei [Soochow University, Department of Radiotherapy and Oncology, Second Affiliated Hospital, Suzhou, Jiangsu (China)

2018-03-15

Space radiation cancer risk may be a potential obstacle for long-duration spaceflight. Among all types of cancer space radiation may induce, lung cancer has been estimated to be the largest potential risk. Although previous animal study has shown that Fe ions, the most important contributor to the total dose equivalent of space radiation, induced a higher incidence of lung tumorigenesis per dose than X-rays, the underlying mechanisms at cellular level remained unclear. Therefore, in the present study, we investigated long-term biological changes in NL20 human bronchial epithelial cells after exposure to Fe ion or X-ray irradiation. We found that compared with sham control, the progeny of NL20 cells irradiated with 0.1 Gy of Fe ions showed slightly increased micronucleus formation, significantly decreased cell proliferation, disturbed cell cycle distribution, and obviously elevated intracellular ROS levels accompanied by reduced SOD1 and SOD2 expression, but the progeny of NL20 cells irradiated with 0.9 Gy of X-rays did not show any significant changes. More importantly, Fe ion exposure caused much greater soft-agar colony formation than X-rays did in the progeny of irradiated NL20 cells, clearly suggesting higher cell transformation potential of Fe ions compared with X-rays. These data may shed the light on the potential lung tumorigenesis risk from Fe ion exposure. In addition, ATM inhibition by Ku55933 reversed some of the changes in the progeny of Fe ion-irradiated cells but not others such as soft-agar colony formation, suggesting complex processes from DNA damage to carcinogenesis. These data indicate that even a single low dose of Fe ions can induce long-term biological responses such as cell transformation, etc., suggesting unignorable health risk from space radiation to astronauts. (orig.)

Effect of swift heavy ion-irradiation on Cr/Fe/Ni multilayers

International Nuclear Information System (INIS)

Gupta, Ratnesh; Gupta, Ajay; Avasthi, D.K.; Principi, G.; Tosello, C.

1999-01-01

A multilayer film having overall composition Fe 50 Cr 25 Ni 25 , was irradiated successively by 80 MeV Si ions and Ag ions of 150 and 200 MeV energy. The energy deposited in the multilayer in the form of electronic excitations results in significant modification at the interfaces. The interfacial roughness increases in the system after the irradiations as revealed by X-ray reflectivity measurement. Moessbauer measurements provide evidence of intermixing after the irradiation by 200 MeV Ag ions. Comparison of heavy ion irradiated multilayer has been done with annealed and low energy ion irradiated samples. Results suggest that the phases formed at the interfaces of iron as a result of electronic energy loss are similar to those in the cases of thermal diffusion and keV energy ion beam irradiation

Photoionization and electron-ion recombination of Fe XVII for high temperature plasmas

International Nuclear Information System (INIS)

Nahar, Sultana N.

2012-01-01

Earlier studies on electron-ion recombination of Fe XVII, e+FeXVIII→FeXVII, concentrated on low temperature region. However, due to its higher abundance, recombination in the high temperature region is of great importance. Total and level-specific recombination cross sections and rates of Fe XVII are presented from the detailed study in the high temperature. The calculations were carried out using the unified method which incorporates both the radiative recombination (RR) and dielectronic recombination (DR) including the interference effects. The method also yields self-consistent set of recombination rates and photoionization cross sections. Unified method is implemented through relativistic Breit-Pauli R-matrix (BPRM) method and close coupling (CC) approximation. For the details of the high energy and high temperature features a CC wave function expansion consisting of 60 levels from n=2 and 3 complexes of the core Fe XVIII was considered. Earlier study included core excitations to n=2 levels only. It is found that the resonances due to core excitations to n=3 levels are much more extensive and stronger than those to n=2 levels and increase the recombination considerably in the high temperature region. While earlier study of 3-level calculations agree very well with the experimentally derived low temperature recombination, the high temperature rate shows a broad peak at about 5×10 6 K, near the maximum abundance of the ion, due to dominance of DR via PEC (photo-excitation-of-core) resonances of n=3 levels. Level-specific recombination rate coefficients, which include both the RR and DR, are presented for 454 levels (n≤10, l≤9, 0 ≤J≤8 with even and odd parities) of Fe XVII. This is the first large-scale BPRM calculations for recombination of a complex atomic system beyond He- and Li-like ions. The results are expected to be accurate with 10-20% uncertainty and provide accurate modelings of ultraviolet to X-ray spectra.

Preparation and Characterisation of LiFePO4/CNT Material for Li-Ion Batteries

Directory of Open Access Journals (Sweden)

Rushanah Mohamed

2011-01-01

Full Text Available Li-ion battery cathode materials were synthesised via a mechanical activation and thermal treatment process and systematically studied. LiFePO4/CNT composite cathode materials were successfully prepared from LiFePO4 material. The synthesis technique involved growth of carbon nanotubes onto the LiFePO4 using a novel spray pyrolysis-modified CVD technique. The technique yielded LiFePO4/CNT composite cathode material displaying good electrochemical activity. The composite cathode exhibited excellent electrochemical performances with 163 mAh/g discharge capacity with 94% cycle efficiency at a 0.1 C discharge rate in the first cycle, with a capacity fade of approximately 10% after 30 cycles. The results indicate that carbon nanotube addition can enable LiFePO4 to display a higher discharge capacity at a fast rate with high efficiency. The research is of potential interest for the application of carbon nanotubes as a new conducting additive in cathode preparation and for the development of high-power Li-ion batteries for hybrid electric vehicles.

High-capacity FeTiO3/C negative electrode for sodium-ion batteries with ultralong cycle life

Science.gov (United States)

Ding, Changsheng; Nohira, Toshiyuki; Hagiwara, Rika

2018-06-01

The development of electrode materials which improve both the energy density and cycle life is one of the most challenging issues facing the practical application of sodium-ion batteries today. In this work, FeTiO3/C nanoparticles are synthesized as negative electrode materials for sodium-ion batteries. The electrochemical performance and charge-discharge mechanism of the FeTiO3/C negative electrode are investigated in an ionic liquid electrolyte at 90 °C. The FeTiO3/C negative electrode delivers a high reversible capacity of 403 mAh g-1 at a current rate of 10 mA g-1, and exhibits high rate capability and excellent cycling stability for up to 2000 cycles. The results indicate that FeTiO3/C is a promising negative electrode material for sodium-ion batteries.

PVC-membrane potentiometric sensors based on a recently synthesized Schiff base for Fe(III ion

Directory of Open Access Journals (Sweden)

S. Yousef Ebrahimipur

2012-12-01

Full Text Available A potentiometric iron sensor based on the use 3-(2-diethylamino-ethylimino-1,3-dihydro-indol-2-one (DEDIO as an ionophore in poly(vinyl chloride (PVC matrix, is reported. The plasticized membrane sensor exhibits a Nernstian response for Fe(III ions over a wide concentration range (2.0 × 10-6 - 5.0 × 10-2 M with a super Nernstian slope of 26(plus or minus 1 mV per decade. It has a fast response time of less than 12 s and can be used for ten weeks without any considerable divergences in its potentials the electrode can be used in the pH range 4.5-8.0. The proposed sensor shows fairly good discriminating ability towards Fe(III ion in comparison with a large number of alkali, alkaline earth, transition and heavy metal ions. The sensor was used as indicator electrode in potentiometric titration of Fe(III ions vs. EDTA.DOI: http://dx.doi.org/10.4314/bcse.v26i1.7

Measurement of total charge changing cross-section for 5 A GeV Si14+ ions in polyethylene and CR39 combined medium

International Nuclear Information System (INIS)

Gupta, R.; Kumar, A.

2013-01-01

Interaction of high energy heavy ions (HZE) in various media is a field of great interest in many aspects of fundamental and applied sciences, detection of cosmic rays, shielding design for space-vehicles and hadron therapy for cancer treatment etc

Enhancement of oxygen reduction at Fe tetrapyridyl porphyrin by pyridyl-N coordination to transition metal ions

International Nuclear Information System (INIS)

Maruyama, Jun; Baier, Claudia; Wolfschmidt, Holger; Bele, Petra; Stimming, Ulrich

2012-01-01

One of the promising candidates as noble-metal-free electrode catalysts for polymer electrolyte fuel cells (PEFCs) is a carbon material with nitrogen atoms coordinating iron ions embedded on the surface (Fe-N x moiety) as the active site, although the activity is insufficient compared to conventional platinum-based electrocatalysts. In order to obtain fundamental information on the activity enhancement, a simple model of the Fe-N x active site was formed by adsorbing 5,10,15,20-Tetrakis(4-pyridyl)-21H,23H-porphine iron(III) chloride (FeTPyPCl) on the basal plane of highly oriented pyrolytic graphite (HOPG), and cathodic oxygen reduction was investigated on the surface in 0.1 M HClO 4 . The catalytic activity for oxygen reduction was enhanced by loading transition metal ions (Co 2+ , Ni 2+ , Cu 2+ ) together with FeTPyPCl. The X-ray photoelectron spectrum of the surface suggested that the metal was coordinated by the pyridine-N. The enhancement effect of the transition metals was supported by two different measurements: oxygen reduction at HOPG in 0.1 M HClO 4 dissolving FeTPyPCl and the metal ions; oxygen reduction in 0.1 M HClO 4 at the subsequently well-rinsed and dried HOPG. The ultraviolet–visible spectrum for the solution also suggested the coordination between the pyridyl-N and the metal ions. The oxygen reduction enhancement was attributed to the electronic interaction between the additional transition metal and the Fe center of the porphyrin through the coordination bonds. These results implied that the improvement of the activity of the noble-metal-free catalyst would be possible by the proper introduction of the transition metal ions around the active site.

Glow-peak stability in 6LiF:Mg, Ti (TLD-600) exposed to a Fe-ion beam

International Nuclear Information System (INIS)

Yasuda, Hiroshi

2001-01-01

The stability of glow peaks in 6 LiF:Mg, Ti (TLD-600) exposed to a high-energy Fe-ion beam was examined in comparison to 137 Cs γ-ray irradiation under changing annealing conditions. The peak areas induced by the Fe ions were much smaller than those by γ-rays. The sizes and positions of peaks 3-5 in Fe-ion irradiated samples were hardly changed after post-annealing at 100 deg C x 30 min, regardless of the pre-annealing conditions (fast quenching or subsequent pre-annealing at 100 deg C x 2 h). Whereas, the peaks in γ-ray irradiated samples were notably affected by post-annealing; the peak positions and peak-area sizes changed in different ways depending on the pre-annealing conditions. The effects of post-annealing on peak 6 were identical for Fe ions and γ-rays. These facts suggest that peaks 3-5 in TLD-600 comprised both stable and unstable luminescent centers, and that the latter part would be easily depleted in highly dense ionization. (author)

Fabrication of γ-Fe2O3 Nanoparticles by Solid-State Thermolysis of a Metal-Organic Framework, MIL-100(Fe, for Heavy Metal Ions Removal

Directory of Open Access Journals (Sweden)

Shengtao Hei

2014-01-01

Full Text Available Porous γ-Fe2O3 nanoparticles were prepared via a solid-state conversion process of a mesoporous iron(III carboxylate crystal, MIL-100(Fe. First, the MIL-100(Fe crystal that served as the template of the metal oxide was synthesized by a low-temperature (<100°C synthesis route. Subsequently, the porous γ-Fe2O3 nanoparticles were fabricated by facile thermolysis of the MIL-100(Fe powders via a two-step calcination treatment. The obtained γ-Fe2O3 was characterized by X-ray diffraction (XRD, N2 adsorption, X-ray photoelectron spectroscopy (XPS, and scanning electron microscopy (SEM techniques, and then used as an adsorbent for heavy metal ions removal in water treatment. This study illustrates that the metal-organic frameworks may be suitable precursors for the fabrication of metal oxides nanomaterials with large specific surface area, and the prepared porous γ-Fe2O3 exhibits a superior adsorption performance for As(V and As(III ions removal in water treatment.

Effect of argon ion etching on the magnetic properties of FeCoB films

Energy Technology Data Exchange (ETDEWEB)

Zhu, Junwei; Zhou, Kan; Yang, Yi; Tang, Dongming; Zhang, Baoshan, E-mail: malab@nju.edu.cn; Lu, Mu; Lu, Huaixian

2015-01-15

In this paper, a new method to modify Ta underlayers by an argon ion etching technology is introduced. Surface roughness of Ta underlayers, as well as soft magnetic properties of post-deposited FeCoB films can be improved by applying a proper ion etching process. The reduction of magnetic coercivity of FeCoB films deposited on the modified Ta underlayers is attributed to the improvement of interfacial roughness, which can reduce magnetic ripples in magnetic films. The microwave damping linewidth of magnetic films is also found to be related to the interfacial roughness. Ta underlayers modified by the ion etching can reduce the influence of two-magnon scattering effect, and thus tune microwave properties of magnetic films. All the results prove that argon ion etching is an effective way to tailor magnetic properties of magnetic films. - Highlights: • We believe that our method to tune the magnetic film properties will be interesting for general readers of Journal of Magnetism and Magnetic Materials. • In the paper, argon ion etching is applied to the Ta underlayer before the FeCoB film is deposited on it. • The modified interface roughness has effectively improved the magnetic properties, including the static magnetic and microwave performance. • The method is valuable for other underlayer/magnetic film systems.

Slowing down of 1.3-3.5 MeV/u Fe, Kr and I ions in ten metals

CERN Document Server

Alanko, T; Kylloenen, V; Müller, S; Raeisaenen, J; Virtanen, A

2000-01-01

Stopping powers for 1.3-3.5 MeV/u sup 5 sup 6 Fe, sup 8 sup 0 sup , sup 8 sup 4 Kr and sup 1 sup 2 sup 7 I ions in Mg, V, Fe, Co, Ni, Cu, Nb, Sn, Ta and Au have been determined by a transmission technique exposing the metallic sample foils to the direct ion beam. No previous data have been published for Mg, V, Fe, Co, Nb, Sn or Ta stopping media with these ion energies. The experimental results are compared with parametrizations of the stopping powers found in the literature (SRIM-2000 and Hubert's parametrization). Discrepancies as high as 21 and 16% are observed for SRIM and Hubert's parametrization, respectively. However, there is agreement between the present results and other experimental data available at corresponding ion velocities for sup 8 sup 4 Kr and sup 5 sup 6 Fe in Ni, Cu, and Au.

Gold Nanoparticle-based Surface-enhanced Raman Scattering Fe(III) Ion Sensor

International Nuclear Information System (INIS)

Ly, Nguyen Hoang; Joo, Sang-Woo; Cho, Kwang Hwi

2015-01-01

We performed density functional theory (DFT) calculations of 4-aminobenzo-15-crown-5 (4AB15C5) in conjugation with 4-mercaptobenzoic acid (4MCB) with the polarizable continuum model (PCM) while considering the aqueous media. After specific binding of the ferric ion onto the 4MCB.4AB15C5 compound, the Raman frequencies and intensities were estimated by DFT calculations with the PCM. It was predicted that the Raman intensities became significantly increased upon binding of the ferric ion. 4MCB.4AB15C5 could be assembled on gold nanoparticles (AuNPs) via the cleavage of the thiol bond. Colorimetric and UV.Vis absorption spectroscopy indicated that AuNPs became significantly aggregated in the presence of 1.10 mM of the ferric ion. Surface-enhanced Raman scattering (SERS) of 4MCB.4AB15C5 was used to identify the dissimilar spectral behaviors that yield a difference in intensity in the presence of the ferric ion. These changes were not observed in the other biological ions Zn 2+ , Mn 2+ , Fe 2+ , Na + , K + , Ca 2+ , Mg 2+ , NH 4+ , and Co 2+ . This study indicated that 4AB15C5 could be used to detect ferric ions in aqueous AuNP solutions by a combined method of colorimetric, UV.Vis absorption, and Raman spectroscopy. AuNPs.[4MCB. 4AB15C5] can thus be utilized as a selective turn-on sensor to Fe3 + in aqueous solutions above 1 mM.

THE INFLUENCES OF Fe(III ION and Fe(OH3 COLLOID ON THE PHOTODEGRADATION of p-CHLOROPHENOL CATALYZED BY TiO2

Directory of Open Access Journals (Sweden)

Endang Tri Wahyuni

2010-06-01

Full Text Available The influences of ionic Fe(III and colloidal Fe(OH3 on the effectiveness of p-chlorophenol photodegradation catalyzed by TiO2 has been studied. Photodegradation was carried out in a batch system by irradiating a suspension of TiO2, p-chlorophenol, and Fe(III as ionic or colloidal forms, using UV lamp for a period of time accompanied by magnetic stirring. Concentration of photodegraded p-chlorophenol was calculated by subtracting the initial concentration with that of undegraded p-chlorophenol. Concentration of undegraded p-chlorophenol was determined by gas chromatography. In this study, TiO2 mass and the photodegradation time were optimized. The influences of concentration of Fe(III solution, mass of Fe(OH3, and pH of the solution have also been systematically studied. The research results showed that the presence of Fe(III ions improved the effectiveness of photocatalytical degradation of p-chlorophenol, which was proportional to the concentrations of Fe(III ion. In contrast, the increasing mass of Fe(OH3 led to a decrease in the degree of p-chlorophenol photodegradation. Furthermore, it was observed that increasing pH of the solution resulted in a decrease in the photodegradation of p-chlorophenol. This phenomena may be due to the different species of TiO2 available at the surface of photocatalyst and of ionic Fe(III and colloidal Fe(OH3 in the solution resulted from the pH alteration. The highest photodegradation degree, ca. 80 % was obtained when 20 mg of TiO2 was applied in the photodegradation of 50 mL of 100 ppm p-chlorophenol solution in the presence of 100 ppm Fe3+ irradiated by UV-light for 25 hours.    Keywords: p-chlorophenol photodegradation, TiO2, Fe(III species

Adsorption of Nitrite and Nitrate Ions from an Aqueous Solution by Fe-Mg-Type Hydrotalcites at Different Molar Ratios.

Science.gov (United States)

Ogata, Fumihiko; Nagai, Noriaki; Kariya, Yukine; Nagahashi, Eri; Kobayashi, Yuhei; Nakamura, Takehiro; Kawasaki, Naohito

2018-01-01

In this study, we prepared Fe-Mg-type hydrotalcites (Fe-HT3.0 and Fe-HT5.0) with different molar ratios and evaluated their adsorption capability for nitrite and nitrate ions from aqueous solution. Fe-HT is a typical hydrotalcite-like layered double hydroxide. Adsorption isotherms, as well as the effects of contact time and pH were investigated, and it was found that Fe-HT can adsorb larger amounts of nitrite and nitrate ions than Al-HT (normal-type hydrotalcite). Adsorption isotherm data were fitted to both Freundlich (correlation coefficient: 0.970-1.000) and Langmuir (correlation coefficient: 0.974-0.999) equations. Elemental analysis and binding energy of Fe-HT surface before and after adsorption indicated that the adsorption mechanism was related to the interaction between the adsorbent surface and anions. In addition, the ion exchange process is related to the adsorption mechanism. The adsorption amount increased with increasing temperature (7-25°C). The experimental data fit the pseudo-second-order model better than the pseudo-first-order model. The effect of pH on adsorption was not significant, which suggested that Fe-HT could be used over a wide pH range (4-12). These results indicate that Fe-HT is a good adsorbent for the removal of nitrite and nitrate ions from aqueous solution.

Atomistic Insights into FeF3 Nanosheet: An Ultrahigh-Rate and Long-Life Cathode Material for Li-Ion Batteries.

Science.gov (United States)

Yang, Zhenhua; Zhao, Shu; Pan, Yanjun; Wang, Xianyou; Liu, Hanghui; Wang, Qun; Zhang, Zhijuan; Deng, Bei; Guo, Chunsheng; Shi, Xingqiang

2018-01-24

Iron fluoride with high operating voltage and theoretical energy density has been proposed as a high-performance cathode material for Li-ion batteries. However, the inertness of pristine bulk FeF 3 results in poor Li kinetics and cycling life. Developing nanosheet-based electrode materials is a feasible strategy to solve these problems. Herein, on the basis of first-principles calculations, first the stability of FeF 3 (012) nanosheet with different atomic terminations under different environmental conditions was systematically studied, then the Li-ion adsorption and diffusion kinetics were thoroughly probed, and finally the voltages for different Li concentrations were given. We found that F-terminated nanosheet is energetically favorable in a wide range of chemical potential, which provide a vehicle for lithium ion diffusion. Our Li-ion adsorption and diffusion kinetics study revealed that (1) the formation of Li dimer is the most preferred, (2) the Li diffusion energy barrier of Li dimer is lower than isolated Li atom (0.17 eV for Li dimer vs 0.22 eV for Li atom), and (3) the diffusion coefficient of Li is 1.06 × 10 -6 cm 2 ·s -1 , which is orders of magnitude greater than that of Li diffusion in bulk FeF 3 (10 -13 -10 -11 cm 2 ·s -1 ). Thus, FeF 3 nanosheet can act as an ultrahigh-rate cathode material for Li-ion batteries. More importantly, the calculated voltage and specific capacity of Li on the FeF 3 (012) nanosheet demonstrate that it has a much more stable voltage profile than bulk FeF 3 for a wide range of Li concentration. So, few layers FeF 3 nanosheet provides the desired long-life energy density in Li-ion batteries. These above findings in the current study shed new light on the design of ultrahigh-rate and long-life FeF 3 cathode material for Li-ion batteries.

Polypyrrole-coated α-LiFeO2 nanocomposite with enhanced electrochemical properties for lithium-ion batteries

International Nuclear Information System (INIS)

Zhang, Zhi-jia; Wang, Jia-Zhao; Chou, Shu-Lei; Liu, Hua-Kun; Ozawa, Kiyoshi; Li, Hui-jun

2013-01-01

A conducting α-LiFeO 2 -polypyrrole (α-LiFeO 2 -PPy) nanocomposite material was prepared by the chemical polymerization method as a cathode material for lithium-ion batteries. The porous α-LiFeO 2 was prepared via the microwave hydrothermal method and a post-annealing. The X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy measurements showed that the α-LiFeO 2 nanoparticles were coated with PPy. The polypyrrole coating improves the reversible capacity and cycling stability (104 mAh g −1 at 0.1C after 100 cycles) for lithium-ion batteries. Even at the high rate of 10C, the electrode showed more than 40% of the capacity at low rate (0.1C)

Metal-Organic Frameworks Triggered High-Efficiency Li storage in Fe-Based Polyhedral Nanorods for Lithium-ion Batteries

International Nuclear Information System (INIS)

Shen, Lisha; Song, Huawei; Wang, Chengxin

2017-01-01

Recently, metal organic framework (MOF) nanostructures have been frequently reported in the field of energy storage, specifically for Li-ion or Na-ion storage. By inter-separating the active sites of metal cluster and organic ligands, MOF nanostructures are exceptionally promising for realizing fast ion exchange and high-efficiency transportation and addressing the intricate issues that the energy-intensive Li-ion batteries have faced over many years. The related ion-storage mechanism remains to be explored. Is the traditional redox reaction mechanism operative for these nanostructure, as it is for transitional metal oxide? Herein, taking [Fe_3O(BDC)_3(H_2O)_2(NO_3)]n (Fe-MIL-88B) as an example, an Fe-based metal organic polyhedral nanorods of MIL–88 B structure was designed as an anode for Li-ion storage. When tested at 60 mA g"−"1, the nanoporous Fe-MIL–88 B polyhedral nanorods retained a reversible capacity of 744.5 mAh g"−"1 for more than 400 cycles. Ex situ characterizations of the post-cycled electrodes revealed that both the transition metal ions and the organic ligands contributed to the high reversible specific capacity. The polyhedral nanorods electrodes held the metal-organic skeleton together throughout the battery operation, although in a somewhat different manner than the pristine ones. This further substantiated that some MOF nanostructures are more appropriate than others for stable lithiation/delithiation processes. State-of-the-art CR2032 full cells showed that a high capacity of 86.8 mAh g"−"1 that was retained after 100 cycles (herein, the capacity for the full cell was calculated based on both the weight of the anode and the cathode, and the charge-discharge rate was 0.25C), when commercial LiFePO_4 powders were used as the cathode.

Fabricating Fe3O4/Fe/Biocarbon Fibers using Cellulose Nanocrystals for High-Rate Li-ion Battery Anode

International Nuclear Information System (INIS)

Zhang, Shuzhen; He, Wen; Zhang, Xudong; Yang, Guihua; Ma, Jingyun; Yang, Xuena; Song, Xin

2015-01-01

Highlights: • Mesoporous biocarbon fibers adhered with Fe 3 O 4 /Fe nanoparticles (Fe 3 O 4 /Fe/MBCFs) are synthesized. • This method uses the natural cotton as a template and carbon source. • Fe 3 O 4 /Fe/MBCFs exhibit excellent cycling performance at higher current. - ABSTRACT: Searching the high rate Fe 3 O 4 -based materials for lithium ion batteries (LIBs) is still a great challenge. Here we tackle this problem by developing a facile and green method which uses the natural cotton as a biotemplate and a activity biocarbon source. By this new method, we synthesized the mesoporous biocarbon fibers adhered with Fe 3 O 4 /Fe nanoparticles (Fe 3 O 4 /Fe/MBCFs). Fe 3 O 4 /Fe/MBCFs are a highly stable anode material for high-rate LIBs due to its excellent cycling performance at higher current and fast charging feature. This anode shows a high reversible capacity of 472 mAh g −1 after 500 cycles and can be rapidly charge to 100% in 28.3 min. After 160 cycles at varied current densities from 1 A g −1 to 10 A g −1 , it still delivered a high discharge capacity of 524.6 mAh g −1 and an ultra-high coulombic efficiency close to 100%. This is attributed to the synergistic effects of several factors including the unique mesoporous hybrid construction, the graphitized biocarbon fibers and the chemical bonding between Fe 3 O 4 and Fe nanoparticles. This work is instructive for fabrication and design of nanostructured electrodes with extraordinary properties from biomass renewable resources

LiFePO4 nanoparticles encapsulated in graphene nanoshells for high-performance lithium-ion battery cathodes.

Science.gov (United States)

Fei, Huilong; Peng, Zhiwei; Yang, Yang; Li, Lei; Raji, Abdul-Rahman O; Samuel, Errol L G; Tour, James M

2014-07-11

LiFePO4 encapsulated in graphene nanoshells (LiFePO4@GNS) nanoparticles were synthesized by solid state reaction between graphene-coated Fe nanoparticles and LiH2PO4. The resulting nanocomposite was demonstrated to be a superior lithium-ion battery cathode with improved cycle and rate performances.

Ion bombardment and adsorption studies on ilmenite (FeTiO3) by X-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Schulze, P.D.

1983-01-01

The effects of 5 KeV argon and oxygen ion bombardment on FeTiO3 (ilmenite) at low temperatures have been studied using x-ray photoelectron spectroscopy (XPS). Also, using this same technique, the adsorption of O 2 , NO, N 2 O, and CO at 300 K and the adsorption of O 2 and D 2 O at 150K have been studied. Argon and oxygen ion bombardment of ilmenite have confirmed earlier studies on metal oxides that argon ions generally reduce the anion species while oxygen ions generally oxidize the anion species. The two iron states involved were Fe sup +2 and Fe sup O. The reduction of Ti sup +4 was not verified although a significant shift in the Ti(2p1,3) binding energies toward the metallic state was observed after oxygen ion bombardment at low temperatures. At temperatures above 150K, O 2 adsorbs dissociatively on ilmenite while D 2 O adsorbs molecularly below 170K. Above 300 K NO, N 2 O, and CO do not appear to adsorb dissociatively. Low temperature adsorption of D 2 O was found to be inhibited by predosing the ilmenite with O 2

Ion bombardment and adsorption studies on ilmenite (FeTiO3) by X-ray photoelectron spectroscopy

Science.gov (United States)

Schulze, P. D.

1983-01-01

The effects of 5 KeV argon and oxygen ion bombardment on FeTiO3 (ilmenite) at low temperatures have been studied using X-ray photoelectron spectroscopy (XPS). Also, using this same technique, the adsorption of O2, NO, N2O, and CO at 300 K and the adsorption of O2 and D2O at 150K have been studied. Argon and oxygen ion bombardment of ilmenite have confirmed earlier studies on metal oxides that argon ions generally reduce the anion species while oxygen ions generally oxidize the anion species. The two iron states involved were Fe sup +2 and Fe sup O. The reduction of Ti sup +4 was not verified although a significant shift in the Ti(2p1,3) binding energies toward the metallic state was observed after oxygen ion bombardment at low temperatures. At temperatures above 150K, O2 adsorbs dissociatively on ilmenite while D2O adsorbs molecularly below 170K. Above 300 K No, N2O, and CO do not appear to adsorb dissociatively. Low temperature adsorption of D2O was found to be inhibited by predosing the ilmenite with O2.

Lattice sites, charge states and spin–lattice relaxation of Fe ions in "5"7Mn"+ implanted GaN and AlN

International Nuclear Information System (INIS)

Masenda, H.; Naidoo, D.; Bharuth-Ram, K.; Gunnlaugsson, H.P.; Johnston, K.; Mantovan, R.; Mølholt, T.E.; Ncube, M.; Shayestehaminzadeh, S.; Gíslason, H.P.; Langouche, G.; Ólafsson, S.; Weyer, G.

2016-01-01

The lattice sites, valence states, resulting magnetic behaviour and spin–lattice relaxation of Fe ions in GaN and AlN were investigated by emission Mössbauer spectroscopy following the implantation of radioactive "5"7Mn"+ ions at ISOLDE/CERN. Angle dependent measurements performed at room temperature on the 14.4 keV γ-rays from the "5"7Fe Mössbauer state (populated from the "5"7Mn β"− decay) reveal that the majority of the Fe ions are in the 2+ valence state nearly substituting the Ga and Al cations, and/or associated with vacancy type defects. Emission Mössbauer spectroscopy experiments conducted over a temperature range of 100–800 K show the presence of magnetically split sextets in the “wings” of the spectra for both materials. The temperature dependence of the sextets relates these spectral features to paramagnetic Fe"3"+ with rather slow spin–lattice relaxation rates which follow a T"2 temperature dependence characteristic of a two-phonon Raman process. - Highlights: • The majority of the Fe ions are in the 2+ state, located on near substitutional sites associated with vacancy type defects. • A significant fraction of the Fe ions are in the paramagnetic Fe"3"+ state. • Spin–lattice relaxation of Fe"3"+ in both GaN and AlN follows a two-phonon Raman process.

Velocity dependence of transient hyperfine field at Pt ions rapidly recoiling through magnetized Fe

International Nuclear Information System (INIS)

Stuchbery, A.E.; Ryan, C.G.; Bolotin, H.H.

1981-01-01

The velocity-dependence of the transient hyperfine magnetic field acting at nuclei of 196 Pt ions rapidly recoiling through thin magnetized Fe was investigated at a number of recoil velocities. The state of interest (2 1 + ) was populated by Coulomb excitation using beams of 80- and 120-MeV 32 S and 150- and 220-MeV 58 Ni ions. The 2 1 + →0 1 + γ-ray angular distribution precession measurements were carried out in coincidence with backscattered projectiles. From these results, the strength of the transient field acting on Pt ions recoiling through magnetized Fe with average velocities in the extended range 2.14<=v/vsub(o)<=4.82 (vsub(o) = c/137) was found to be consistent with a linear velocity dependence and to be incompatible with the specific vsup(0.45+-0.18) dependence which has been previously reported to account well for all ions in the mass range from oxygen through samarium. This seemingly singular behaviour for Pt and other ions in the Pt mass vicinity is discussed

On the role of Fe3+ ions in FexOy/C catalysts for hydrogen production from the photodehydrogenation of ethanol

International Nuclear Information System (INIS)

Galindo-Hernández, Félix; Wang, Jin-An; Chen, Lifang; Bokhimi, Xim; Gómez, Ricardo; Pérez-Larios, Alejandro; Nava Entzana, Noel

2013-01-01

Graphical abstract: In Fe x O y /C photocatalyts important effect of Fe 3+ ions in the photodehydrogenation of the ethano was noticed. -- Highlights: • Iron oxides supported on carbon are photoactive catalysts. • Photoactivity in dehydrogenation of ethanol depends of the amount of Fe 3+ ions present in the catalysts. • The capacity of UV–vis absorbance by the Fe x O y /C catalysts is significantly dependent of the amount of Fe 3+ ions. • A maximum of rate constant, K = 2125 μmol h −1 , was obtained from the sample with 30 wt% Fe. -- Abstract: Fe x O y /C photocatalysts at different iron content were prepared by the incipient wet impregnation method and calcined at 773 K. The photocatalysts were characterized by means of nitrogen adsorption–desorption isotherms, surface fractal dimension, non-local density functional theory, X-ray diffraction, Rietveld refinement and UV–vis spectroscopy. The photocatalytic activity was evaluated using the photodehydrogenation of ethanol as a model reaction for the production of hydrogen. The specific surface areas of Fe x O y /C substrates, with 15, 20 and 30 wt% iron content, diminished from 638 to 490 m 2 /g, as the iron content increased. X-ray diffraction analysis showed that iron oxides coexist as wustite and magnetite in samples with Fe contents of 15 and 20 wt%; for sample with 30 wt% Fe, wustite, magnetite and hematite phases were observed. The photophysical, textural and structural properties were modified by the hematite phase formed by thermal treatment. The Rietveld refinements denoted changes in occupancy of Fe 3+ and Fe 2+ in Fe x O y crystallites. A relationship between the Fe 3+ ions content and the reactivity for the hydrogen production from the photodehydrogenation of ethanol (from 1360 to 2125 μmol h −1 ), was evidenced

Lithium-ions diffusion kinetic in LiFePO4/carbon nanoparticles synthesized by microwave plasma chemical vapor deposition for lithium-ion batteries

Science.gov (United States)

Gao, Chao; Zhou, Jian; Liu, Guizhen; Wang, Lin

2018-03-01

Olivine structure LiFePO4/carbon nanoparticles are synthesized successfully using a microwave plasma chemical vapor deposition (MPCVD) method. Microwave is an effective method to synthesize nanomaterials, the LiFePO4/carbon nanoparticles with high crystallinity can shorten diffusion routes for ionic transfer and electron tunneling. Meanwhile, a high quality, complete and homogenous carbon layer with appropriate thickness coating on the surface of LiFePO4 particles during in situ chemical vapor deposition process, which can ensure that electrons are able to transfer fast enough from all sides. Electrochemical impedance spectroscopy (EIS) is carried out to collect information about the kinetic behavior of lithium diffusion in LiFePO4/carbon nanoparticles during the charging and discharging processes. The chemical diffusion coefficients of lithium ions, DLi, are calculated in the range of 10-15-10-9 cm2s-1. Nanoscale LiFePO4/carbon particles show the longer regions of the faster solid-solution diffusion, and corresponding to the narrower region of the slower two-phase diffusion during the insertion/exaction of lithium ions. The CV and galvanostatic charge-discharge measurements show that the LiFePO4/carbon nanoparticles perform an excellent electrochemical performance, especially the high rate capacity and cycle life.

A chemically activated graphene-encapsulated LiFePO4 composite for high-performance lithium ion batteries.

Science.gov (United States)

Ha, Jeonghyun; Park, Seung-Keun; Yu, Seung-Ho; Jin, Aihua; Jang, Byungchul; Bong, Sungyool; Kim, In; Sung, Yung-Eun; Piao, Yuanzhe

2013-09-21

A composite of modified graphene and LiFePO4 has been developed to improve the speed of charging-discharging and the cycling stability of lithium ion batteries using LiFePO4 as a cathode material. Chemically activated graphene (CA-graphene) has been successfully synthesized via activation by KOH. The as-prepared CA-graphene was mixed with LiFePO4 to prepare the composite. Microscopic observation and nitrogen sorption analysis have revealed the surface morphologies of CA-graphene and the CA-graphene/LiFePO4 composite. Electrochemical properties have also been investigated after assembling coin cells with the CA-graphene/LiFePO4 composite as a cathode active material. Interestingly, the CA-graphene/LiFePO4 composite has exhibited better electrochemical properties than the conventional graphene/LiFePO4 composite as well as bare LiFePO4, including exceptional speed of charging-discharging and excellent cycle stability. That is because the CA-graphene in the composite provides abundant porous channels for the diffusion of lithium ions. Moreover, it acts as a conducting network for easy charge transfer and as a divider, preventing the aggregation of LiFePO4 particles. Owing to these properties of CA-graphene, LiFePO4 could demonstrate enhanced and stably long-lasting electrochemical performance.

CEMS and XRD studies on changing shape of iron nano-particles by irradiation of Au ions of Fe-implanted Al2O3 granular layer

International Nuclear Information System (INIS)

Kato, T.; Wakabayashi, H.; Hashimoto, M.; Toriyama, T.; Taniguchi, S.; Hayashi, N.; Sakamoto, I.

2007-01-01

In order to observe an inverse Ostwald ripening of Fe nano-particles in Fe-implanted Al 2 O 3 granular layers, 3 MeV Au ions were irradiated to Fe nano-particles in these layers with doses of 0.5x and 1.5x10 16 ions/cm 2 . It was found by Conversion Electron Mossbauer Spectroscopy (CEMS) that the inverse Ostwald ripening occurred by fractions of percentages and the magnetic anisotropy of Fe nano-particles was induced to the direction of Au ion beam, i.e. perpendicular to the granular plane. The average crystallite diameters of Fe nano-particles for Au ions unirradiated and irradiated samples were measured using Scherrer's formula from FWHM of Fe (110) X-ray Diffraction (XRD) patterns obtained by 2θ and 2θ/θ methods. It was confirmed that the average crystallite diameters of Fe nano-particles in Fe-implanted Al 2 O 3 granular layers were extended by Au ions irradiation. (author)

Polyaniline coated Fe3O4 hollow nanospheres as anode materials for lithium ion batteries

DEFF Research Database (Denmark)

Wang, Xiaoliang; Liu, Yanguo; Han, Hongyan

2017-01-01

Polyaniline (PANI) coated Fe3O4 hollow nanospheres (h-Fe3O4@ PANI) have been successfully synthesized and investigated as anode materials for lithium ion batteries (LIBs). The structure and composition analyses have been performed by employing X-ray diffraction (XRD), scanning electron microscopy...

Investigation of the effect of the incorporated Fe atoms in the ion-beam induced nanopatterns on Si(001)

Energy Technology Data Exchange (ETDEWEB)

Khanbabaee, Behnam; Biermanns, Andreas; Pietsch, Ullrich [Siegen Univ. (Germany). Festkoerperphysik; Cornejo, Marina; Frost, Frank [Leibniz-Institute fuer Oberflaechenmodifizierung e.V. (IOM), Leipzig (Germany)

2012-07-01

Ion beam erosion of semiconductor surfaces can modify the surface and depends on main sputtering parameters; different surface topographies such as ripple or dot like pattern are fabricated on the surface. Recent experiments have shown that the incorporation of foreign metallic atoms during the sputtering process plays a crucial role in pattern formation on surfaces. In the result of investigation we report on the depth profile of Fe atoms incorporated in sputtering process on Si(100) with low energy Kr ion beam. X-ray reflectivity (XRR) measurements determine the concentration profile of Fe atoms. X-ray absorption near edge spectroscopy (XANES) at the Fe K-edge (7112 eV) shows the formation of Fe rich silicide near surface region. X-ray photoelectron spectroscopy (XPS) shows a shift in the binding energy of Si2p levels at the surface compared top bulk confirming the formation of different phases of Fe-silicide on tope and below the surface. The depth profiles obtained by XRR are compared to results obtained by complementary secondary-ion mass spectrometry (SIMS).

Structural and optical properties of α-Fe2O3 nanoparticles, influence by holmium ions

Science.gov (United States)

Mathevula, L. E.; Noto, L. L.; Mothudi, B. M.; Dhlamini, M. S.

2018-04-01

α-Fe2O3 and α-Fe2O3 doped with different concentration of holmium ions were synthesized by a simple sol-gel method. The XRD data confirmed the hexagonal structure of α-Fe2O3 for un-doped and holmium doped samples. The crystallite size was found to be decreasing with increasing holmium concentration. The amount of holmium was quantified using an EDS, which shows an increase in holmium quantity as concentration increases. The UV-Vis measurement shows an absorption edge around 570 nm. The band gap was estimated using the Kubelka-Munk relation and it was found to be fluctuating between 1.94 eV and 2.04 eV. The PL spectra confirmed the effect of holmium ions on luminescence properties of α-Fe2O3 which showed a maximum intensity at 0.1 mol% Holmium, and quenching as the concentration is increased from 0.3 mol% to 0.9 mol%.

Carbon nanotube-wrapped Fe2O3 anode with improved performance for lithium-ion batteries

Directory of Open Access Journals (Sweden)

Guoliang Gao

2017-03-01

Full Text Available Metall oxides have been proven to be potential candidates for the anode material of lithium-ion batteries (LIBs because they offer high theoretical capacities, and are environmentally friendly and widely available. However, the low electronic conductivity and severe irreversible lithium storage have hindered a practical application. Herein, we employed ethanolamine as precursor to prepare Fe2O3/COOH-MWCNT composites through a simple hydrothermal synthesis. When these composites were used as electrode material in lithium-ion batteries, a reversible capacity of 711.2 mAh·g−1 at a current density of 500 mA·g−1 after 400 cycles was obtained. The result indicated that Fe2O3/COOH-MWCNT composite is a potential anode material for lithium-ion batteries.

Structural-phase changes of α-Fe implanted with high ion doses

International Nuclear Information System (INIS)

Ivanov, Y.F.; Pogrebnyak, A.; Martynenko, V.

2001-01-01

The CEMS method was used to examine and implanted layer of α-Fe with a thickness of up to 100 nm. The radiation of α-Fe with carbon ions results of the formation of the solid solution of carbon in α-Fe and the precipitation of the iron carbides Fe 2 C. The implantation of aluminium in the α-Fe is accompanied by the formation of the order phase Fe 3 Al. The results of show that the phase the composition of the surface layer of α-Fe, irradiated with titanium, is represented by the solid solution of the titanium in α-Fe, and also by the micro-clusters of iron characterised by different environment of the titanium atoms of the level of several co-ordination spheres. The presence of these micro-clusters indicates the non-uniform distribution of titanium in α-Fe. The additional Auger analysis of the specimens of α-Fe, implanted with titanium with a dose of 5 x 10 -17 cm -2 , showed a high concentration of carbon (up to 20 at.%) in the layer up to 50 nm thick. The authors of 2 assumed that the carbon, implanted from the residual atmosphere, affects not only the resultant profile of the distribution of titanium in the depth of α-Fe, but also the change of the physical-mechanical properties of the surface layer. The main aim of the investigations was to examine the phase composition and the formation of secondary defects (dislocations and dislocation sub structures) in the surface layer of α-Fe, implanted with titanium, aluminium, carbon, with a dose of 5 x 10 -17 cm -2

Effect of 120 MeV 28Si9+ ion irradiation on structural and magnetic properties of NiFe2O4 and Ni0.5Zn0.5Fe2O4

Science.gov (United States)

Sharma, R.; Raghuvanshi, S.; Satalkar, M.; Kane, S. N.; Tatarchuk, T. R.; Mazaleyrat, F.

2018-05-01

NiFe2O4, Ni0.5Zn0.5Fe2O4 samples were synthesized using sol-gel auto combustion method, and irradiated by using 120 MeV 28Si9+ ion with ion fluence of 1×1012 ions/cm2. Characterization of pristine, irradiated samples were done using X-Ray Diffraction (XRD), Field Emission Scanning Microscopy (FE-SEM), Energy Dispersive X-ray Analysis (EDAX) and Vibrating Sample Magnetometer (VSM). XRD validates the single phase nature of pristine, irradiated Ni- Zn nano ferrite except for Ni ferrite (pristine, irradiated) where secondary phases of α-Fe2O3 and Ni is observed. FE- SEM images of pristine Ni, Ni-Zn ferrite show inhomogeneous nano-range particle size distribution. Presence of diamagnetic ion (Zn2+) in NiFe2O4 increases oxygen positional parameter (u 4¯3m ), experimental, theoretical saturation magnetization (Msexp., Msth.), while decreases the grain size (Ds) and coercivity (Hc). With irradiation Msexp., Msth. increases but not much change are observed in Hc. New antistructure modeling for the pristine, irradiated Ni and Ni-Zn ferrite samples was used for describing the surface active centers.

High-Capacity and Long-Cycle Life Aqueous Rechargeable Lithium-Ion Battery with the FePO4 Anode.

Science.gov (United States)

Wang, Yuesheng; Yang, Shi-Ze; You, Ya; Feng, Zimin; Zhu, Wen; Gariépy, Vincent; Xia, Jiexiang; Commarieu, Basile; Darwiche, Ali; Guerfi, Abdelbast; Zaghib, Karim

2018-02-28

Aqueous lithium-ion batteries are emerging as strong candidates for a great variety of energy storage applications because of their low cost, high-rate capability, and high safety. Exciting progress has been made in the search for anode materials with high capacity, low toxicity, and high conductivity; yet, most of the anode materials, because of their low equilibrium voltages, facilitate hydrogen evolution. Here, we show the application of olivine FePO 4 and amorphous FePO 4 ·2H 2 O as anode materials for aqueous lithium-ion batteries. Their capacities reached 163 and 82 mA h/g at a current rate of 0.2 C, respectively. The full cell with an amorphous FePO 4 ·2H 2 O anode maintained 92% capacity after 500 cycles at a current rate of 0.2 C. The acidic aqueous electrolyte in the full cells prevented cathodic oxygen evolution, while the higher equilibrium voltage of FePO 4 avoided hydrogen evolution as well, making them highly stable. A combination of in situ X-ray diffraction analyses and computational studies revealed that olivine FePO 4 still has the biphase reaction in the aqueous electrolyte and that the intercalation pathways in FePO 4 ·2H 2 O form a 2-D mesh. The low cost, high safety, and outstanding electrochemical performance make the full cells with olivine or amorphous hydrated FePO 4 anodes commercially viable configurations for aqueous lithium-ion batteries.

Distribution of the ligand field at the Fe2+ ion in frozen aqueous solutions of Fe(ClO4)2

International Nuclear Information System (INIS)

Nagy, D.L.; Horvath, D.; Szuecs, I.S.; Spiering, H.

1981-01-01

Moessbauer spectra of eutectic frozen aqueous solutions of Fe(ClO 4 ) 2 have been measured at 4.2 K in applied longitudinal magnetic fields up to 5 T. The spectra are interpreted in terms of a model accounting for the random distribution of the ligand field at the Fe 2+ ion owing to the amorphity of the environment. The equilibrium state of the Fe(H 2 O) 6 2+ complex is determined by a static Jahn-Teller calculation. The main features of all spectra can be well reproduced by choosing Esub(JT)(tau)=140 cm -1 and ωsub(tau)=150 cm -1 . (author)

Lattice sites, charge states and spin–lattice relaxation of Fe ions in {sup 57}Mn{sup +} implanted GaN and AlN

Energy Technology Data Exchange (ETDEWEB)

Masenda, H., E-mail: hilary.masenda@wits.ac.za [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Naidoo, D. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Bharuth-Ram, K. [Physics Department, Durban University of Technology, Durban 4000 (South Africa); iThemba LABS, PO Box 725, Somerset West 7129 (South Africa); Gunnlaugsson, H.P. [PH Department, ISOLDE/CERN, 1211 Geneva 23 (Switzerland); KU Leuven, Instituut voor Kern-en Stralingsfysica, 3001 Leuven (Belgium); Johnston, K. [PH Department, ISOLDE/CERN, 1211 Geneva 23 (Switzerland); Mantovan, R. [Laboratorio MDM, IMM-CNR, Via Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Mølholt, T.E. [PH Department, ISOLDE/CERN, 1211 Geneva 23 (Switzerland); Ncube, M. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Shayestehaminzadeh, S. [Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 5274 Aachen (Germany); Gíslason, H.P. [Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavík (Iceland); Langouche, G. [KU Leuven, Instituut voor Kern-en Stralingsfysica, 3001 Leuven (Belgium); Ólafsson, S. [Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavík (Iceland); Weyer, G. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus (Denmark)

2016-03-01

The lattice sites, valence states, resulting magnetic behaviour and spin–lattice relaxation of Fe ions in GaN and AlN were investigated by emission Mössbauer spectroscopy following the implantation of radioactive {sup 57}Mn{sup +} ions at ISOLDE/CERN. Angle dependent measurements performed at room temperature on the 14.4 keV γ-rays from the {sup 57}Fe Mössbauer state (populated from the {sup 57}Mn β{sup −} decay) reveal that the majority of the Fe ions are in the 2+ valence state nearly substituting the Ga and Al cations, and/or associated with vacancy type defects. Emission Mössbauer spectroscopy experiments conducted over a temperature range of 100–800 K show the presence of magnetically split sextets in the “wings” of the spectra for both materials. The temperature dependence of the sextets relates these spectral features to paramagnetic Fe{sup 3+} with rather slow spin–lattice relaxation rates which follow a T{sup 2} temperature dependence characteristic of a two-phonon Raman process. - Highlights: • The majority of the Fe ions are in the 2+ state, located on near substitutional sites associated with vacancy type defects. • A significant fraction of the Fe ions are in the paramagnetic Fe{sup 3+} state. • Spin–lattice relaxation of Fe{sup 3+} in both GaN and AlN follows a two-phonon Raman process.

Microstructure and mechanical properties of ion-beam-produced Fe-Ti-(N), Fe-Ti-(C), and Fe-Ti-(C,N) surface films

Science.gov (United States)

Hirvonen, J.-P.; Nastasi, M.; Zocco, T. G.; Jervis, T. R.

1990-06-01

Ion-mixed films of Fe53 Ti47 were produced by ion irradiating a Fe-Ti multilayer structure on AISI 304 stainless steel. The ion-mixed films were subsequently implanted with nitrogen, carbon, or both carbon and nitrogen. The microstructure following nitrogen implantation consisted of a bcc solid solution of iron and titanium and finely dispersed TiN precipitates. In the cases of carbon or carbon and nitrogen implantation, a two-phase structure consisting of an amorphous matrix with TiC or Ti(C,N) precipitates was found. All these films initially possessed improved tribological properties as revealed by lowered friction and increased wear resistance. However, after an extended test of 1000 wear cycles, a reduced friction was only observed for the carbon or carbon and nitrogen implanted samples. The wear track on the dual implanted surface was extremely smooth, while the surface of the nitrogen-implanted sample was partly worn through, causing the friction to increase to the level of the untreated sample. The improved tribological properties of the implanted films are attributed to an increase in surface hardness. However, the surface hardness is unable to explain differences between different implantations. In the case of the dual carbon and nitrogen implantation, improvements appear to be in part the result from an increased capability to accommodate plastic deformation. These conclusions are supported by transmission electron microscope studies of the wear tracks as well as by nanoindentation measurements.

Advanced carbon materials/olivine LiFePO4 composites cathode for lithium ion batteries

Science.gov (United States)

Gong, Chunli; Xue, Zhigang; Wen, Sheng; Ye, Yunsheng; Xie, Xiaolin

2016-06-01

In the past two decades, LiFePO4 has undoubtly become a competitive candidate for the cathode material of the next-generation LIBs due to its abundant resources, low toxicity and excellent thermal stability, etc. However, the poor electronic conductivity as well as low lithium ion diffusion rate are the two major drawbacks for the commercial applications of LiFePO4 especially in the power energy field. The introduction of highly graphitized advanced carbon materials, which also possess high electronic conductivity, superior specific surface area and excellent structural stability, into LiFePO4 offers a better way to resolve the issue of limited rate performance caused by the two obstacles when compared with traditional carbon materials. In this review, we focus on advanced carbon materials such as one-dimensional (1D) carbon (carbon nanotubes and carbon fibers), two-dimensional (2D) carbon (graphene, graphene oxide and reduced graphene oxide) and three-dimensional (3D) carbon (carbon nanotubes array and 3D graphene skeleton), modified LiFePO4 for high power lithium ion batteries. The preparation strategies, structure, and electrochemical performance of advanced carbon/LiFePO4 composite are summarized and discussed in detail. The problems encountered in its application and the future development of this composite are also discussed.

Critical current enhancement driven by suppression of superconducting fluctuation in ion-gated ultrathin FeSe

Science.gov (United States)

Harada, T.; Shiogai, J.; Miyakawa, T.; Nojima, T.; Tsukazaki, A.

2018-05-01

The framework of phase transition, such as superconducting transition, occasionally depends on the dimensionality of materials. Superconductivity is often weakened in the experimental conditions of two-dimensional thin films due to the fragile superconducting state against defects and interfacial effects. In contrast to this general trend, superconductivity in the thin limit of FeSe exhibits an opposite trend, such as an increase in critical temperature (T c) and the superconducting gap exceeding the bulk values; however, the dominant mechanism is still under debate. Here, we measured thickness-dependent electrical transport properties of the ion-gated FeSe thin films to evaluate the superconducting critical current (I c) in the ultrathin FeSe. Upon systematically decreasing the FeSe thickness by the electrochemical etching technique in the Hall bar-shaped electric double-layer transistors, we observed a dramatic enhancement of I c reaching about 10 mA and corresponding to about 107 A cm‑2 in the thinnest condition. By analyzing the transition behavior, we clarify that the suppressed superconducting fluctuation is one of the origins of the large I c in the ion-gated ultrathin FeSe films. These results indicate the existence of a robust superconducting state possibly with dense Cooper pairs at the thin limit of FeSe.

Electrochemical performance of Fe3O4 micro flower as anode for lithium ion batteries

Science.gov (United States)

Noerochim, Lukman; Anggara, Dika; Susanti, Diah; Subhan, Achmad; Sudaryanto

2018-04-01

Graphite is generally employed in commercial lithium ion batteries which has a specific capacity of 372 mAh/g. In this study, graphite is replaced with carbon-coated magnetite (Fe3O4/C) which has large theoretical specific capacity of 926 mAh/g, environmental friendly, and low cost production. The synthesis of Fe3O4/C is carried out by hydrothermal method with reacting FeCl3 and hexamethylenetetramine (HMT) at temperature variation of 160, 170 and 180°C. The following process is heated by calcination at temperature variations 450, 500 and 550°C. XRD and SEM results show that the as-prepared Fe3O4/C powder has a single phase of Fe3O4 and morphology micro-flowers like with size between 700 nm - 3 µm. CV test results show redox reaction occurs in the voltage range between 0.21-0.85 V and 1.68-1.81 V. The highest specific discharge capacity is obtained 644 mAh/g for specimen with temperature hydrothermal of 170°C and temperature calcination of 550°C. This result shows that Fe3O4/C has a high potential as anode material for lithium ion battery.

One Step Hydrothermal Synthesis of FeCO3 Cubes for High Performance Lithium-ion Battery Anodes

International Nuclear Information System (INIS)

Zhang, Congcong; Liu, Weijian; Chen, Dongyang; Huang, Jiayi; Yu, Xiaoyuan; Huang, Xueyan; Fang, Yueping

2015-01-01

Highlights: • FeCO 3 nanocubes with edge length of ∼300 nm were prepared. • A reversible capacity of 761 mAh g −1 was achieved at 200 mA g −1 after 130 cycles. • Cyclic voltammetry and electrochemical impedance were employed to understand the cell performances. - Abstract: Uniform FeCO 3 cubes with edge length of ∼300 nm were prepared by a facile one-step hydrothermal reaction and studied as anode material for lithium-ion batteries. Interestingly, the FeCO 3 anode has an extremely high initial specific capacity of 1796 mAh g −1 . After cycling at a current rate of 200 mA g −1 for 130 cycles, an excellent discharge capacity of 761 mAh g −1 is still maintained. Moreover, the FeCO 3 anode exhibits significant high-rate capability, e.g., ∼430 mAh g −1 is obtained at a current rate of 1200 mA g −1 . The observation of the FeCO 3 cubes represents an important development of realizing both high capacity and good cycleability in conversion type anode materials for lithium-ion battery at the same time. Such cheap, easy-to-make, and environmentally benign material is promising for practical deployment for lithium ion batteries anode.

TEM characterization of simultaneous triple ion implanted ODS Fe12Cr

International Nuclear Information System (INIS)

Castro, Vanessa de; Briceno, Martha; Lozano-Perez, Sergio; Trocellier, Patrick; Roberts, Steve G.; Pareja, Ramiro

2014-01-01

Understanding the behavior of oxide dispersion strengthened (ODS) ferritic/martensitic steels under irradiation is vital in the design of advanced fusion reactors. In this work, a simultaneous triple ion implanted ODS Fe12Cr steel was investigated by transmission electron microscopy in order to determine the effect of irradiation on the grain and dislocation structures, oxide nanoparticles and other secondary phases present in the steel. The ODS steel was irradiated at RT with Fe 8+ , He + and H + at the JANNUS-Saclay facility to a damage of 4.4 dpa. Results show that ODS nanoparticles appear very stable under these irradiation conditions

LiFePO4/C nanocomposites for lithium-ion batteries

Science.gov (United States)

Eftekhari, Ali

2017-03-01

LiFePO4, as the most famous member of the family of olivine-type lithium transition metal phosphates, is one of the promising candidates for the cathodes of lithium-ion batteries. However, its battery performance is limited by its low electrical conductivity and slow Li solid-state diffusion. Various methods have been attempted to improve the battery performance of lithium iron phosphate. Among them, compositing the LiFePO4 with carbon nanomaterials seems to be the most promising, as it is facile and efficient. Carbon nanomaterials usually serve as a conductive agent to improve the electrical conductivity while increasing the material porosity in which the solid-state diffusion distances are significantly shortened. Owing to the popularity of various carbonaceous nanomaterials, there is no straightforward line of research for comparing the LiFePO4/C nanocomposites. This review aims to provide a general perspective based on the research achievements reported in the literature. While surveying the research findings reported in the literature, controversial issues are also discussed. The possible contribution of pseudocapacitance as a result of functionalized carbon or LiFePO4 lattice defects is described, since from a practical perspective, a LiFePO4/C electrode can be considered as a supercapacitor at high C rates (with a specific capacitance as large as 200 F g-1). The Li diffusion in LiFePO4 has not been well understood yet; while the Li diffusion within the LiFePO4 lattice seems to be quite fast, the peculiar interfacial electrochemistry of LiFePO4 slows down the diffusion within the entire electrode by a few orders of magnitude.

Comparative transcriptome analysis of rice seedlings induced by different doses of heavy ion radiation

Science.gov (United States)

Zhao, Qian; Sun, Yeqing; Wang, Wei

2016-07-01

Highly ionizing radiation (HZE) in space is considered as a main factor causing biological effects on plant seeds. To investigate the different effects on genome-wide gene expression of low-dose and high-dose ion radiation, we carried out ground-base carbon particle HZE experiments with different cumulative doses (0Gy, 0.2Gy, 2Gy) to rice seeds and then performed comparative transcriptome analysis of the rice seedlings. We identified a total of 2551 and 1464 differentially expressed genes (DEGs) in low-dose and high-dose radiation groups, respectively. Gene ontology analyses indicated that low-dose and high-dose ion radiation both led to multiple physiological and biochemical activities changes in rice. By Gene Ontology analyses, the results showed that only one process-oxidation reduction process was enriched in the biological process category after high-dose ion radiation, while more processes such as response to biotic stimulus, heme binding, tetrapyrrole binding, oxidoreductase activity, catalytic activity and oxidoreductase activity were significantly enriched after low-dose ion radiation. The results indicated that the rice plants only focused on the process of oxidation reduction to response to high-dose ion radiation, whereas it was a coordination of multiple biological processes to response to low-dose ion radiation. To elucidate the transcriptional regulation of radiation stress-responsive genes, we identified several DEGs-encoding TFs. AP2/EREBP, bHLH, C2H2, MYB and WRKY TF families were altered significantly in response to ion radiation. Mapman analysis speculated that the biological effects on rice seedlings caused by the radiation stress might share similar mechanisms with the biotic stress. Our findings highlight important alterations in the expression of radiation response genes, metabolic pathways, and TF-encoding genes in rice seedlings exposed to low-dose and high-dose ion radiation.

Calculation of the substitutional fraction of ion-implanted He in an Fe target

OpenAIRE

Erhart, Paul; Marian, Jaime

2010-01-01

Ion-implantation is a useful technique to study irradiation damage in nuclear materials. To study He effects in nuclear fusion conditions, He is co-implanted with damage ions to reproduce the correct He/dpa ratios in the desired or available depth range. However, the short-term fate of these He ions, i.e over the time scales of their own collisional phase, has not been yet unequivocally established. Here we present an atomistic study of the short-term evolution of He implantation in an Fe sub...

Lowering of the L10 ordering temperature of FePt nanoparticles by He+ ion irradiation

International Nuclear Information System (INIS)

Wiedwald, U.; Klimmer, A.; Kern, B.; Han, L.; Boyen, H.-G.; Ziemann, P.; Fauth, K.

2007-01-01

Arrays of FePt particles (diameter 7 nm) with mean interparticle distances of 60 nm are prepared by a micellar technique on Si substrates. The phase transition of these magnetic particles towards the chemically ordered L1 0 phase is tracked for 350 kV He + ion irradiated samples and compared to a nonirradiated reference. Due to the large separation of the magnetically decoupled particles the array can be safely annealed without any agglomeration as usually observed for more densely packed colloidal FePt nanoparticles. The He + ion exposure yields a significant reduction of the ordering temperature by more than 100 K

Three-dimensional graphene/LiFePO4 nanostructures as cathode materials for flexible lithium-ion batteries

International Nuclear Information System (INIS)

Ding, Y.H.; Ren, H.M.; Huang, Y.Y.; Chang, F.H.; Zhang, P.

2013-01-01

Graphical abstract: Graphene/LiFePO 4 composites as a high-performance cathode material for flexible lithium-ion batteries have been prepared by using a co-precipitation method to synthesize graphene/LiFePO4 powders as precursors and then followed by a solvent evaporation process. - Highlights: • Flexible LiFePO 4 /graphene films were prepared first time by a solvent evaporation process. • The flexible electrode exhibited a high discharge capacity without conductive additives. • Graphene network offers the electrode adequate strength to withstand repeated flexing. - Abstract: Three-dimensional graphene/LiFePO 4 nanostructures for flexible lithium-ion batteries were successfully prepared by solvent evaporation method. Structural characteristics of flexible electrodes were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrochemical performance of graphene/LiFePO 4 was examined by a variety of electrochemical testing techniques. The graphene/LiFePO 4 nanostructures showed high electrochemical properties and significant flexibility. The composites with low graphene content exhibited a high capacity of 163.7 mAh g −1 at 0.1 C and 114 mAh g −1 at 5 C without further incorporation of conductive agents

Eu(III)-functionalized MIL-124 as fluorescent probe for highly selectively sensing ions and organic small molecules especially for Fe(III) and Fe(II).

Science.gov (United States)

Xu, Xiao-Yu; Yan, Bing

2015-01-14

A layerlike MOF (MIL-124, orGa2(OH)4(C9O6H4)) has been prepared and chosen as a parent compound to encapsulate Eu(3+) cations by one uncoordinated carbonyl group in its pores. The Eu(3+)-incorporated sample (Eu(3+)@MIL-124) is fully characterized, which shows excellent luminescence and good fluorescence stability in water or other organic solvents. Subsequently, we choose Eu(3+)@MIL-124 as sensitive probe for sensing metal ions, anions, and organic small molecules because of its robust framework. Studying of the luminescence properties reveals that the complex Eu(3+)@MIL-124 was developed as a highly selective and sensitive probe for detection of Fe(3+) (detection limit, 0.28 μM) and Fe(2+) ions through fluorescence quenching of Eu(3+) and MOF over other metal ions. In connection to this, a probable sensing mechanism was also discussed in this paper. In addition, when Eu(3+)@MIL-124 was immersed in the different anions solutions and organic solvents, it also shows highly selective for Cr2O7(2-)(detection limit, 0.15 μM)and acetone. Remarkably, it is the first Eu-doped MOF to exhibit an excellent ability for the detection of Fe(3+) and Fe(2+) in an aqueous environment without any structural disintegration of the framework.

First-principles investigation of the electronic and Li-ion diffusion properties of LiFePO4 by sulfur surface modification

International Nuclear Information System (INIS)

Xu, Guigui; Zhong, Kehua; Zhang, Jian-Min; Huang, Zhigao

2014-01-01

We present a first-principles calculation for the electronic and Li-ion diffusion properties of the LiFePO 4 (010) surface modified by sulfur. The calculated formation energy indicates that the sulfur adsorption on the (010) surface of the LiFePO 4 is energetically favored. Sulfur is found to form Fe-S bond with iron. A much narrower band gap (0.67 eV) of the sulfur surface-modified LiFePO 4 [S-LiFePO 4 (010)] is obtained, indicating the better electronic conductive properties. By the nudged elastic band method, our calculations show that the activation energy of Li ions diffusion along the one-dimensional channel on the surface can be effectively reduced by sulfur surface modification. In addition, the surface diffusion coefficient of S-LiFePO 4 (010) is estimated to be about 10 −11 (cm 2 /s) at room temperature, which implies that sulfur modification will give rise to a higher Li ion carrier mobility and enhanced electrochemical performance

Quality monitoring methods of initial and terminal manufacture of LiFePO4 based lithium ion batteries by capillary electrophoresis.

Science.gov (United States)

Xie, Xia; Yang, Yang; Zhou, Henghui; Li, Meixian; Zhu, Zhiwei

2018-03-01

Magnetic impurities of lithium ion battery degrade both the capacity and cycling rates, even jeopardize the safety of the battery. During the material manufacture of LiFePO 4 , two opposite and extreme cases (trace impurity Fe(II) with high content of Fe(III) background in FePO 4 of initial end and trace Fe(III) with high content of Fe(II) background in LiFePO 4 of terminal end) can result in the generation of magnetic impurities. Accurate determination of impurities and precise evaluation of raw material or product are necessary to ensure reliability, efficiency and economy in lithium ion battery manufacture. Herein, two kinds of rapid, simple, and sensitive capillary electrophoresis (CE) methods are proposed for quality monitoring of initial and terminal manufacture of LiFePO 4 based lithium ion batteries. The key to success includes the smart use of three common agents 1,10-phenanthroline (phen), EDTA and cetyltrimethyl ammonium bromide (CTAB) in sample solution or background electrolyte (BGE), as well as sample stacking technique of CE feature. Owing to the combination of field-enhanced sample injection (FESI) technique with high stacking efficiency, detection limits of 2.5nM for Fe(II) and 0.1μM for Fe(III) were obtained corresponding to high content of Fe(III) and Fe(II), respectively. The good recoveries and reliability demonstrate that the developed methods are accurate approaches for quality monitoring of LiFePO 4 manufacture. Copyright © 2017 Elsevier B.V. All rights reserved.

The parameters of the free ions Mn5+ and Fe6+

International Nuclear Information System (INIS)

Andreici, E L; Gruia, A S; Avram, N M

2012-01-01

The analysis of the behavior of iron-group ions in crystals, using a free-ion Hamiltonian that involves terms with only three parameters (B, C and ξ), seems to be erroneous since it is incapable of correctly predicting the levels of even a free ion. Such calculations may lead to erroneous conclusions concerning the crystal-field effects and the electron-phonon interaction. In this paper, we present the results of the most exact calculation of the parameters for free ions and the energy levels of Mn 5+ and Fe 6+ with 3d 2 configuration. In the single-configuration approximation, the effective Hamiltonian of the free ions takes into account not only the electrostatic and the spin-orbit interactions, but also the relativistic ones (spin-spin, orbit-orbit and spin-other-orbit) and the linear correlation effect. For both free ions we have calculated the semi-empirical parameters included in the interaction Hamiltonian and the energy level scheme. The values of these parameters are obtained by fitting experimental data with the minimum value of rms errors. The final results are discussed.

Impact of He and Cr on defect accumulation in ion-irradiated ultrahigh-purity Fe(Cr) alloys

DEFF Research Database (Denmark)

Prokhodtseva, A.; Décamps, B.; Ramar, Amuthan

2013-01-01

The effect of He on the primary damage induced by irradiation in ultrahigh-purity (UHP) Fe and Fe(Cr) alloys was investigated by transmission electron microscopy (TEM). Materials were irradiated at room temperature in situ by TEM in a microscope coupled to two ion accelerators, simultaneously pro...

Atom-probe field-ion-microscopy study of Fe-Ti alloys

International Nuclear Information System (INIS)

Pickering, H.W.; Kuk, Y.; Sakurai, T.

1980-01-01

A newly developed high-performance atom-probe (field ion microscope) was employed for the composition analysis of Fe-Ti alloys and their interactions with ambient gas, such as H 2 and O 2 . With a mass resolution (m/Δm) better than 2000 and a spatial resolution of a few A, all isotopes of Fe and Ti and their hydrides and other compounds are clearly resolved during the depth profile study. Some of our findings are: (1) Titanium segregated on the surface and grain boundaries upon heating (greater than or equal to 900 0 C), in the form of oxides, and (2) some Ti in the bulk forms clusters of various sizes with C, O, and/or N as nuclei

TEM characterization of simultaneous triple ion implanted ODS Fe12Cr

Energy Technology Data Exchange (ETDEWEB)

Castro, Vanessa de, E-mail: vanessa.decastro@uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid (Spain); Briceno, Martha [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Johnson Matthey Technology Centre, Blount’s Court Rd, Sonning Common RG4 9NH (United Kingdom); Lozano-Perez, Sergio [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Trocellier, Patrick [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Roberts, Steve G. [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Pareja, Ramiro [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid (Spain)

2014-12-15

Understanding the behavior of oxide dispersion strengthened (ODS) ferritic/martensitic steels under irradiation is vital in the design of advanced fusion reactors. In this work, a simultaneous triple ion implanted ODS Fe12Cr steel was investigated by transmission electron microscopy in order to determine the effect of irradiation on the grain and dislocation structures, oxide nanoparticles and other secondary phases present in the steel. The ODS steel was irradiated at RT with Fe{sup 8+}, He{sup +} and H{sup +} at the JANNUS-Saclay facility to a damage of 4.4 dpa. Results show that ODS nanoparticles appear very stable under these irradiation conditions.

Probing the failure mechanism of nanoscale LiFePO4 for Li-ion batteries

International Nuclear Information System (INIS)

Gu, Meng; Yan, Pengfei; Wang, Chongmin; Shi, Wei; Zheng, Jianming; Zhang, Ji-guang

2015-01-01

LiFePO 4 is a high power rate cathode material for lithium ion battery and shows remarkable capacity retention, featuring a 91% capacity retention after 3300 cycles. In this work, we use high-resolution transmission electron microscopy and electron energy loss spectroscopy to study the gradual capacity fading mechanism of LiFePO 4 materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO 4 cathode shows surface amorphization and loss of oxygen species, which directly contribute to the gradual capacity fading of the battery. The finding can guide the design and improvement of LiFePO 4 cathode for high-energy and high-power rechargeable battery for electric transportation

Pilot Study on Long Term Effects of HZE Exposure on the Canine Brain

Science.gov (United States)

Budinger, T.; Brennan, K.; Pearlstein, R.

A ground-based pilot experiment was initiated in December 1992 to evaluate the long term effects on health and aging after HZE cosmic radiation of the canine brain. Six adult male beagle dogs (1 yr) from the UC Davis breeding colony at the Laboratory for Energy Related Health Research were researched in this study. Iron nuclei at 600 MeV/amu (180 keV/mm) were used to irradiate the whole brain. The fluence of 3 x 106 iron nuclei/ cm2 mimics the HZE exposure (all > He) for a 2- year mission to Mars. The HZE irradiation was a fully stripped iron particle beam at the LBNL BEVALAC. Using a Raster Scanner we were able to spread the beam to deliver a uniform dose over the brain. The total dose to the brain was 200 cGy. Four dogs were whole brain irradiated with iron and two dogs served as litter-mate controls. The control dogs received a similar amount of background neutron irradiation as the irradiated dogs. One of the control dogs died suddenly 3/98 of intestinal cancer unrelated to the brain irradiation. That brain was not harvested before autolysis had prevented analysis. Periodic PET metabolism and yearly MRI studies have been done on these dog's brain since irradiation. All dogs had yearly physical, neurological and blood chemistry work-ups. PET imaging was performed with the Donner 600-crystal high-resolution PET (2.6 mm resolution) and with the commercial PET, CTI/Siemens ECAT 951 PET Scanner (5 mm resolution). NMR imaging is performed with the 1 5T GE Signa at UCSF using T spoiled gradient imaging.1 sequences for T1 contrast at 1 mm resolution as well as a T2 weighted spin echo imaging sequence at 1 mm resolution. A major goal of this work is to present an accurate method for measuring surface areas and volumes of the irradiated vs the non-irradiated canine brain using MRI data which are isotropic in resolution at the 1 mm level. This allows us to monitor the changes in brain size with aging and radiation exposure. Nine years post irradiation, these dog brains

Valency stabilization of polyvalent ions during gamma irradiation of their aqueous solutions by sacrificial protection. I- Valency stabilization of Fe (II) ions by sulphate ions

Energy Technology Data Exchange (ETDEWEB)

Barakat, M F [Nuclear chemistry department, hot lab. center, Atomic Energy Authority, Cairo, (Egypt); Abdel-Hamid, M M [Arab Atomic Energy Agency, P.O. Box 402 El-Manzah-1004 Tunis, (Tunisia)

1995-10-01

Polyvalent ions are very sensitive to gamma irradiation in aqueous solutions. The present work is a part of a more comprehensive study dealing with the stabilization or protection of certain oxidation states of some polyvalent ions during their gamma irradiation in aqueous systems. The behaviour of aqueous acidic Fe (II) solutions during gamma irradiation, in presence the prevailing protection mechanism. The conditions and stabilization limits in the studied case has been found out. 9 figs.

Valency stabilization of polyvalent ions during gamma irradiation of their aqueous solutions by sacrificial protection. I- Valency stabilization of Fe (II) ions by sulphate ions

International Nuclear Information System (INIS)

Barakat, M.F.; Abdel-Hamid, M.M.

1995-01-01

Polyvalent ions are very sensitive to gamma irradiation in aqueous solutions. The present work is a part of a more comprehensive study dealing with the stabilization or protection of certain oxidation states of some polyvalent ions during their gamma irradiation in aqueous systems. The behaviour of aqueous acidic Fe (II) solutions during gamma irradiation, in presence the prevailing protection mechanism. The conditions and stabilization limits in the studied case has been found out. 9 figs

SRAP analysis of M3 lotus mutants induced by Fe+ ion implantation

International Nuclear Information System (INIS)

Jia Yanyan; Deng Chuanliang; Gao Jun; Ren Yingxue; Wang Ningna; Gao Wujun; Lu Longdou; Zhang Tao; Li Pengfei

2011-01-01

To examine and determine the lotus mutants induced by the same Fe + ion implantation at the molecular level, the SRAP technique was used, and the non denatured polyacrylamide gel electrophoresis was undertaken to analyze the PCR products. At the optimized SRAP reaction condition, of the 121 primer pairs tested, 10 primer pairs could amplify stable and remarkable specific bands, with primer polymorphism of 8.26%. This 10 primer pairs amplified a total of 215 bands, 83 of which were polymorphic, and the percent of polymorphic bands was 38.6%. A total of 141 bands were amplified for the mutant 1, 22 of which were different from the control with the variation ratio of 15.6%. However, the variation ratios of mutant 2 to 6 were 16.4%, 17.1%, 16.9%, 18.2% and 20.5% respectively. The results indicated that Fe + ion implantation into the seeds of Baiyangdian red lotus could induce random genetic DNA variations. (authors)

In-situ XMCD evaluation of ferromagnetic state at FeRh thin film surface induced by 1 keV Ar ion beam irradiation and annealing

Energy Technology Data Exchange (ETDEWEB)

Matsui, T. [Research Organization for the 21st Century, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Aikoh, K. [Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Sakamaki, M.; Amemiya, K. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Iwase, A. [Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan)

2015-12-15

Surface ferromagnetic state of FeRh thin films irradiated with 1 keV Ar ion-beam has been investigated by using soft X-ray Magnetic Circular Dichroism (XMCD). It was revealed that the Fe atoms of the samples were strongly spin-polarized after Ar ion-beam irradiation. Due to its small penetration depth, 1 keV Ar ion-beam irradiation can modify the magnetic state at subsurface of the samples. In accordance with the XMCD sum rule analysis, the main component of the irradiation induced ferromagnetism at the FeRh film surface was to be effective spin magnetic moment, and not to be orbital moment. We also confirmed that the surface ferromagnetic state could be produced by thermal annealing of the excessively ion irradiated paramagnetic subsurface of the FeRh thin films. This novel magnetic modification technique by using ion irradiation and subsequent annealing can be a potential tool to control the surface magnetic state of FeRh thin films.

Resilient carbon encapsulation of iron pyrite (FeS2) cathodes in lithium ion batteries

Science.gov (United States)

Yoder, Tara S.; Tussing, Matthew; Cloud, Jacqueline E.; Yang, Yongan

2015-01-01

Converting iron pyrite (FeS2) from a non-cyclable to a cyclable cathode material for lithium ion batteries has been an ongoing challenge in recent years. Herein we report a promising mitigation strategy: wet-chemistry based conformal encapsulation of synthetic FeS2 nanocrystals in a resilient carbon (RC) matrix (FeS2@RC). The FeS2@RC composite was fabricated by dispersing autoclave-synthesized FeS2 nanocrystals in an aqueous glucose solution, polymerizing the glucose in a hydrothermal reactor, and finally heating the polymer/FeS2 composite in a tube furnace to partially carbonize the polymer. The FeS2@RC electrodes showed superior cyclability compared with the FeS2 electrodes, that is, 25% versus 1% of retention at the 20th cycle. Based on electrochemical analysis, XRD study, and SEM characterization, the performance enhancement was attributed to RC's ability to accommodate volume fluctuation, enhance charge transfer, alleviate detrimental side reactions, and suppress loss of the active material. Furthermore, the remaining issues associated with the current system were identified and future research directions were proposed.

Ultra-low cost and highly stable hydrated FePO4 anodes for aqueous sodium-ion battery

Science.gov (United States)

Wang, Yuesheng; Feng, Zimin; Laul, Dharminder; Zhu, Wen; Provencher, Manon; Trudeau, Michel L.; Guerfi, Abdelbast; Zaghib, Karim

2018-01-01

The growing demands for large-scale energy storage devices have put a spotlight on aqueous sodium-ion batteries, which possess a number of highly desirable features, such as sodium abundance, low cost and safety over organic electrolytes. While lots of cathode materials were reported, only few candidate materials like active carbon and NaTi2(PO4)3 were proposed as anodes. It is a long-standing common knowledge that the low cost, non-toxicity, and highly reversible FePO4·2H2O is known as an attractive cathode material for non-aqueous lithium- and sodium-ion batteries, but we demonstrate for the first time that nano-size non-carbon coated amorphous FePO4·2H2O can be used as the anode for an aqueous sodium-ion battery. Its optimum operating voltage (∼2.75 V vs. Na+/Na) avoids hydrogen evolution. The capacity is as high as 80 mAh/g at a rate of 0.5 C in a three-electrode system. The full cell, using the Na0.44MnO2 as cathode, maintained 90% of the capacity at 300 cycles at a rate of 3 C. The calculations also show that its volume change during the intercalation of Na ions is below 2%. Its low cost, high safety, along with its outstanding electrochemical performance makes amorphous FePO4·2H2O a promising anode material for aqueous sodium-ion batteries.

Li-ion batteries from LiFePO{sub 4} cathode and anatase/graphene composite anode for stationary energy storage

Energy Technology Data Exchange (ETDEWEB)

Choi, Daiwon; Wang, Donghai; Viswanathan, Vish V.; Wang, Wei; Nie, Zimin; Zhang, Ji-Guang; Graff, Gordon L.; Liu, Jun; Yang, Zhenguo [Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352 (United States); Bae, In-Tae [Small Scale Systems Integration and Packaging Center, State University of New York at Binghamton, P.O. Box 6000, Binghamton, NY 13902 (United States); Duong, Tien [US Departments of Energy, 1000 Independence Ave., Washington, DC 20858 (United States)

2010-03-15

Li-ion batteries made from LiFePO{sub 4} cathode and anatase TiO{sub 2}/graphene composite anode were investigated for potential application in stationary energy storage. Fine-structured LiFePO{sub 4} was synthesized by a novel molten surfactant approach whereas anatase TiO{sub 2}/graphene nanocomposite was prepared via self-assembly method. The full cell that operated at 1.6 V demonstrated negligible fade even after more than 700 cycles at measured 1 C rate. While with relative lower energy density than traditional Li-ion chemistries interested for vehicle applications, the Li-ion batteries based on LiFePO{sub 4}/TiO{sub 2} combination potentially offers long life and low cost, along with safety, all which are critical to the stationary applications. (author)

An excellent performance anode of ZnFe2O4/flake graphite composite for lithium ion battery

International Nuclear Information System (INIS)

Yao, Lingmin; Hou, Xianhua; Hu, Shejun; Tang, Xiaoqin; Liu, Xiang; Ru, Qiang

2014-01-01

Highlights: • ZnFe 2 O 4 /flake graphite composite was synthesized by hydrothermal method. • The ZnFe 2 O 4 /flake graphite anode demonstrated high initial coulombic efficiency of 87.7%. • The initial discharge /charge capacity was 848 mA h g −1 and 744 mA h g −1 . • The high capacity retention of 98% was obtained for the ZnFe 2 O 4 /flake graphite anode. -- Abstract: An approach of hydrothermal reaction for lithium ion battery was adopted, by which ZnFe 2 O 4 /flake graphite composites with excellent performance could be prepared as anode materials for lithium ion batteries. With nano-sized ZnFe 2 O 4 particles coating on the electrochemical active matrix of flake graphite, the special composites allowed improved electronic conductivity and constructed an expressway for the transport of charges and lithium ions. Thus the ZnFe 2 O 4 /flake graphite anode became a compromise between capacity and cycle ability. The initial discharge–charge capacity was 848 mA h g −1 and 744 mA h g −1 at a constant current density of 100 mA g −1 , respectively. As high as 87.7% of the initial coulombic efficiency was obtained. Additionally, the charge capacity maintained constantly in the range of 720–735 mA h g −1 in following cycles. And a high reversible charge capacity of 730 mA h g −1 could be attained after 100 cycles, with the reversible capacity retention of 98%

Investigation on the Effect of Addition of Fe3+ Ion into the Colloidal AgNPs in PVA Solution and Understanding Its Reaction Mechanism

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Roto Roto

2017-11-01

Full Text Available Analysis of Fe3+ ion present in aqueous solutions is always of interests. Recently, this ion has been analyzed by colorimetric methods using colloid of silver nanoparticles (AgNPs in capping agents of polymers. The reaction mechanism between AgNPs and Fe3+ is still subject to the further investigation. In this work, 1,10-phenanthroline was used to probe the reaction mechanism between AgNPs and Fe3+ ion in the solution. The colloids of AgNPs were prepared in the polyvinyl alcohol (PVA solution and reacted with Fe3+. The colloid surface plasmon absorbance decreases linearly along with the increase in Fe3+ concentration. The addition of 1,10-phenanthroline to mixture changes the solution to red, indicating that the reaction produces Fe2+. This suggests that the reduction of the AgNPs absorbance is the result of oxidation of the Ag nanoparticles along with the reduction of Fe3+.

Probing the failure mechanism of nanoscale LiFePO₄ for Li-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Gu, Meng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL); Shi, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environmental Directorate; Beijing Jiaotong University (China). School of Electrical Engineering, National Active Distribution Network Technology Research Center; Zheng, Jianming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environmental Directorate; Yan, Pengfei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL); Zhang, Ji-guang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environmental Directorate; Wang, Chongmin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)

2015-05-18

LiFePO₄ is a high power rate cathode material for lithium ion battery and shows remarkable capacity retention, featuring a 91% capacity retention after 3300 cycles. In this work, we use high-resolution transmission electron microscopy (HRTEM), energy dispersive x-ray spectroscopy (EDS), and electron energy loss spectroscopy (EELS) to study the gradual capacity fading mechanism of LiFePO₄ materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO₄ cathode shows surface amorphization and loss of oxygen species, which directly contribute to the gradual capacity fading of the battery. The finding is of great importance for the design and improvement of new LiFePO₄ cathode for high-energy and high-power rechargeable battery for electric transportation.

Relationship between bicarbonate ion, pH, and /sup 59/Fe uptake by plants

Energy Technology Data Exchange (ETDEWEB)

Falade, J A

1972-01-01

Iron absorption by barley, pea, and runner bean is stimulated by bicarbonate but inhibited by increasing pH. Bicarbonate stimulates translocation of Fe in barley but inhibits it in pea and bean. Increasing pH stimulates translocation in barley and pea with no effect in bean. The presence of other ions in the external solution appears to inhibit absorption but enhances translocation of Fe in bean and pea. It is concluded that whether or not bicarbonate will induce chlorosis in a plant depends on species and variety.

Recent advances on Fe- and Mn-based cathode materials for lithium and sodium ion batteries

Science.gov (United States)

Zhu, Xiaobo; Lin, Tongen; Manning, Eric; Zhang, Yuancheng; Yu, Mengmeng; Zuo, Bin; Wang, Lianzhou

2018-06-01

The ever-growing market of electrochemical energy storage impels the advances on cost-effective and environmentally friendly battery chemistries. Lithium-ion batteries (LIBs) are currently the most critical energy storage devices for a variety of applications, while sodium-ion batteries (SIBs) are expected to complement LIBs in large-scale applications. In respect to their constituent components, the cathode part is the most significant sector regarding weight fraction and cost. Therefore, the development of cathode materials based on Earth's abundant elements (Fe and Mn) largely determines the prospects of the batteries. Herein, we offer a comprehensive review of the up-to-date advances on Fe- and Mn-based cathode materials for LIBs and SIBs, highlighting some promising candidates, such as Li- and Mn-rich layered oxides, LiNi0.5Mn1.5O4, LiFe1-xMnxPO4, NaxFeyMn1-yO2, Na4MnFe2(PO4)(P2O7), and Prussian blue analogs. Also, challenges and prospects are discussed to direct the possible development of cost-effective and high-performance cathode materials for future rechargeable batteries.

Efficient photocatalytic decolorization of some textile dyes using Fe ions doped polyaniline film on ITO coated glass substrate

International Nuclear Information System (INIS)

Haspulat, Bircan; Gülce, Ahmet; Gülce, Handan

2013-01-01

Highlights: • The PANI/Fe film as photocatalyst was used for the first time. • It was possible to modify the surface roughness and wettability of the PANI films. • The photocatalytic decolorization of four dyes has been investigated. • The photocatalytical activity of the PANI matrix was increased by adding Fe ions. -- Abstract: In this study, the photocatalytic decolorization of four commercial textile dyes with different structures has been investigated using electrochemically synthesized polyaniline and Fe ions doped polyaniline on ITO coated glass substrate as photocatalyst in aqueous solution under UV irradiation for the first time. Scanning electron microscopy, atomic force microscopy, FT-IR spectra, UV–vis spectroscopy measurements were used to characterize the electrochemically synthesized polymer film photocatalyst. Film hydrophilicity was assessed from contact angle measurements. The results show that both of the polymer films exhibit good photocatalytic performance. Surprisingly, it was determined that by using Fe(II) ions during polymerization, it is possible to modify the surface roughness and wettability of the produced polyaniline films which favors their photocatalytic activity in water-based solutions. All four of the used dyes (methylene blue, malachite green, methyl orange and methyl red) were completely decolorizated in 90 min of irradiation under UV light by using Fe ions doped polyaniline at the dye concentration of 1.5 × 10 −5 M, while the decolorization of those dyes were between 43% and 83% by using polyaniline as photocatalyst. Hence, it may be a viable technique for the safe disposal of textile wastewater into waste streams

Electrostatic Self-Assembly of Fe3O4 Nanoparticles on Graphene Oxides for High Capacity Lithium-Ion Battery Anodes

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Jung Kyoo Lee

2013-09-01

Full Text Available Magnetite, Fe3O4, is a promising anode material for lithium ion batteries due to its high theoretical capacity (924 mA h g−1, high density, low cost and low toxicity. However, its application as high capacity anodes is still hampered by poor cycling performance. To stabilize the cycling performance of Fe3O4 nanoparticles, composites comprising Fe3O4 nanoparticles and graphene sheets (GS were fabricated. The Fe3O4/GS composite disks of mm dimensions were prepared by electrostatic self-assembly between negatively charged graphene oxide (GO sheets and positively charged Fe3O4-APTMS [Fe3O4 grafted with (3-aminopropyltrimethoxysilane (APTMS] in an acidic solution (pH = 2 followed by in situ chemical reduction. Thus prepared Fe3O4/GS composite showed an excellent rate capability as well as much enhanced cycling stability compared with Fe3O4 electrode. The superior electrochemical responses of Fe3O4/GS composite disks assure the advantages of: (1 electrostatic self-assembly between high storage-capacity materials with GO; and (2 incorporation of GS in the Fe3O4/GS composite for high capacity lithium-ion battery application.

Nano-sized LiFePO4/C composite with core-shell structure as cathode material for lithium ion battery

International Nuclear Information System (INIS)

Liu, Yang; Zhang, Min; Li, Ying; Hu, Yemin; Zhu, Mingyuan; Jin, Hongming; Li, Wenxian

2015-01-01

Graphical abstract: Nano-sized LiFePO4/C composite with core-shell structure was fabricated via a well-designed approach as cathode material forlithium ion battery. The nano-sized LiFePO4/C composite with whole carbon shell coating layer showed an excellent electrical performance. - Abstract: Nano-sized composite with LiFePO 4 -core and carbon-shell was synthesized via a facile route followed by heat treatment at 650 °C. X-ray diffraction (XRD) shows that the core is well crystallized LiFePO 4 . The electron microscopy (SEM and TEM) observations show that the core-shell structured LiFePO 4 /C composite coating with whole carbon shell layer of ∼2.8 nm, possesses a specific surface area of 51 m 2 g −1 . As cathode material for lithium ion battery, the core-shell LiFePO 4 /C composite exhibits high initial capacity of 161 mAh g −1 at 0.1 C, excellent high-rate discharge capacity of 135 mAh g −1 at 5 C and perfect cycling retention of 99.6% at 100 th cycle. All these promising results should be contributed to the core-shell nanostructure which prevents collapse of the particle structure in the long-term charge and discharge cycles, as well as the large surface area of the nano-sized LiFePO 4 /C composite which enhances the electronic conductivity and shortens the distance of lithium ion diffusion

Three-dimensional core-shell Fe_2O_3 @ carbon/carbon cloth as binder-free anode for the high-performance lithium-ion batteries

International Nuclear Information System (INIS)

Wang, Xiaohua; Zhang, Miao; Liu, Enzuo; He, Fang; Shi, Chunsheng; He, Chunnian; Li, Jiajun; Zhao, Naiqin

2016-01-01

Highlights: • The 3D core-shell Fe_2O_3@C/CC structure is fabricated by simple hydrothermal route. • The composite connected 3D carbon networks consist of carbon cloth, Fe_2O_3 nanorods and outer carbon layer. • The Fe_2O_3@C/CC used as binder-free anode in LIBs, demonstrates excellent performances. - Abstract: A facile and scalable strategy is developed to fabricate three dimensional core-shell Fe_2O_3 @ carbon/carbon cloth structure by simple hydrothermal route as binder-free lithium-ion battery anode. In the unique structure, carbon coated Fe_2O_3 nanorods uniformly disperse on carbon cloth which forms the conductive carbon network. The hierarchical porous Fe_2O_3 nanorods in situ grown on the carbon cloth can effectively shorten the transfer paths of lithium ions and reduce the contact resistance. The carbon coating significantly inhibits pulverization of active materials during the repeated Li-ion insertion/extraction, as well as the direct exposure of Fe_2O_3 to the electrolyte. Benefiting from the structural integrity and flexibility, the nanocomposites used as binder-free anode for lithium-ion batteries, demonstrate high reversible capacity and excellent cyclability. Moreover, this kind of material represents an alternative promising candidate for flexible, cost-effective, and binder-free energy storage devices.

Hierarchical hollow spheres of Fe2O3 @polyaniline for lithium ion battery anodes.

Science.gov (United States)

Jeong, Jae-Min; Choi, Bong Gill; Lee, Soon Chang; Lee, Kyoung G; Chang, Sung-Jin; Han, Young-Kyu; Lee, Young Boo; Lee, Hyun Uk; Kwon, Soonjo; Lee, Gaehang; Lee, Chang-Soo; Huh, Yun Suk

2013-11-20

Hierarchical hollow spheres of Fe2 O3 @polyaniline are fabricated by template-free synthesis of iron oxides followed by a post in- and exterior construction. A combination of large surface area with porous structure, fast ion/electron transport, and mechanical integrity renders this material attractive as a lithium-ion anode, showing superior rate capability and cycling performance. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

International Nuclear Information System (INIS)

Möncke, Doris; Wondraczek, Lothar; Sirotkin, Sergey; Stavrou, Elissaios; Kamitsos, Efstratios I.

2014-01-01

Ionic sulfophosphate liquids of the type ZnO-Na 2 O-Na 2 SO 4 -P 2 O 5 exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature T g and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn 2+ to six-fold around Mn 2+ ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases T g . Raman and infrared spectroscopy show that the structure of these glasses involves only SO 4 2− and PO 4 3− monomers as well as P 2 O 7 4- dimers. Replacement of ZnO by MnO is found to favour PO 4 3− over P 2 O 7 4- species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn 2+ , a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn 2+ ions are present primarily in MnO 6 -clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities

Scalable integration of Li5FeO4 towards robust, high-performance lithium-ion hybrid capacitors.

Science.gov (United States)

Park, Min-Sik; Lim, Young-Geun; Hwang, Soo Min; Kim, Jung Ho; Kim, Jeom-Soo; Dou, Shi Xue; Cho, Jaephil; Kim, Young-Jun

2014-11-01

Lithium-ion hybrid capacitors have attracted great interest due to their high specific energy relative to conventional electrical double-layer capacitors. Nevertheless, the safety issue still remains a drawback for lithium-ion capacitors in practical operational environments because of the use of metallic lithium. Herein, single-phase Li5FeO4 with an antifluorite structure that acts as an alternative lithium source (instead of metallic lithium) is employed and its potential use for lithium-ion capacitors is verified. Abundant Li(+) amounts can be extracted from Li5FeO4 incorporated in the positive electrode and efficiently doped into the negative electrode during the first electrochemical charging. After the first Li(+) extraction, Li(+) does not return to the Li5FeO4 host structure and is steadily involved in the electrochemical reactions of the negative electrode during subsequent cycling. Various electrochemical and structural analyses support its superior characteristics for use as a promising lithium source. This versatile approach can yield a sufficient Li(+)-doping efficiency of >90% and improved safety as a result of the removal of metallic lithium from the cell. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of 1 GeV/n Fe particles on cocaine-stimulated locomotor activity

Science.gov (United States)

Vazquez, M.; Bruneus, M.; Gatley, J.; Russell, S.; Billups, A.

Space travel beyond the Earth's protective magnetic field (for example, to Mars) will involve exposure of astronauts to irradiation by high-energy nuclei such as 56Fe (HZE radiation), which are a component of galactic cosmic rays. These particles have high linear energy transfer (LET) and are expected to irreversibly damage cells they traverse. Our working hypothesis is that long-term behavioral alterations are induced after exposure of the brain to 1 GeV/n iron particles with fluences of 1 to 8 particles/cell targets. Previous studies support this notion but are not definitive, especially with regard to long-term effects. Using the Alternating Gradient Synchrotron (AGS) we expose C57 mice to 1 GeV/n 56Fe radiation (head only) at doses of 0, 15, 30, 60, 120 and 240 cGy. There were originally 19 mice per group. The ability of cocaine to increase locomotor activity in 16 of these animals in response to an intraperitoneal injection of cocaine has been measured so far at 1, 4, 8, 12, 16, 20, 24 and 28 weeks. Cocaine-stimulated locomotor activity was chosen in part because it is a behavioral assay with which we have considerable experience. More importantly, the ability to respond to cocaine is a complex behavior involving many neurotransmitter systems and brain circuits. Therefore, the probability of alteration of this behavior by HZE particles was considered high. However, the central circuit is the nigrostriatal dopamine system, in which dopamine is released in striatum from nerve terminals whose cell bodies are located in the substantia nigra. Cocaine activates behavior by blocking dopamine transporters on striatal nerve terminals and therefore elevating the concentration of dopamine in the synapse. Dopamine activates receptors on striatal GABAergic cells that project via other brain regions to the thalamus. Activation of the motor cortex by glutamatergic projections from the thalamus leads ultimately to increased locomotion. The experimental paradigm involves

Fabrication of highly oriented β-FeSi2 by ion beam sputter deposition

International Nuclear Information System (INIS)

Nakanoya, Takamitsu; Sasase, Masato; Yamamoto, Hiroyuki; Saito, Takeru; Hojou, Kiichi

2002-01-01

We have prepared the 'environmentally friendly' semiconductor, β-FeSi 2 thin films by ion beam sputter deposition method. The temperature of Si (100) substrate during the deposition and total amount of deposited Fe have been changed in order to find the optimum condition of the film formation. The crystallinity and surface morphology of the formed silicides were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. It is understood that the domain of the epitaxially grown β-FeSi 2 increases with the substrate temperature up to 700degC at the fixed amount of deposited Fe (33 nm) by XRD spectra. On the other hand, α-FeSi 2 is appeared and increased with the temperature above 700degC. Granulation of the surface is also observed by SEM images at this temperature region. At the fixed temperature condition (700degC), formation of α phase, which is obtained at the higher temperature compared with β phase, is observed for the fewer deposited samples. These results suggest the possibility of the epitaxially grown β-FeSi 2 formation at the lower (< 700degC) temperature region. (author)

Effects of heavy-ion irradiation on the vortex state in Ba(Fe1-xCox)2As2

International Nuclear Information System (INIS)

Tamegai, T.; Tsuchiya, Y.; Taen, T.; Nakajima, Y.; Okayasu, S.; Sasase, M.

2010-01-01

We report effects of heavy-ion irradiation in Ba(Fe 1-x Co x ) 2 As 2 single crystals. The columnar defects with about 40% of the irradiation dose are confirmed by transmission electron microscopy. Magneto-optical imaging and bulk magnetization measurements reveal strong enhancement of the critical current density in the irradiated region. The vortex creep rate is also strongly suppressed by the columnar defects. Effects of heavy-ion irradiation into Ba(Fe 1-x Co x ) 2 As 2 and cuprate superconductors are compared.

Magnetic and dielectric properties of alkaline earth Ca2+ and Ba2+ ions co-doped BiFeO3 nanoparticles

International Nuclear Information System (INIS)

Yang, C.; Liu, C.Z.; Wang, C.M.; Zhang, W.G.; Jiang, J.S.

2012-01-01

Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles, Bi 0.8 Ca 0.2−x Ba x FeO 3 (x=0–0.20), were prepared by a sol–gel method. The phase structure, grain size, dielectric and magnetic properties of the prepared samples were investigated. The results showed that the lattice structure of the nanoparticles transformed from rhombohedral (x=0) to orthorhombic (x=0.07–0.19) and then to tetragonal (x=0.20) with x increased. The dielectric properties of the nanoparticles were affected by the properties of the substitutional ions as well as the crystalline structure of the samples. The magnetic properties of the nanoparticles were greatly improved and the T N of the nanoparticles was obviously increased. All the Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles presented the high ratio of M r /M from 0.527 to 0.571 and large coercivity from 4.335 to 5.163 KOe. - Highlights: ► Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles were prepared using a sol–gel method. ► The magnetic properties of the nanoparticles are greatly improved. ► The Neel temperature (T N ) of the nanoparticles is greatly increased. ► Doped ions and crystal structure affect the dielectric properties of the nanoparticles.

Efficiency of Chitosan for the Removal of Pb (II, Fe (II and Cu (II Ions from Aqueous Solutions

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Soheil Sobhanardakani

2014-09-01

Full Text Available Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II, Fe(II and Cu(II ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II, Fe(II and Cu(II from aqueous solution. In batch tests, the effects of parameters like pH solution (1.0-8.0, initial metal concentrations (100-1000 mgL-1, contact time (5.0-150 min and adsorbent dose (1.0-7.0 g on the adsorption process were studied. Results: The results showed that the adsorption of Pb(II, Fe(II and Cu(II ions on chitosan strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations and it was found that the removal process followed the Langmuir isotherm and maximum adsorption capacity for the adsorption of Pb(II, Fe(II and Cu(II ions by the chitosan were 55.5mg g−1, 71.4 mg g−1 and 59 mg g−1, respectively, under equilibrium conditions at 25±1 ºC. The adsorption process was found to be well described by the pseudo-second-order rate model. Conclusion: The obtained results showed that chitosan is a readily, available, economic adsorbent and was found suitable for removing Pb(II, Fe(II and Cu(II ions from aqueous solution.

In situ catalytic synthesis of high-graphitized carbon-coated LiFePO4 nanoplates for superior Li-ion battery cathodes.

Science.gov (United States)

Ma, Zhipeng; Fan, Yuqian; Shao, Guangjie; Wang, Guiling; Song, Jianjun; Liu, Tingting

2015-02-04

The low electronic conductivity and one-dimensional diffusion channel along the b axis for Li ions are two major obstacles to achieving high power density of LiFePO4 material. Coating carbon with excellent conductivity on the tailored LiFePO4 nanoparticles therefore plays an important role for efficient charge and mass transport within this material. We report here the in situ catalytic synthesis of high-graphitized carbon-coated LiFePO4 nanoplates with highly oriented (010) facets by introducing ferrocene as a catalyst during thermal treatment. The as-obtained material exhibits superior performances for Li-ion batteries at high rate (100 C) and low temperature (-20 °C), mainly because of fast electron transport through the graphitic carbon layer and efficient Li(+)-ion diffusion through the thin nanoplates.

LiFePO4/polymer/natural graphite: low cost Li-ion batteries

International Nuclear Information System (INIS)

Zaghib, K.; Striebel, K.; Guerfi, A.; Shim, J.; Armand, M.; Gauthier, M

2004-01-01

The aging and performance of natural graphite/PEO-based gel electrolyte/LiFePO 4 cells are reported. The gel polymer electrolytes were produced by electron-beam irradiation and then soaked in a liquid electrolyte. The natural graphite anode in gel electrolyte containing LiBF4-EC/GBL exhibited high reversible capacity (345 mAh/g) and high coulombic efficiency (91%). The LiFePO 4 cathode in the same gel-polymer exhibited a reversible capacity of 160 mAh/g and 93% coulombic efficiency. Better performance was obtained at high-rate discharge with 6% carbon additive in the cathode, however the graphite anode performance suffers at high rate. The Li-ion gel polymer battery shows a capacity fade of 13% after 180 cycles and has poor performance at low temperature due to low diffusion of the lithium to the graphite in the GBL system. The LiFePO 4 /gel/Li system has an excellent rate capacity. LiFePO 4 cathode material is suitable for HEV application

Synthesis and Electrochemical Properties of LiFePO4/C for Lithium Ion Batteries.

Science.gov (United States)

Gao, Hong; Wang, Jiazhao; Yin, Shengyu; Zheng, Hao; Wang, Shengfu; Feng, Chuanqi; Wang, Shiquan

2015-03-01

LiFePO4/C was prepared through a facile rheological phase reaction method by using Fe3(PO4)2, Li3PO4 · 8H2O, and glucose as reactants. The LiFePO4/C samples were characterized by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The electrochemical properties of the samples were investigated. The results show that the LiFePO4/C samples have single-phase olivine-type structure, and their particles feature a spherical shape. The carbon coating on the particles of LiFePO4 is about 1.8% of the LiFePO4/C by weight. The particle size was distributed from 0.2 to 1 µm. The initial discharge capacity of LiFePO4/C reached 154 mA h/g at 0.1 C. The retained discharge capacity of LiFePO4/C was 152.9 mA h g(-1) after 50 cycles. The LiFePO4/C also showed better cycling performance than that of the bare LiPeO4 at a higher charge/discharge rate (1 C). The LIFePO4/C prepared in this way could be a promising cathode material for lithium ion battery application.

Synthesis of three-dimensional rare-earth ions doped CNTs-GO-Fe3O4 hybrid structures using one-pot hydrothermal method

International Nuclear Information System (INIS)

Gao, Guo; Zhang, Qiang; Cheng, Xin-Bing; Sun, Rongjin; Shapter, Joseph G.; Yin, Ting; Cui, Daxiang

2015-01-01

Rechargeable lithium ion batteries (LIBs) are currently the dominant power source for all sorts of electronic devices due to their low cost and high energy density. The cycling stability of LIBs is significantly compromised due to the broad satellite peak for many anode materials. Herein, we develop a facile hydrothermal process for preparing rare-earth (Er, Tm) ions doped three-dimensional (3D) transition metal oxides/carbon hybrid nanocomposites, namely CNTs-GO-Fe 3 O 4 , CNTs-GO-Fe 3 O 4 -Er and CNTs-GO-Fe 3 O 4 -Tm. The GO sheets and CNTs are interlinked by ultrafine Fe 3 O 4 nanoparticles forming three-dimensional (3D) architectures. When evaluated as anode materials for LIBs, the CNTs-GO-Fe 3 O 4 hybrid composites have a bigger broad satellite peak. As for the CNTs-GO-Fe 3 O 4 -Er and CNTs-GO-Fe 3 O 4 -Tm hybrid composites, the broad satellite peak can be completely eliminated. When the current density changes from 5 C back to 0.1 C, the capacity of CNTs-GO-Fe 3 O 4 -Tm hybrid composites can recover to 1023.9 mAhg −1 , indicating an acceptable rate capability. EIS tests show that the charge transfer resistance does not change significantly after 500 cycles, demonstrating that the cycling stability of CNTs-GO-Fe 3 O 4 -Tm hybrid composites are superior to CNTs-GO-Fe 3 O 4 and CNTs-GO-Fe 3 O 4 -Er hybrid structures. - Graphical abstract: One-pot hydrothermal method for synthesis of rare-earth ions doped CNTs-GO-Fe 3 O 4 hybrid structures as anode materials of LIBs have been reported. - Highlights: • We report the synthesis of rare-earth ions doped CNTs-GO-Fe 3 O 4 hybrid structures. • The hybrid structures can improve the cycling stability of lithium storage. • As for anode materials, the broad satellite peak can be completely eliminated. • When the rate return back to 0.1 C, the capacity can recover to 1023.9 mAhg −1 . • After 500 cycles, the hybrid structures still exhibited excellent cycling stability

Changes in cluster magnetism and suppression of local superconductivity in amorphous FeCrB alloy irradiated by Ar"+ ions

International Nuclear Information System (INIS)

Okunev, V.D.; Samoilenko, Z.A.; Szymczak, H.; Szewczyk, A.; Szymczak, R.; Lewandowski, S.J.; Aleshkevych, P.; Malinowski, A.; Gierłowski, P.; Więckowski, J.; Wolny-Marszałek, M.; Jeżabek, M.; Varyukhin, V.N.; Antoshina, I.A.

2016-01-01

We show that cluster magnetism in ferromagnetic amorphous Fe_6_7Cr_1_8B_1_5 alloy is related to the presence of large, D=150–250 Å, α-(Fe Cr) clusters responsible for basic changes in cluster magnetism, small, D=30–100 Å, α-(Fe, Cr) and Fe_3B clusters and subcluster atomic α-(Fe, Cr, B) groupings, D=10–20 Å, in disordered intercluster medium. For initial sample and irradiated one (Φ=1.5×10"1"8 ions/cm"2) superconductivity exists in the cluster shells of metallic α-(Fe, Cr) phase where ferromagnetism of iron is counterbalanced by antiferromagnetism of chromium. At Φ=3×10"1"8 ions/cm"2, the internal stresses intensify and the process of iron and chromium phase separation, favorable for mesoscopic superconductivity, changes for inverse one promoting more homogeneous distribution of iron and chromium in the clusters as well as gigantic (twice as much) increase in density of the samples. As a result, in the cluster shells ferromagnetism is restored leading to the increase in magnetization of the sample and suppression of local superconductivity. For initial samples, the temperature dependence of resistivity ρ(T)~T"2 is determined by the electron scattering on quantum defects. In strongly inhomogeneous samples, after irradiation by fluence Φ=1.5×10"1"8 ions/cm"2, the transition to a dependence ρ(T)~T"1"/"2 is caused by the effects of weak localization. In more homogeneous samples, at Φ=3×10"1"8 ions/cm"2, a return to the dependence ρ(T)~T"2 is observed. - Highlights: • The samples at high dose of ion irradiation become more homogeneous. • Gigantic increase in density of the samples (twice as much) is observed. • Ferromagnetism in large Fe–Cr clusters is restored. • Ferromagnetism of Fe–Cr clusters suppresses local superconductivity in them. • The participation of quantum defects in scattering of electrons is returned.

Preparation and characterization of new cathodic materials for Li-ion battery based polypyrrole-FePO4

International Nuclear Information System (INIS)

Fedorkova, A.; Kaniansky, D.; Orinakova, R.; Orinak, A.

2009-01-01

To investigate the electrochemical properties and stability of our samples, we used cyclic voltammetry and electrochemical impedance spectroscopy. We found that PEG-PPy layer on the particles FePO 4 considerably increased material conductivity in comparison with a layer of pure PPy. It also improved the incorporation of Li + ions into FePO 4 structure during charging and discharging. (Authors)

Efficient reduced graphene oxide grafted porous Fe3O4 composite as a high performance anode material for Li-ion batteries.

Science.gov (United States)

Bhuvaneswari, Subramani; Pratheeksha, Parakandy Muzhikara; Anandan, Srinivasan; Rangappa, Dinesh; Gopalan, Raghavan; Rao, Tata Narasinga

2014-03-21

Here, we report facile fabrication of Fe3O4-reduced graphene oxide (Fe3O4-RGO) composite by a novel approach, i.e., microwave assisted combustion synthesis of porous Fe3O4 particles followed by decoration of Fe3O4 by RGO. The characterization studies of Fe3O4-RGO composite demonstrate formation of face centered cubic hexagonal crystalline Fe3O4, and homogeneous grafting of Fe3O4 particles by RGO. The nitrogen adsorption-desorption isotherm shows presence of a porous structure with a surface area and a pore volume of 81.67 m(2) g(-1), and 0.106 cm(3) g(-1) respectively. Raman spectroscopic studies of Fe3O4-RGO composite confirm the existence of graphitic carbon. Electrochemical studies reveal that the composite exhibits high reversible Li-ion storage capacity with enhanced cycle life and high coulombic efficiency. The Fe3O4-RGO composite showed a reversible capacity ∼612, 543, and ∼446 mA h g(-1) at current rates of 1 C, 3 C and 5 C, respectively, with a coulombic efficiency of 98% after 50 cycles, which is higher than graphite, and Fe3O4-carbon composite. The cyclic voltammetry experiment reveals the irreversible and reversible Li-ion storage in Fe3O4-RGO composite during the starting and subsequent cycles. The results emphasize the importance of our strategy which exhibited promising electrochemical performance in terms of high capacity retention and good cycling stability. The synergistic properties, (i) improved ionic diffusion by porous Fe3O4 particles with a high surface area and pore volume, and (ii) increased electronic conductivity by RGO grafting attributed to the excellent electrochemical performance of Fe3O4, which make this material attractive to use as anode materials for lithium ion storage.

Fe_3C@carbon nanocapsules/expanded graphite as anode materials for lithium ion batteries

International Nuclear Information System (INIS)

Huang, You-Guo; Lin, Xi-Le; Zhang, Xiao-Hui; Pan, Qi-Chang; Yan, Zhi-Xiong; Wang, Hong-Qiang; Chen, Jian-Jun; Li, Qing-Yu

2015-01-01

ABSTRACT: Fe_3C@carbonnanocapsules(*)/expanded graphite composite was successfully prepared by a new and facile method, including mix of starting materials and heat treatment of the precursor. It is featured by unique 3-D structure, where expanded graphite acts as scaffold to ensure a continuous entity, and Fe_3C particles coated by carbon nanocapsules are embedded intimately. The Fe_3C nanoparticles encased in carbon nanocapsules act as catalyst in the modification of SEI film during the cycles. The interesting 3-D architecture which aligns the conductivity paths in the planar direction with expanded graphite and in the axial direction with carbon nanocapsules minimizes the resistance and enhances the reversible capacity. The prepared composite exhibits a high reversible capacity and excellent rate performance as an anode material for lithium ion batteries. The composite maintains a reversible capacity of 1226.2 mAh/g after 75 cycles at 66 mA/g. When the current density increases to 200 mA/g, the reversible capacity maintains 451.5 mAh/g. The facile synthesis method and excellent electrochemical performances make the composite expected to be one of the most potential anode material for lithium ion batteries.

Structural and Electrochemical Characterization of Pure LiFePO4 and Nanocomposite C-LiFePO4 Cathodes for Lithium Ion Rechargeable Batteries

Directory of Open Access Journals (Sweden)

Arun Kumar

2009-01-01

Full Text Available Pure lithium iron phosphate (LiFePO4 and carbon-coated LiFePO4 (C-LiFePO4 cathode materials were synthesized for Li-ion batteries. Structural and electrochemical properties of these materials were compared. X-ray diffraction revealed orthorhombic olivine structure. Micro-Raman scattering analysis indicates amorphous carbon, and TEM micrographs show carbon coating on LiFePO4 particles. Ex situ Raman spectrum of C-LiFePO4 at various stages of charging and discharging showed reversibility upon electrochemical cycling. The cyclic voltammograms of LiFePO4 and C-LiFePO4 showed only a pair of peaks corresponding to the anodic and cathodic reactions. The first discharge capacities were 63, 43, and 13 mAh/g for C/5, C/3, and C/2, respectively for LiFePO4 where as in case of C-LiFePO4 that were 163, 144, 118, and 70 mAh/g for C/5, C/3, C/2, and 1C, respectively. The capacity retention of pure LiFePO4 was 69% after 25 cycles where as that of C-LiFePO4 was around 97% after 50 cycles. These results indicate that the capacity and the rate capability improved significantly upon carbon coating.

Fe3O4/C composite with hollow spheres in porous 3D-nanostructure as anode material for the lithium-ion batteries

Science.gov (United States)

Yang, Zhao; Su, Danyang; Yang, Jinping; Wang, Jing

2017-09-01

3d transition-metal oxides, especially Fe3O4, as anode materials for the lithium-ion batteries have been attracting intensive attentions in recent years due to their high energy capacity and low toxicity. A new Fe3O4/C composite with hollow spheres in porous three-dimensional (3D) nanostructure, which was synthesized by a facile solvothermal method using FeCl3·6H2O and porous spongy carbon as raw materials. The specific surface area and microstructures of composite were characterized by nitrogen adsorption-desorption isotherm method, FE-SEM and HR-TEM. A homogeneous distribution of hollow Fe3O4 spheres (diameter ranges from 120 nm to 150 nm) in the spongy carbon (pore size > 200 nm) conductive 3D-network significantly reduced the lithium-ion diffusion length and increased the electrochemical reaction area, and further more enhanced the lithium ion battery performance, such as discharge capacity and cycle life. As an anode material for the lithium-ion battery, the title composite exhibit excellent electrochemical properties. The Fe3O4/C composite electrode achieved a relatively high reversible specific capacity of 1450.1 mA h g-1 in the first cycle at 100 mA g-1, and excellent rate capability (69% retention at 1000 mA g-1) with good cycle stability (only 10% loss after 100 cycles).

Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Möncke, Doris; Wondraczek, Lothar, E-mail: lothar.wondraczek@uni-jena.de [Otto-Schott-Institute of Materials Research, Friedrich-Schiller-University Jena, Fraunhoferstr. 6, 07743 Jena (Germany); Sirotkin, Sergey [Institut des Sciences Moléculaires - CNRS UMR 5255, Université de Bordeaux, 33405 Talence (France); Stavrou, Elissaios; Kamitsos, Efstratios I. [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constaniou Ave., 116 35 Athens (Greece)

2014-12-14

Ionic sulfophosphate liquids of the type ZnO-Na{sub 2}O-Na{sub 2}SO{sub 4}-P{sub 2}O{sub 5} exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature T{sub g} and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn{sup 2+} to six-fold around Mn{sup 2+} ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases T{sub g}. Raman and infrared spectroscopy show that the structure of these glasses involves only SO{sub 4}{sup 2−} and PO{sub 4}{sup 3−} monomers as well as P{sub 2}O{sub 7}{sup 4-} dimers. Replacement of ZnO by MnO is found to favour PO{sub 4}{sup 3−} over P{sub 2}O{sub 7}{sup 4-} species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn{sup 2+}, a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn{sup 2+} ions are present primarily in MnO{sub 6}-clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities.

Electrochemical properties and lithium ion diffusion in Li4FeSbO6 studied by first principle

Science.gov (United States)

Jia, Mingzhen; Wang, Hongyan; Wang, Hui; Chen, Yuanzheng; Guo, Chunsheng; Gan, Liyong

2017-10-01

Due to the high capacity, Li-rich materials Li2MO3 (M = transition metal) have attracted considerable attention as the next generation of Li-ion batteries. Li4FeSbO6 is a new Li-rich layered oxide material with antiferromagnet honeycomb structure. In this work, the electrochemical behavior, charging process and oxygen stability of LixFeSbO6 (0 ≤ xextracted, the charge compensation is mainly contributed by the oxygen atoms through analyzing the Bader charges of each element. In addition, oxygen evolution reactions will occur in LixFeSbO6 (x ≤ 1.5), which will decay the capacities during cycling process. Finally, we calculated that the lithium ion can diffuse in a three-dimensional pathway with the activation barriers from 0.36 eV to 0.67 eV.

Probing the failure mechanism of nanoscale LiFePO{sub 4} for Li-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Gu, Meng; Yan, Pengfei; Wang, Chongmin, E-mail: chongmin.wang@pnnl.gov [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Shi, Wei [Energy and Environmental Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352 (United States); National Active Distribution Network Technology Research Center, School of Electrical Engineering, Beijing Jiaotong University, 3 Shangyuancun Street, Haidian District, Beijing 100044 (China); Zheng, Jianming; Zhang, Ji-guang [Energy and Environmental Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352 (United States)

2015-05-18

LiFePO{sub 4} is a high power rate cathode material for lithium ion battery and shows remarkable capacity retention, featuring a 91% capacity retention after 3300 cycles. In this work, we use high-resolution transmission electron microscopy and electron energy loss spectroscopy to study the gradual capacity fading mechanism of LiFePO{sub 4} materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO{sub 4} cathode shows surface amorphization and loss of oxygen species, which directly contribute to the gradual capacity fading of the battery. The finding can guide the design and improvement of LiFePO{sub 4} cathode for high-energy and high-power rechargeable battery for electric transportation.

Graphene Modified LiFePO4 Cathode Materials for High Power Lithium ion Batteries

International Nuclear Information System (INIS)

Zhou, X.; Wang, F.; Zhu, Y.; Liu, Z.

2011-01-01

Graphene-modified LiFePO 4 composite has been developed as a Li-ion battery cathode material with excellent high-rate capability and cycling stability. The composite was prepared with LiFePO 4 nanoparticles and graphene oxide nanosheets by spray-drying and annealing processes. The LiFePO 4 primary nanoparticles embedded in micro-sized spherical secondary particles were wrapped homogeneously and loosely with a graphene 3D network. Such a special nanostructure facilitated electron migration throughout the secondary particles, while the presence of abundant voids between the LiFePO 4 nanoparticles and graphene sheets was beneficial for Li + diffusion. The composite cathode material could deliver a capacity of 70 mAh g -1 at 60C discharge rate and showed a capacity decay rate of <15% when cycled under 10C charging and 20C discharging for 1000 times.

Synthesis and electrochemical properties of Na-rich Prussian blue analogues containing Mn, Fe, Co, and Fe for Na-ion batteries

Science.gov (United States)

Bie, Xiaofei; Kubota, Kei; Hosaka, Tomooki; Chihara, Kuniko; Komaba, Shinichi

2018-02-01

Electrochemical performance of Prussian blue analogues (PBAs) as positive electrode materials for non-aqueous Na-ion batteries is known to be highly dependent on their synthesis conditions according to the previous researches. Na-rich PBAs, NaxM[Fe(CN)6]·nH2O where M = Mn, Fe, Co, and Ni, are prepared via precipitation method under the same condition. The structure, chemical composition, morphology, valence of the transition metals, and electrochemical property of these samples are comparatively researched. The PBA with Mn shows large reversible capacity of 126 mAh g-1 in 2.0-4.2 V at a current density of 30 mA g-1 and the highest working voltage owning to high redox potential of Mn2+/3+ in MnN6 and Fe2+/3+ in FeC6. While, the PBA with Ni exhibits the best cyclability and rate performance though only 66 mAh g-1 is delivered. The significant differences in electrochemical behaviors of the PBAs originate from the various properties depending on different transition metals.

Liquid-Solid-Solution Assembly of CoFe2O4/Graphene Nanocomposite as a High-Performance Lithium-Ion Battery Anode

International Nuclear Information System (INIS)

Zhu, Yanfang; Lv, Xingbin; Zhang, Lili; Guo, Xiaodong; Liu, Daijun; Chen, Jianjun; Ji, Junyi

2016-01-01

Graphical abstract: CoFe 2 O 4 /rGO composites are fabricated via a liquid-solid-solution assemble strategy with a well controlled CoFe 2 O 4 size, the composite exhibits a high rate performance for lithium ion batteries anode. - Highlights: • Crumpled CoFe 2 O 4 @graphene composite with uniform CoFe 2 O 4 nanoparticles intimately anchored on graphene sheets was fabricated. • The novel fabrication strategy: liquid-solid-solution strategy where the CoFe 2 O 4 are nucleation and controlled growth at the oil/water interface. • High reversible specific capacity of 1102 mAh g −1 after 100 cycles and high rate capability of 410 mAh g −1 within 230 s charging. - Abstract: CoFe 2 O 4 /graphene composites were fabricated via a novel one-pot liquid-solid-solution (LSS) hydrothermal process. Through ions electrostatic adsorption onto graphene sheets and oil microemulsion encapsulation, CoFe 2 O 4 nanoparticles can be uniformly anchored on crumpled graphene sheets without aggregation, and the size distribution of CoFe 2 O 4 particles can be controlled by the microemulsion shell in the range of 50–100 nm. With the synergistic effect between CoFe 2 O 4 and graphene, the CoFe 2 O 4 /graphene hybrid exhibits a high reversible specific capacity of 1102 mAh g −1 at 0.2 A g −1 after 100 cycles, and a good cycling stability as well. Moreover, the composite has good rate capability. The specific capacity can reach a high value of 410 mAh g −1 even under a high current density of 6.4 A g −1 (corresponds to a charge time of ∼230 s), indicating its promising application as an anode material for lithium ion batteries.

TiO2 nanotubes with different spacing, Fe2O3 decoration and their evaluation for Li-ion battery application

Science.gov (United States)

Ozkan, Selda; Cha, Gihoon; Mazare, Anca; Schmuki, Patrik

2018-05-01

In the present work, we report on the use of organized TiO2 nanotube (NT) layers with a regular intertube spacing for the growth of highly defined α-Fe2O3 nano-needles in the interspace. These α-Fe2O3 decorated TiO2 NTs are then explored for Li-ion battery applications and compared to classic close-packed (CP) NTs that are decorated with various amounts of nanoscale α-Fe2O3. We show that NTs with tube-to-tube spacing allow uniform decoration of individual NTs with regular arrangements of hematite nano-needles. The tube spacing also facilitates the electrolyte penetration as well as yielding better ion diffusion. While bare CP NTs show a higher capacitance of 71 μAh cm-2 compared to bare spaced NTs with a capacitance of 54 μAh cm-2, the hierarchical decoration with secondary metal oxide, α-Fe2O3, remarkably enhances the Li-ion battery performance. Namely, spaced NTs with α-Fe2O3 decoration have an areal capacitance of 477 μAh cm-2, i.e. they have nearly ˜8 times higher capacitance. However, the areal capacitance of CP NTs with α-Fe2O3 decoration saturates at 208 μAh cm-2, i.e. is limited to ˜3 times increase.

Doping effects of Fe ion on magnetic anisotropy of YBa2Cu3Oy

International Nuclear Information System (INIS)

Ugawa, T.; Horii, S.; Maeda, T.; Haruta, M.; Shimoyama, J.

2013-01-01

Highlights: •We clarified orientation effects of Fe-doped Y123 in modulated rotating fields. •Y123 showed two different hard magnetic axes due to twin microstructures. •The two hard magnetic axes in Fe-doped Y123 were [1 0 0] and [1 1 0] directions. •Magnetic anisotropy of the [1 1 0] grain was higher than that of the [1 0 0] grain. -- Abstract: We report magnetic alignment of YBa 2 (Cu 1−x Fe x ) 3 O y (Fe-doped Y123, x = 0–0.1) powders under modulated rotation magnetic fields (MRFs) and roles of Fe ion as a determination factor of magnetic anisotropy in Y123. The Fe-free and Fe-doped Y123 powder samples aligned in the MRF of 10 T showed two different orientation types of the hard axis in Y123 grains. From an X-ray rocking curve measurement for the magnetically aligned powder samples of the Fe-doped Y123, inplane magnetic anisotropy for Y123 grains with the hard axis parallel to the [1 1 0] direction was found to be higher than that for Y123 grains with the hard axis parallel to the [0 1 0] direction

The reaction of hydrogen peroxide with Fe(II) ions at elevated temperatures

DEFF Research Database (Denmark)

Christensen, H.; Sehested, K.; Løgager, T.

1993-01-01

The rate constant for the reaction between Fe(II) ions and H2O2 has been determined at pH 0.4-2 as a function of temperature in the range 5-300-degrees-C. H2O2 was produced by irradiating the aqueous solution with a pulse of electrons. The rate constants at 20 and 300-degrees-C were determined...

Electrical properties of InP:Fe single crystals implanted by phosphorus ions

International Nuclear Information System (INIS)

Radautsan, S.I.; Tiginyanu, I.M.; Pyshnaya, N.B.

1988-01-01

Investigations of phosphorus ion implantation in InP:Fe monocrystals and of the post-implantation annealing process upon the electrical properties of InP:Fe were carried out. The electrical parameters of the samples have been determined by Hall effect measurements. The curves of electron surface concentration n s and mobility μ s as functions of annealing temperature in the range of 200 to 600 0 C are shown and discussed. In order to estimate the depth of donor levels in annealed samples the temperature dependence of the surface Hall coefficient has been studied in the range 100 to 400 K. The thermal electron activation energy has been determined to be 0.09 eV

Relating the 3D electrode morphology to Li-ion battery performance; a case for LiFePO4

Science.gov (United States)

Liu, Zhao; Verhallen, Tomas W.; Singh, Deepak P.; Wang, Hongqian; Wagemaker, Marnix; Barnett, Scott

2016-08-01

One of the main goals in lithium ion battery electrode design is to increase the power density. This requires insight in the relation between the complex heterogeneous microstructure existing of active material, conductive additive and electrolyte providing the required electronic and Li-ion transport. FIB-SEM is used to determine the three phase 3D morphology, and Li-ion concentration profiles obtained with Neutron Depth Profiling (NDP) are compared for two cases, conventional LiFePO4 electrodes and better performing carbonate templated LiFePO4 electrodes. This provides detailed understanding of the impact of key parameters such as the tortuosity for electron and Li-ion transport though the electrodes. The created hierarchical pore network of the templated electrodes, containing micron sized pores, appears to be effective only at high rate charge where electrolyte depletion is hindering fast discharge. Surprisingly the carbonate templating method results in a better electronic conductive CB network, enhancing the activity of LiFePO4 near the electrolyte-electrode interface as directly observed with NDP, which in a large part is responsible for the improved rate performance both during charge and discharge. The results demonstrate that standard electrodes have a far from optimal charge transport network and that significantly improved electrode performance should be possible by engineering the microstructure.

Effect of metal ion Fe(III on the performance of chlorophyll as photosensitizers on dye sensitized solar cell

Directory of Open Access Journals (Sweden)

Harsasi Setyawati

Full Text Available The energy crisis is a major problem facing the world today and will need a renewable energy source that is environmentally friendly; one of these is the dye sensitized solar cell (DSSC. DSSC is photochemical electric cell that can convert solar energy into electrical energy. This research aims to study the characteristics of chlorophyll compounds with the addition of metal ions Fe(III and to determine the effect of Fe(III on the performance of chlorophyll as a photosensitizer in the DSSC. The formation of complex compounds of Fe(III-chlorophyll is shown by the phenomenon of metal ligand charge transfer (MLCT at a wavelength of 263.00 nm and absorption transition d-d at 745.00 nm. Fourier transform infrared characterization of the binding of Fe-O complex compounds appears at 486.06 cm−1. The complex compound of Fe(III-chlorophyll has a magnetic moment value of 9.62 Bohr Magneton (BM. The existence of ion Fe(III in chlorophyll can improve the performance of chlorophyll as a dye sensitizer with a maximum current of 4.00 mA/cm2, maximum voltage of 0.18 volts and efficiency values of 1.35%. Keywords: Fe(III-chlorophyll, Dye sensitized solar cell, Metal ligand charge transfer, Photosensitizer

The structure modification of Si-SiO2 irradiated by Fe+ ion

International Nuclear Information System (INIS)

Jin Tao; Ma Zhongquan; Guo Qi

1992-01-01

The effect of the iron ion implantation on the oxide surface and SiO 2 -Si interface of MOS structure was studied by X-ray photo-electron spectroscopy (XPS), and the chemical states of compounds formed were examined. The results obtained show that in the surface layers of SiO 2 the pure Si micro-regions are formed under the implantation and the interface layers of SiO 2 the pure Si micro-regions are formed under the implantation and the interface thickness is almost doubled that leads to failure of MOS capacitors. The physical and chemical mechanisms of MOS structure change by Fe + ion implantation are also discussed and analyzed

Outstanding Li-storage performance of LiFePO4@MWCNTs cathode material with 3D network structure for lithium-ion batteries

Science.gov (United States)

Sun, Xiaodong; Zhang, Le

2018-05-01

In this work, the MWCNTs-decorated LiFePO4 microspheres (LiFePO4@MWCNTs) with a 3D network structure have been synthesized by a facile and efficient spray-drying approach followed by solid-state reaction in a reduction atmosphere. In the as-prepared composite, the MWCNTs around LiFePO4 nanoparticles can provide 3D conductive networks which greatly facilitate the transport of Li+-ion and electron during the electrochemical reaction. Compared to the pure LiFePO4 material, the LiFePO4@MWCNTs composite as cathode for lithium-ion batteries exhibits significantly improved Li-storage performance in terms of rate capability and cyclic stability. Therefore, we can speculate that the spray-drying approach is a promising route to prepare the high-performance electrode materials with 3D network structure for electrochemical energy storage.

Changes in cluster magnetism and suppression of local superconductivity in amorphous FeCrB alloy irradiated by Ar{sup +} ions

Energy Technology Data Exchange (ETDEWEB)

Okunev, V.D., E-mail: okunev@mail.fti.ac.donetsk.ua [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Samoilenko, Z.A. [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Szymczak, H.; Szewczyk, A.; Szymczak, R.; Lewandowski, S.J.; Aleshkevych, P.; Malinowski, A.; Gierłowski, P.; Więckowski, J. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Wolny-Marszałek, M.; Jeżabek, M. [Institute of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland); Varyukhin, V.N. [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Antoshina, I.A. [Obninsk State Technical University of Atomic Energy, 249020 Obninsk (Russian Federation)

2016-02-01

We show that cluster magnetism in ferromagnetic amorphous Fe{sub 67}Cr{sub 18}B{sub 15} alloy is related to the presence of large, D=150–250 Å, α-(Fe Cr) clusters responsible for basic changes in cluster magnetism, small, D=30–100 Å, α-(Fe, Cr) and Fe{sub 3}B clusters and subcluster atomic α-(Fe, Cr, B) groupings, D=10–20 Å, in disordered intercluster medium. For initial sample and irradiated one (Φ=1.5×10{sup 18} ions/cm{sup 2}) superconductivity exists in the cluster shells of metallic α-(Fe, Cr) phase where ferromagnetism of iron is counterbalanced by antiferromagnetism of chromium. At Φ=3×10{sup 18} ions/cm{sup 2}, the internal stresses intensify and the process of iron and chromium phase separation, favorable for mesoscopic superconductivity, changes for inverse one promoting more homogeneous distribution of iron and chromium in the clusters as well as gigantic (twice as much) increase in density of the samples. As a result, in the cluster shells ferromagnetism is restored leading to the increase in magnetization of the sample and suppression of local superconductivity. For initial samples, the temperature dependence of resistivity ρ(T)~T{sup 2} is determined by the electron scattering on quantum defects. In strongly inhomogeneous samples, after irradiation by fluence Φ=1.5×10{sup 18} ions/cm{sup 2}, the transition to a dependence ρ(T)~T{sup 1/2} is caused by the effects of weak localization. In more homogeneous samples, at Φ=3×10{sup 18} ions/cm{sup 2}, a return to the dependence ρ(T)~T{sup 2} is observed. - Highlights: • The samples at high dose of ion irradiation become more homogeneous. • Gigantic increase in density of the samples (twice as much) is observed. • Ferromagnetism in large Fe–Cr clusters is restored. • Ferromagnetism of Fe–Cr clusters suppresses local superconductivity in them. • The participation of quantum defects in scattering of electrons is returned.

High-Energy-Density Aqueous Magnesium-Ion Battery Based on a Carbon-Coated FeVO4 Anode and a Mg-OMS-1 Cathode.

Science.gov (United States)

Zhang, Hongyu; Ye, Ke; Zhu, Kai; Cang, Ruibai; Yan, Jun; Cheng, Kui; Wang, Guiling; Cao, Dianxue

2017-12-01

Porous FeVO 4 is prepared by hydrothermal method and further modified by coating with carbon to obtain FeVO 4 /C with a hierarchical pore structure. FeVO 4 /C is used as an anodic electrode in aqueous rechargeable magnesium-ion batteries. The FeVO 4 /C material not only has improved electrical conductivity as a result of the carbon coating layer, but also has an increased specific surface area as a result of the hierarchical pore structure, which is beneficial for magnesium-ion insertion/deinsertion. Therefore, an aqueous rechargeable magnesium-ion full battery is successfully constructed with FeVO 4 /C as the anode, Mg-OMS-1 (OMS=octahedral molecular sieves) as the cathode, and 1.0 mol L -1 MgSO 4 as the electrolyte. The discharge capacity of the Mg-OMS-1//FeVO 4 /C aqueous battery is 58.9 mAh g -1 at a current density of 100 mA g -1 ; this value is obtained by calculating the total mass of two electrodes and the capacity retention rate of this device is 97.7 % after 100 cycles, with almost 100 % coulombic efficiency, which indicates that the system has a good electrochemical reversibility. Additionally, this system can achieve a high energy density of 70.4 Wh kg -1 , which provides powerful evidence that an aqueous magnesium-ion battery is possible. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Corrosion properties of aluminium coatings deposited on sintered NdFeB by ion-beam-assisted deposition

Energy Technology Data Exchange (ETDEWEB)

Mao Shoudong; Yang Hengxiu; Li Jinlong; Huang Feng [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 519 Zhuangshi Road, Ningbo 315201 (China); Song Zhenlun, E-mail: songzhenlun@nimte.ac.cn [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 519 Zhuangshi Road, Ningbo 315201 (China)

2011-04-15

Pure Al coatings were deposited by direct current (DC) magnetron sputtering to protect sintered NdFeB magnets. The effects of Ar{sup +} ion-beam-assisted deposition (IBAD) on the structure and the corrosion behaviour of Al coatings were investigated. The Al coating prepared by DC magnetron sputtering with IBAD (IBAD-Al-coating) had fewer voids than the coating without IBAD (Al-coating). The corrosion behaviour of the Al-coated NdFeB specimens was investigated by potentiodynamic polarisation, a neutral salt spray (NSS) test, and electrochemical impedance spectroscopy (EIS). The pitting corrosion of the Al coatings always began at the voids of the grain boundaries. Bombardment by the Ar{sup +} ion-beams effectively improved the corrosion resistance of the IBAD-Al-coating.

Formation mechanism and yield of molecules ejected from ZnS, CdS, and FeS2 during ion bombardment

International Nuclear Information System (INIS)

Nikzad, S.; Calaway, W.F.; Pellin, M.J.; Young, C.E.; Gruen, D.M.; Tombrello, T.A.

1994-01-01

Neutral species ejected from single crystals of ZnS, CdS, and FeS 2 during ion bombardment by 3 keV Ar + were detected by laser post-ionization followed by time-of-flight mass spectrometry. While metal atoms (Fe, Zn, Cd) and S 2 were the dominant species observed, substantial amounts of S, FeS, Zn 2 , ZnS, Cd 2 , and CdS were also detected. The experimental results demonstrate that molecules represent a larger fraction of the sputtered yield than was previously believed from secondary ion mass spectrometry experiments. In addition, the data suggest that the molecules are not necessarily formed from adjacent atoms in the solid and that a modified form of the recombination model could provide a mechanism for their formation

Identification of biomarkers of radioresponse and subsequent progression towards lung cancer in normal human bronchial epithelial cells after HZE particle irradiation

Science.gov (United States)

Story, Michael; Ding, Liang-Hao; Park, Seongmi; Minna, John

Using variants of a non-oncogenically immortalized human bronchial epithelial cell line HBEC3-KT, we have examined global gene expression patterns after low and high LET irradiation up to 24h post-IR. Using supervised analyses we have identified 427 genes whoes expression can be used to discriminate the cellular response to γ-vs Si or Fe particles even when the biological outcome, cell death, is equivalent. Furthermore, genetic background also determines gene expression response. When HBEC3-KT is compared to the HBEC3-KT cells line where mutant k-RAS is over-expressed and p53 has been knocked down, HBEC-3KTr53, principal component analysis clearly shows that the response of each cell resides in a different 3-D space, that is, basal gene expression patterns as well as the gene expression response are unique to each cell type. Using regression analysis to examine these 427 genes show clusters of genes whose temporal expression patterns are the same and which are unique to a given radiation type. Ultimately, this approach will allow for the interrogation of gene promoters to identify response elements that drive how cells respond to different radiation types. We are extending our examination to O particles and are now examining gene expression as a function of beam quality. We have made substantial progress in the determination of cellular transformation by HZE particles for these cell lines. (Transformation as defined by the ability to grow in soft agar.) For HBEC-3KT, the spontaneous transformation frequency is about 10- 7.ExposuretoeitherF eorSiparticlesinc KT r53celllinedidnotshowanyincreaseintransf ormationf requencyaf terdosesof upto1Gy, however, thesp 3KT.W ehavenowisolatedover160individualf ocithatf ormedinsof tagarf romcellculturesthatwereirradia termcultureandthenre-introducedintosof tagartoassurethattheabilitytogrowinsof tagarisclonal.T odatew 30 With these cell isolates in hand we will begin to determine tumorigenicity by subcutaneous injections in nude

Mechanistic insights into the interaction between energetic oxygen ions and nanosized ZnFe2O4: XAS-XMCD investigations.

Science.gov (United States)

Singh, Jitendra Pal; Kaur, Baljeet; Sharma, Aditya; Kim, So Hee; Gautam, Sanjeev; Srivastava, Ramesh Chandra; Goyal, Navdeep; Lim, Weol Cheol; Lin, H-J; Chen, J M; Asokan, K; Kanjilal, D; Won, Sung Ok; Lee, Ik-Jae; Chae, Keun Hwa

2018-04-20

The interactions of energetic ions with multi-cation compounds and their consequences in terms of changes in the local electronic structure, which may facilitate intriguing hybridization between O 2p and metal d orbitals and magnetic ordering, are the subject of debate and require a deep understanding of energy transfer processes and magnetic exchange mechanisms. In this study, nanocrystals of ZnFe2O4 were exposed to O7+ ions with an energy of 100 MeV to understand, qualitatively and quantitatively, the metal-ligand field interactions, cation migration and magnetic exchange interactions by employing X-ray absorption fine structure measurements and X-ray magnetic circular dichroism to get deeper mechanistic insights. Nanosized zinc ferrite nanoparticles (NPs) with a size of ∼16 nm synthesized in the cubic spinel phase exhibited deterioration of the crystalline phase when 100 MeV O7+ ions passed through them. However, the size of these NPs remained almost the same. The behaviour of crystal deterioration is associated with the confinement of heat in this interaction. The energy confined inside the nanoparticles promotes cation redistribution as well as the modification of the local electronic structure. Prior to this interaction, almost 42% of Zn2+ ions occupied AO4 tetrahedra; however, this value increased to 63% after the interaction. An inverse effect was observed for metal ion occupancies in BO6 octahedra. The L-edge spectra of Fe and Zn reveal that the spin and valence states of the metal ions were not affected by this interaction. This effect is also supported by K-edge measurements for Fe and Zn. The t2g/eg intensity ratio in the O K-edge spectra decreased after this interaction, which is associated with detachment of Zn2+ ions from the lattice. The extent of hybridization, as estimated from the ratio of the post-edge to the pre-edge region of the O K-edge spectra, decreased after this interaction. The metal-oxygen and metal-metal bond lengths were modified

Electrochemical dissolution of fresh and passivated chalcopyrite electrodes. Effect of pyrite on the reduction of Fe3+ ions and transport processes within the passive film

International Nuclear Information System (INIS)

Olvera, O.G.; Quiroz, L.; Dixon, D.G.; Asselin, E.

2014-01-01

Graphical abstract: - Highlights: • FeS 2 increased the dissolution rate of fresh and passivated CuFeS 2 electrodes. • Fe 3+ reduction was the rate controlling step in the dissolution of fresh CuFeS 2 . • Diffusion within the passive film controlled the dissolution rate of passivated CuFeS 2 . - Abstract: The effect of pyrite (FeS 2 ) on the electrochemical dissolution of fresh and passivated chalcopyrite (CuFeS 2 ) electrodes has been studied. Current density values for the dissolution of CuFeS 2 were calculated from EIS measurements. FeS 2 increased the dissolution rate of fresh and passivated CuFeS 2 electrodes indicating that the galvanic effect continued even after the electrode was chemically passivated. The dissolution rate of CuFeS 2 decreased by a factor of 3 after the passivation treatment. Due to the low diffusion rates of ions within the CuFeS 2 passive film and due to an increase in the resistance to the transfer of electrons at the electrode/film interface, the activity of FeS 2 for the reduction of Fe 3+ ions was also reduced by a factor of 2.3 even though FeS 2 was not exposed to any chemical treatment. The results in this work indicate that the dissolution rate of the fresh CuFeS 2 electrode was controlled by the reduction of Fe 3+ ions whereas for the passivated CuFeS 2 electrode the dissolution rate was controlled by diffusion within the passive film

Synthesis of LiFePO4/Graphene Nanocomposite and Its Electrochemical Properties as Cathode Material for Li-Ion Batteries

Directory of Open Access Journals (Sweden)

Xiaoling Ma

2015-01-01

Full Text Available LiFePO4/graphene nanocomposite was successfully synthesized by rheological phase method and its electrochemical properties as the cathode materials for lithium ion batteries were measured. As the iron source in the synthesis, FeOOH nanorods anchored on graphene were first synthesized. The FeOOH nanorods precursors and the final LiFePO4/graphene nanocomposite products were characterized by XRD, SEM, and TEM. While the FeOOH precursors were nanorods with 5–10 nm in diameter and 10–50 nm in length, the LiFePO4 were nanoparticles with 20–100 nm in size. Compared with the electrochemical properties of LiFePO4 particles without graphene nanosheets, it is clear that the graphene nanosheets can improve the performances of LiFePO4 as the cathode material for lithium ion batteries. The as-synthesized LiFePO4/graphene nanocomposite showed high capacities and good cyclabilities. When measured at room temperature and at the rate of 0.1C (1C = 170 mA g−1, the composite showed a discharge capacity of 156 mA h g−1 in the first cycle and a capacity retention of 96% after 15 cycles. The improved performances of the composite are believed to be the result of the three-dimensional conducting network formed by the flexible and planar graphene nanosheets.

Synthesis of Microspherical LiFePO4-Carbon Composites for Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Maria-Magdalena Titirici

2013-07-01

Full Text Available This paper reports an “all in one” procedure to produce mesoporous, micro-spherical LiFePO4 composed of agglomerated crystalline nanoparticles. Each nanoparticle is individually coated with a thin glucose-derived carbon layer. The main advantage of the as-synthesized materials is their good performance at high charge-discharge rates. The nanoparticles and the mesoporosity guarantee a short bulk diffusion distance for both lithium ions and electrons, as well as additional active sites for the charge transfer reactions. At the same time, the thin interconnected carbon coating provides a conductive framework capable of delivering electrons to the nanostructured LiFePO4.

High Performance Lithium-Ion Hybrid Capacitors Employing Fe3O4-Graphene Composite Anode and Activated Carbon Cathode.

Science.gov (United States)

Zhang, Shijia; Li, Chen; Zhang, Xiong; Sun, Xianzhong; Wang, Kai; Ma, Yanwei

2017-05-24

Lithium-ion capacitors (LICs) are considered as promising energy storage devices to realize excellent electrochemical performance, with high energy-power output. In this work, we employed a simple method to synthesize a composite electrode material consisting of Fe 3 O 4 nanocrystallites mechanically anchored among the layers of three-dimensional arrays of graphene (Fe 3 O 4 -G), which exhibits several advantages compared with other traditional electrode materials, such as high Li storage capacity (820 mAh g -1 at 0.1 A g -1 ), high electrical conductivity, and improved electrochemical stability. Furthermore, on the basis of the appropriated charge balance between cathode and anode, we successfully fabricated Fe 3 O 4 -G//activated carbon (AC) soft-packaging LICs with a high energy density of 120.0 Wh kg -1 , an outstanding power density of 45.4 kW kg -1 (achieved at 60.5 Wh kg -1 ), and an excellent capacity retention of up to 94.1% after 1000 cycles and 81.4% after 10 000 cycles. The energy density of the Fe 3 O 4 -G//AC hybrid device is comparable with Ni-metal hydride batteries, and its capacitive power capability and cycle life is on par with supercapacitors (SCs). Therefore, this lithium-ion hybrid capacitor is expected to bridge the gap between Li-ion battery and SCs and gain bright prospects in next-generation energy storage fields.

Synthesis of LiFePO4/Graphene Nano composite and Its Electrochemical Properties as Cathode Material for Li-Ion Batteries

International Nuclear Information System (INIS)

Ma, X.; Chen, G.; Liu, Q.; Zeng, G.; Wu, T.

2014-01-01

LiFePO 4 /graphene nano composite was successfully synthesized by rheological phase method and its electrochemical properties as the cathode materials for lithium ion batteries were measured. As the iron source in the synthesis, FeOOH nano rods anchored on graphene were first synthesized. The FeOOH nano rods precursors and the final LiFePO 4 /graphene nano composite products were characterized by XRD, SEM, and TEM. While the FeOOH precursors were nano rods with 5-10 nm in diameter and 10-50 nm in length, the LiFePO 4 were nanoparticles with 20-100 nm in size. Compared with the electrochemical properties of LiFePO 4 particles without graphene nano sheets, it is clear that the graphene nano sheets can improve the performances of LiFePO 4 as the cathode material for lithium ion batteries. The as-synthesized LiFePO 4 /graphene nano composite showed high capacities and good cyclabilities. When measured at room temperature and at the rate of 0.1 C (1 C = 170 mA g -1 ), the composite showed a discharge capacity of 156 mA h g -1 in the first cycle and a capacity retention of 96% after 15 cycles. The improved performances of the composite are believed to be the result of the three-dimensional conducting network formed by the flexible and planar graphene nano sheets.

In-situ synthesis of monodisperse micro-nanospherical LiFePO4/carbon cathode composites for lithium-ion batteries

Science.gov (United States)

Gong, Hao; Xue, Hairong; Wang, Tao; He, Jianping

2016-06-01

The LiFePO4 is recognized as the promising cathode material, due to its high specific capacity, excellent, structural stability and environmental benignity. However, it is blamed for the low tap density and poor rate performance when served as the cathode materials for a long time. Here, the microspheric LiFePO4/C composites are successfully synthesized through a one-step in-situ solvothermal method combined with carbothermic reduction. These LiFePO4/C microspheres are assembled by LiFePO4 nanoparticles (∼100 nm) and uniformly coated by the carbon, which show a narrow diameter distribution of 4 μm. As a cathode material for lithium ion batteries, the LiFePO4/C composites can deliver an initiate charge capacity of 155 mAh g-1 and retain 90% of initial capacity after 200 cycles at 0.1 C. When cycled at high current densities up to 20 C, it shows a discharge capacity of ∼60 mAh g-1, exhibiting superior rate performance. The significantly improved electrochemical performance of LiFePO4/C composites material can be attributed to its special micro-nano hierarchical structure. Microspheric LiFePO4/C composites exhibit a high tap density about 1.3 g cm-3. What's more, the well-coated carbon insures the high electrical conductivity and the nano-sized LiFePO4/C particles shorten lithium ion transport, thus exhibiting the high specific capacity, high cycling stability and good rate performance.

GXRD study of 100 MeV Fe9+ ion irradiated indium phosphide

International Nuclear Information System (INIS)

Dubey, R.L.; Dubey, S.K.; Kachhap, N.K.; Kanjilal, D.

2014-01-01

Swift heavy ions with MeV to GeV kinetic energy offer unique possibilities of modifying material properties. Each projectile passing through the target material causes loss of its energy by ion-electrons and ion-atoms interaction with the target material. The consequence of formal one is to change in surface properties and latter to produces damage deep in the target material near the projected range of projectile. In the present work, indium phosphide samples were irradiated at 100 MeV 56 Fe 9+ ions with different fluences varying from 1x10 12 to 1x10 14 ions cm -2 using the 15UD Pelletron facilities at Inter University Accelerator Centre (IUAC), New Delhi. Grazing angle X-ray diffraction technique was used to investigate the structural properties of irradiated indium phosphide at different depths. The GXRD spectra of non-irradiated and irradiated samples were recorded at different grazing angle i.e 1°, 2°, 3°, 4° and 5° to get the structural information over the projected range. The detailed result will be presented and discussed in the conference. (author)

Three-dimensional core-shell Fe{sub 2}O{sub 3} @ carbon/carbon cloth as binder-free anode for the high-performance lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaohua; Zhang, Miao [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Liu, Enzuo, E-mail: ezliu@tju.edu.cn [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China); He, Fang; Shi, Chunsheng [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); He, Chunnian [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China); Li, Jiajun [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300350 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300350 (China)

2016-12-30

Highlights: • The 3D core-shell Fe{sub 2}O{sub 3}@C/CC structure is fabricated by simple hydrothermal route. • The composite connected 3D carbon networks consist of carbon cloth, Fe{sub 2}O{sub 3} nanorods and outer carbon layer. • The Fe{sub 2}O{sub 3}@C/CC used as binder-free anode in LIBs, demonstrates excellent performances. - Abstract: A facile and scalable strategy is developed to fabricate three dimensional core-shell Fe{sub 2}O{sub 3} @ carbon/carbon cloth structure by simple hydrothermal route as binder-free lithium-ion battery anode. In the unique structure, carbon coated Fe{sub 2}O{sub 3} nanorods uniformly disperse on carbon cloth which forms the conductive carbon network. The hierarchical porous Fe{sub 2}O{sub 3} nanorods in situ grown on the carbon cloth can effectively shorten the transfer paths of lithium ions and reduce the contact resistance. The carbon coating significantly inhibits pulverization of active materials during the repeated Li-ion insertion/extraction, as well as the direct exposure of Fe{sub 2}O{sub 3} to the electrolyte. Benefiting from the structural integrity and flexibility, the nanocomposites used as binder-free anode for lithium-ion batteries, demonstrate high reversible capacity and excellent cyclability. Moreover, this kind of material represents an alternative promising candidate for flexible, cost-effective, and binder-free energy storage devices.

Effect of Iron Fe (II and Fe (III in a Binary System Evaluated Bioluminescent Method

Directory of Open Access Journals (Sweden)

Elena Sorokina

2013-01-01

Full Text Available The effect of iron ions Fe2+ and Fe3+ on the bioluminescent recombinant strain of Escherichia coli in a single-component and binary system. Found that for the bacteria E. coli Fe3+ ions are more toxic than Fe2+. Under the combined effect of iron toxicity increases, the percentage of luminescence quenching increases, but the value is much less than the sum of the indicator for the Fe2+ and Fe3+. The biological effect of insertion of iron is not proportional to their content in the mixture.

Uniform Fe3O4 microflowers hierarchical structures assembled with porous nanoplates as superior anode materials for lithium-ion batteries

DEFF Research Database (Denmark)

Wang, Xiaoliang; Liu, Yanguo; Arandiyan, Hamidreza

2016-01-01

as anode material for lithium-ion batteries, the as-prepared Fe3O4 microflowers electrodes delivered superior capacity, better cycling stability and rate capability than that of Fe3O4 microspheres electrodes. The improved electrochemical performance was attributed to the microscale flowerlike architecture...

Structural and Electrical Properties of Lithium-Ion Rechargeable Battery Using the LiFePO4/Carbon Cathode Material.

Science.gov (United States)

Kim, Young-Sung; Jeoung, Tae-Hoon; Nam, Sung-Pill; Lee, Seung-Hwan; Kim, Jea-Chul; Lee, Sung-Gap

2015-03-01

LiFePO4/C composite powder as cathode material and graphite powder as anode material for Li-ion batteries were synthesized by using the sol-gel method. An electrochemical improvement of LiFePO4 materials has been achieved by adding polyvinyl alcohol as a carbon source into as-prepared materials. The samples were characterized by elemental analysis (EA), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-EM). The chemical composition of LiFePO4/C powders was in a good agreement with that of the starting solution. The capacity loss after 500 cycles of LiFePO4/C cell is 11.1% in room temperature. These superior electrochemical properties show that LiFePO4/C composite materials are promising candidates as cathode materials.

Zirconium hydrides and Fe redistribution in Zr-2.5%Nb alloy under ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Idrees, Y.; Yao, Z. [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, Canada, K7L 3N6 (Canada); Cui, J.; Shek, G.K. [Kinetrics, Mississauga, ON (Canada); Daymond, M.R., E-mail: daymond@queensu.ca [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, Canada, K7L 3N6 (Canada)

2016-11-15

Zr-2.5%Nb alloy is used to fabricate the pressure tubes of the CANDU reactor. The pressure tube is the primary pressure boundary for coolant in the CANDU design and is susceptible to delayed hydride cracking, reduction in fracture toughness upon hydride precipitation and potentially hydride blister formation. The morphology and nature of hydrides in Zr-2.5%Nb with 100 wppm hydrogen has been investigated using transmission electron microscopy. The effect of hydrides on heavy ion irradiation induced decomposition of the β phase has been reported. STEM-EDX mapping was employed to investigate the distribution of alloying elements. The results show that hydrides are present in the form of stacks of different sizes, with length scales from nano- to micro-meters. Heavy ion irradiation experiments at 250 °C on as-received and hydrided Zr-2.5%Nb alloy, show interesting effects of hydrogen on the irradiation induced redistribution of Fe. It was found that Fe is widely redistributed from the β phase into the α phase in the as-received material, however, the loss of Fe from the β phase and subsequent precipitation is retarded in the hydrided material. This preliminary work will further the current understanding of microstructural evolution of Zr based alloys in the presence of hydrogen. - Graphical abstract: STEM HAADF micrographs at low magnification showing the hydride structure in Zr-2.5Nb alloy.

Adsorption of ions on hematite (α-Fe2O3) : a colloid-chemical study

NARCIS (Netherlands)

Breeuwsma, A.

1973-01-01

This study is primarily intended to provide a better understanding of the adsorption of ions on hematite (α-Fe ₂ O ₃ ). In addition, due attention is given to the relation between the ionic adsorption and the colloidal stability of hematite sols.

Chapter 1. is concerned

Continuous preparation of Fe3O4 nanoparticles through Impinging Stream-Rotating Packed Bed reactor and their electrochemistry detection toward heavy metal ions

International Nuclear Information System (INIS)

Fan, Hong-Lei; Zhou, Shao-Feng; Gao, Jing; Liu, You-Zhi

2016-01-01

We reported the continuous preparation and electrochemical behavior toward heavy metal ions of the Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs). This Fe 3 O 4 NPs were fabricated through a novel Impinging Stream-Rotating Packed Bed reactor with a high production rate of 2.23 kg/hour. The as-prepared Fe 3 O 4 NPs were quasi-spherical with a mean diameter of about 10 nm and shown the characteristics of superparamagnetism with the saturated magnetization of 60.5 emu/g. The electrochemical characterization of the as-prepared Fe 3 O 4 NPs toward heavy metal ions were evaluated using square wave anodic stripping voltammetry (SWASV) analysis. The results indicated that the modified electrode could be used to individual detection of Pb(II), Cu(II), Hg(II) and Cd(II). In particular, the modified electrode exhibited the selective detection toward Pb(II) with higher sensitivity of 14.9 μA/μM, while the response to Cu(II), Hg(II) and Cd(II) were negligible. Besides, the modified electrode shown good stability and potential practical applicability in the electrochemical determination of Pb(II). This above results offered a simple method for continuous preparation sensing materials in the application field of electrochemical detection of toxic metal ions through the technology of process intensification. - Highlights: • Fe 3 O 4 nanoparticles were continuous prepared through IS-RPB reactor. • The Fe 3 O 4 nanoparticles showed selective detection of heavy metal ions. • It exhibited favorable sensitivity (14.9 μA μM −1 ) and LOD (0.119 μM) for Pb(II). • The as-prepared nanoparticles showed favorable potential application.

On the role of Fe ions on magnetic properties of doped TiO2 nanoparticles

Science.gov (United States)

Tolea, F.; Grecu, M. N.; Kuncser, V.; Constantinescu, S. Gr.; Ghica, D.

2015-04-01

The role of iron doping on magnetic properties of hydrothermal anatase TiO2:57Fe (0-1 at. %) nanoparticles is investigated by combining superconducting quantum interference device magnetometry with Mössbauer and electron paramagnetic resonance techniques. The results on both as-prepared and thermally treated samples in reduced air atmosphere reveal complexity of magnetic interactions, in connection to certain iron ion electron configurations and defects (oxygen vacancies, F-center, and Ti3+ ions). The distribution of iron ions is predominantly at nanoparticle surface layers. Formation of weak ferromagnetic domains up to 380 K is mainly related to defects, supporting the bound magnetic polaron model.

Polymorphs of LiFeSO4F as cathode materials for lithium ion batteries - a first principle computational study.

Science.gov (United States)

Chung, Sai Cheong; Barpanda, Prabeer; Nishimura, Shin-Ichi; Yamada, Yuki; Yamada, Atsuo

2012-06-28

We have investigated polymorphs of LiFeSO4F, tavorite and triplite, which have been reported as cathode materials for lithium ion batteries. The predicted voltages are 3.64 and 3.90 V for tavorite and triplite, respectively, which agreed excellently with experimental data. It is found that the lithiated states (LiFeSO4F) of the polymorphs are almost degenerate in energy. The difference in voltage is mainly due to the difference in the stabilities of the delithiated states (FeSO4F). This is rationalized by the Fe(3+)-Fe(3+) repulsion in the edge sharing geometry of the triplite structure.

Metal Fe3+ ions assisted synthesis of highly monodisperse Ag/SiO2 nanohybrids and their antibacterial activity

International Nuclear Information System (INIS)

Zhang, Nianchun; Xue, Feng; Yu, Xiang; Zhou, Huihua; Ding, Enyong

2013-01-01

Graphical abstract: TEM images of the Ag/SiO 2 -2 nanohybrids. The homogeneous and more mono-disperse Ag nanoparticles deposit on SiO 2 spheres. Through this method, Ag nanoparticles are easily formed on the surface of SiO 2 compared to other methods. Highlights: ► We prepared homogeneous and mono-dispersed Ag/SiO 2 -2 nanohybrids by adding Fe 3+ ions. ► The Ag/SiO 2 -2 nanohybrids had core(SiO 2 )-shell(Ag) structure. ► The Ag/SiO 2 -2 nanohybrids exhibited excellent antibacterial activity against bacteria. ► The reaction temperature was lower and the yield of Ag/SiO 2 -2 nanohybrids were higher. - Abstract: Highly monodispersed Ag/SiO 2 nanohybrids with excellent antibacterial property were synthesized by using DMF as a reducing agent and employing an additional redox potential of metal Fe 3+ ion as a catalytic agent. The obtained Ag/SiO 2 -2 nanohybrids of about 240 nm were highly monodispersity and uniformity by adding trace Fe 3+ ions into the reaction which Ag + reacted with N,N-dimethyl formamide (DMF) at 70 °C. Compared to the conventional techniques, which need long time and high temperature for silica coating of Ag nanoparticles, this new method was capable of synthesizing monodispersed, uniform, high yield Ag/SiO 2 nanohybrids. The electron was transferred from the Fe 2+ ion to the Ag + ion to accelerate the nucleation of silver nanoparticles. The chemical structures, morphologies and properties of the Ag/SiO 2 nanohybrids were characterized by X-ray diffraction (XRD), (High-resolution, Scanning transmission) transmission electron microscopy (TEM, HRTEM and STEM), and X-ray photoelectron spectroscopy (XPS), and UV–vis spectroscopy (UV–vis) and test of antibacterial. The results demonstrated that the silver nanoparticles supported on the surface of SiO 2 spheres in Ag/SiO 2 -2 nanohybrids structure, the Ag nanoparticles were homogeneous and monodispersed. The results also indicated that the Ag/SiO 2 -2 nanohybrid had excellent antibacterial.

LiCaFeF6: A zero-strain cathode material for use in Li-ion batteries

Science.gov (United States)

de Biasi, Lea; Lieser, Georg; Dräger, Christoph; Indris, Sylvio; Rana, Jatinkumar; Schumacher, Gerhard; Mönig, Reiner; Ehrenberg, Helmut; Binder, Joachim R.; Geßwein, Holger

2017-09-01

A new zero-strain LiCaFeF6 cathode material for reversible insertion and extraction of lithium ions is presented. LiCaFeF6 is synthesized by a solid-state reaction and processed to a conductive electrode composite via high-energy ball-milling. In the first cycle, a discharge capacity of 112 mAh g-1 is achieved in the voltage range from 2.0 V to 4.5 V. The electrochemically active redox couple is Fe3+/Fe2+ as confirmed by Mössbauer spectroscopy and X-ray absorption spectroscopy. The compound has a trigonal colquiriite-type crystal structure (space group P 3 bar 1 c). By means of in situ and ex situ XRD as well as X-ray absorption fine structure spectroscopy a reversible response to Li uptake/release is found. For an uptake of 0.8 mol Li per formula unit only minimal changes occur in the lattice parameters causing a total change in unit cell volume of less than 0.5%. The spatial distribution of cations in the crystal structure as well as the linkage between their corresponding fluorine octahedra is responsible for this very small structural response. With its zero-strain behaviour this material is expected to exhibit only negligible mechanical degradation. It may be used as a cathode material in future lithium-ion batteries with strongly improved safety and cycle life.

A porous C/LiFePO4/multiwalled carbon nanotubes cathode material for Lithium ion batteries

International Nuclear Information System (INIS)

Qin, Guohui; Ma, Qianqian; Wang, Chengyang

2014-01-01

Highlights: •C/LiFePO 4 /MWCNT was synthesized by a incorporation of sol-gel approach and an electro-polymerization progress with a subsequent carbonization progress. •The prepared C/LiFePO 4 /MWCNTs electrode presents high-rate ability, cyclic stability, and a relative volume density. •Such cathode material is an alternative candidate for high power lithium ion batteries. -- Abstract: Three dimensional (3D) porous C/LiFePO 4 /MWCNTs was synthesized by a hybrid of in situ sol gel strategy and a facile electro-polymerization polyaniline technique and a simultaneous sintering progress. In combined with the 3D hierarchical pore topologies and high electronic conduction facilitating the kinetics of both electron transport and lithium ion diffusion within the particles, the optimized electrodes exhibit an ultrahigh rate capacity, stable charge/discharge cycle ability, and a comparative volume capacity. The synthesized LiFePO 4 composite offers a discharge capacity of 169.6mAhg −1 (nearly to its the theoretical capability 170mAhg −1 ) at the C/10 rate and delivers a good rate performance with a capacity of 141.9mAh g −1 at a high rate of 20 C, and stable charge/discharge cycle ability (>95% capacity retention after 200 charge/discharge cycles).This non-organic facile synthesize avenue can be high desirable to prepare high-power electrode materials

Charge Localization in the Lithium Iron Phosphate Li3Fe2(PO4)3at High Voltages in Lithium-Ion Batteries

DEFF Research Database (Denmark)

Younesi, Reza; Christiansen, Ane Sælland; Loftager, Simon

2015-01-01

Possible changes in the oxidation state of the oxygen ion in the lithium iron phosphate Li3Fe2(PO4)3 at high voltages in lithium-ion (Li-ion) batteries are studied using experimental and computational analysis. Results obtained from synchrotron-based hard X-ray photoelectron spectroscopy...

High performance screen printable lithium-ion battery cathode ink based on C-LiFePO4

International Nuclear Information System (INIS)

Sousa, R.E.; Oliveira, J.; Gören, A.; Miranda, D.; Silva, M.M.; Hilliou, Loic; Costa, C.M.; Lanceros-Mendez, S.

2016-01-01

Highlights: • C-LiFePO 4 paste was been prepared for screen-printing technique. • The inks produced have a Newtonian viscosity of 3 Pa.s for this printing technique. • C-LiFePO 4 inks present a 48.2 mAh.g −1 after 50 cycles at 5C. • This ink is suitable in the development of printed lithium ion batteries. - Abstract: Lithium-ion battery cathodes have been fabricated by screen-printing through the development of C-LiFePO 4 inks. It is shown that shear thinning polymer solutions in N-methyl-2-pyrrolidone (NMP) with Newtonian viscosity above 0.4 Pa s are the best binders for formulating a cathode paste with satisfactory film forming properties. The paste shows an elasticity of the order of 500 Pa and, after shear yielding, shows an apparent viscosity of the order of 3 Pa s for shear rates corresponding to those used during screen-printing. The screen-printed cathode produced with a thickness of 26 μm shows a homogeneous distribution of the active material, conductive additive and polymer binder. The total resistance and diffusion coefficient of the cathode are ∼ 450 Ω and 2.5 × 10 −16 cm 2 s −1 , respectively. The developed cathodes show an initial discharge capacity of 48.2 mAh g −1 at 5C and a discharge value of 39.8 mAh g −1 after 50 cycles. The capacity retention of 83% represents 23% of the theoretical value (charge and/or discharge process in twenty minutes), demonstrating the good performance of the battery. Thus, the developed C-LiFePO 4 based inks allow to fabricate screen-printed cathodes suitable for printed lithium-ion batteries.

Effect of carbon on ion beam mixing of Fe-Ti bilayers

Energy Technology Data Exchange (ETDEWEB)

Hirvonen, J.P.; Nastasi, M.; Lappalainen, R.; Sickafus, K. (Los Alamos National Lab., NM (USA); Helsinki Univ. (Finland). Dept. of Physics; Los Alamos National Lab., NM (USA))

1989-01-01

The influence of implanted carbon on ion beam mixing of a Fe-Ti system was investigated. Carbon was introduced into bilayer samples by implanting {sup 13}C isotopes. The implantation energies were selected to set the mean range of carbon ions in either the iron or titanium layer. The effect of implanted carbon on 400 keV Ar ion mixing in the temperature range from 0 to 300{degree}C was studied using Rutherford backscattering spectroscopy at the energy of 5 MeV. Changes in carbon concentration profiles were probed utilizing the resonance of the nuclear reaction {sup 13}C(p,{gamma}){sup 14}N at the proton energy of 1.748 MeV. The measurements revealed that mixing was not affected by carbon implanted into the titanium layer. However, carbon in the iron layer remarkably retarded mixing at all temperatures investigated. Significant changes in carbon depth distributions were observed only when the sample with implanted carbon in the iron layer was mixed at 300{degree}C. These results are explained in terms of the enhanced mobility of carbon in an evaporated iron film which allows segregation to the interface. At low temperatures, however, vacancy-carbon interaction in iron may have a contribution to the retarded ion beam mixing. 19 refs., 3 figs.

Synthesis and modification of FeVO_4 as novel anode for lithium-ion batteries

International Nuclear Information System (INIS)

Liu, Xiaolin; Cao, Yuancheng; Zheng, Hao; Chen, Xiao; Feng, Chuanqi

2017-01-01

Graphical abstract: The FeVO_4/graphene are synthesized by combining hydrothermal and heat treatment method. It delivered an initial discharge capacity of 1302.3 mAh g"−"1 and remained capacity as 1046.5 mAh g"−"1 after 100 cycles and behaved better electrochemical properties than that of pure FeVO_4. - Highlights: • The FeVO_4 and FeVO_4/graphene are synthesized by combining hydrothermal and heat treatment method. • The FeVO_4/graphene nanocomposite exhibits outstanding electrochemical performance. • FeVO_4/graphene delivered an initial discharge capacity of 1302.3 mAh g"−"1 and remained capacity as 1046.5 mAh g"−"1 after 100 cycles. • The FeVO_4/graphene composite behaved better electrochemical properties than that of pure FeVO_4. - Abstract: FeVO_4 and FeVO_4/graphene nanorods were synthesized successfully by combining a facile hydrothermal and heat treatment method. The samples were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and transmission electron microscopy (TEM) techniques. The content of graphene in FeVO_4/graphene was determined by thermogravimetric analysis (TG). The electrochemical properties of the samples were also investigated by battery testing system. The results showed that the FeVO_4 formed were taken on morphology of nanorods with the length between 0.5 and 1 μm and the diameter in range of 50 to 100 nm. Besides, the size of FeVO_4/graphene was smaller than that of pure FeVO_4. The content of graphene in composite was about 25.0% by weight. The reversible discharge capacities of FeVO_4 and FeVO_4/graphene were 405.2 mAh g"−"1 and 1046.5 mAh g"−"1 separately after 100 cycles at the current density of 100 mAh g"−"1 in the voltage range of 0.01–3 V. The reasons for the FeVO_4/graphene composite to behave outstanding electrochemical properties were also discussed. The FeVO_4/graphene composite can be a novel and promising anode material for lithium ion battery application.

CoFe2O4/carbon nanotube aerogels as high performance anodes for lithium ion batteries

Directory of Open Access Journals (Sweden)

Xin Sun

2017-04-01

Full Text Available High-performance lithium ion batteries (LIBs require electrode material to have an ideal electrode construction which provides fast ion transport, short solid-state ion diffusion, large surface area, and high electric conductivity. Herein, highly porous three-dimensional (3D aerogels composed of cobalt ferrite (CoFe2O4, CFO nanoparticles (NPs and carbon nanotubes (CNTs are prepared using sustainable alginate as the precursor. The key feature of this work is that by using the characteristic egg-box structure of the alginate, metal cations such as Co2+ and Fe3+ can be easily chelated via an ion-exchange process, thus binary CFO are expected to be prepared. In the hybrid aerogels, CFO NPs interconnected by the CNTs are embedded in carbon aerogel matrix, forming the 3D network which can provide high surface area, buffer the volume expansion and offer efficient ion and electron transport pathways for achieving high performance LIBs. The as-prepared hybrid aerogels with the optimum CNT content (20 wt% delivers excellent electrochemical properties, i.e., reversible capacity of 1033 mAh g−1 at 0.1 A g−1 and a high specific capacity of 874 mAh g−1 after 160 cycles at 1 A g−1. This work provides a facile and low cost route to fabricate high performance anodes for LIBs. Keywords: Alginate, Aerogels, Cobalt ferrite, Anode, Lithium-ion battery

Graphene-doped carbon/Fe3O4 porous nanofibers with hierarchical band construction as high-performance anodes for lithium-ion batteries

International Nuclear Information System (INIS)

He, Jianxin; Zhao, Shuyuan; Lian, Yanping; Zhou, Mengjuan; Wang, Lidan; Ding, Bin; Cui, Shizhong

2017-01-01

Highlights: • GN@C/Fe 3 O 4 are synthesized via in-situ electrospinning and thermal treatment. • GN@C/Fe 3 O 4 show unique dark/light banding with a hierarchical porous structure. • Doped graphene induces a uniform distribution of smaller size Fe 3 O 4 nanoparticles. • Doped graphene provides more active sites and accommodate the volume change. • GN@C/Fe 3 O 4 electrode displays a reversible capacity of 872 mAh/g after 100 cycles. - Abstract: Porous graphene-doped carbon/Fe 3 O 4 (GN@C/Fe 3 O 4 ) nanofibers are synthesized via in-situ electrospinning and subsequent thermal treatment for use as lithium-ion battery anode materials. A polyacrylonitrile (PAN)/polymethyl methacrylate (PMMA) solution containing ferric acetylacetone and graphene oxide nanosheets is used as the electrospinning precursor solution. The resulting porous GN@C/Fe 3 O 4 nanofibers show unique dark/light banding and a hierarchical porous structure. These nanofibers have a Brunauer–Emmett–Teller (BET) specific surface area of 323.0 m 2 /g with a total pore volume of 0.337 cm 3 /g, which is significantly greater than that of a sample without graphene and C/Fe 3 O 4 nanofibers. The GN@C/Fe 3 O 4 nanofiber electrode displays a reversible capacity of 872 mAh/g at a current density of 100 mA/g after 100 cycles, excellent cycling stability, and superior rate capability (455 mA/g at 5 A/g). The excellent performance of porous GN@C/Fe 3 O 4 is attributed to the material’s unique structure, including its striped topography, hierarchical porous structure, and inlaid flexible graphene, which not only provides more accessible active sites for lithium-ion insertion and high-efficiency transport pathways for ions and electrons, but also accommodates the volume change associated with lithium insertion/extraction. Moreover, the zero-valent iron and graphene in the porous nanofibers enhance the conductivity of the electrodes.

A single optical sensor with high sensitivity for detection of Fe{sup 3+} and CN{sup −} ions

Energy Technology Data Exchange (ETDEWEB)

Afshani, Jafar [School of Chemistry, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Badiei, Alireza, E-mail: abadiei@khayam.ut.ac.ir [School of Chemistry, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Nanobiomedicine Center of Excellence, Nanoscience and Nanotechnology Research Center, University of Tehran, Tehran (Iran, Islamic Republic of); Jafari, Maryam; Shayesteh, Alireza; Karimi, Mehdi; Lashgari, Negar [School of Chemistry, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Mohammadi Ziarani, Ghodsi [Department of Chemistry, Alzahra University, Tehran (Iran, Islamic Republic of)

2016-11-15

1,2-Bis(2-hydroxymethylphenoxy)ethane was synthesized and characterized by FT-IR and {sup 1}H NMR spectroscopy, and single crystal X-ray diffraction method. The sensing ability of the sensor was studied in the presence of different cations and anions. Following the excitation wavelengths at 275 nm in EtOH/H{sub 2}O (1:9, v/v) and 310 nm in MeCN/H{sub 2}O (1:9, v/v), two distinct emissions at 305 and 356 nm were obtained, respectively. Fe{sup 3+} and CN{sup −} ions were successfully detected in EtOH/H{sub 2}O and MeCN/H{sub 2}O mixtures, respectively. While the fluorescence intensity of the sensor quenched considerably in the presence of Fe{sup 3+} cation at 305 nm, it enhanced in the presence of CN{sup −} anion at 356 nm. Selectivity of the sensor toward these ions was verified in the presence of a variety of common interfering ions. The detection limits of Fe{sup 3+} and CN{sup −} were calculated as 5.4 × 10{sup −9} mol L{sup −1} and 1.9 × 10{sup −8} mol L{sup −1}, respectively which shows the high sensitivity of the sensor toward the target ions. Finally, the interaction of the sensor and CN{sup −} anion was determined by computational studies.

The importance of a Ni correction with ion counter in the double spike analysis of Fe isotope compositions using a 57Fe/58Fe double spike

Science.gov (United States)

Finlayson, V. A.; Konter, J. G.; Ma, L.

2015-12-01

We present a new method capable of measuring iron isotope ratios of igneous materials to high precision by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) using a 57Fe-58Fe double spike. After sample purification, near-baseline signal levels of nickel are still present in the sample solution, acting as an isobaric interference on 58 amu. To correct for the interference, the minor 60Ni isotope is monitored and used to subtract a proportional 58Ni signal from the total 58 amu beam. The 60Ni signal is difficult to precisely measure on the Faraday detector due to Johnson noise occurring at similar magnitude. This noise-dominated signal is subtracted from the total 58 amu beam, and its error amplified during the double spike correction. Placing the 60Ni beam on an ion counter produces a more precise measurement, resulting in a near-threefold improvement in δ56Fe reproducibility, from ±0.145‰ when measured on Faraday to 0.052‰. Faraday detectors quantify the 60Ni signal poorly, and fail to discern the transient 20Ne40Ar interference visible on the ion counter, which is likely responsible for poor reproducibility. Another consideration is instrumental stability (defined herein as drift in peak center mass), which affects high-resolution analyses. Analyses experiencing large drift relative to bracketing standards often yield nonreplicating data. Based on this, we present a quantitative outlier detection method capable of detecting drift-affected data. After outlier rejection, long-term precision on individual runs of our secondary standard improves to ±0.046‰. Averaging 3-4 analyses further improves precision to 0.019‰, allowing distinction between ultramafic minerals.

Exploring hierarchical FeS2/C composite nanotubes arrays as advanced cathode for lithium ion batteries

Science.gov (United States)

Pan, G. X.; Cao, F.; Xia, X. H.; Zhang, Y. J.

2016-11-01

Rational construction of advanced FeS2 cathode is one of research hotspots, and of great importance for developing high-performance lithium ion batteries (LIBs). Herein we report a facile hydrolysis-sulfurization method for fabrication of FeS2/C nanotubes arrays with the help of sacrificial Co2(OH)2CO3 nanowires template and glucose carbonization. Self-supported FeS2/C nanotubes consist of interconnected nanoburrs of 5-20 nm, and show hierarchical porous structure. The FeS2/C nanotubes arrays are demonstrated with enhanced cycling life and noticeable high-rate capability with capacities ranging from 735 mAh g-1 at 0.25 C to 482 mAh g-1 at 1.5 C, superior to those FeS2 counterparts in the literature. The composite nanotubes arrays architecture plays positive roles in the electrochemical enhancement due to combined advantages of large electrode-electrolyte contact area, good strain accommodation, improved electrical conductivity, and enhanced structural stability.

Hierarchical LiFePO4 with a controllable growth of the (010) facet for lithium-ion batteries.

Science.gov (United States)

Guo, Binbin; Ruan, Hongcheng; Zheng, Cheng; Fei, Hailong; Wei, Mingdeng

2013-09-27

Hierarchically structured LiFePO4 was successfully synthesized by ionic liquid solvothermal method. These hierarchically structured LiFePO4 samples were constructed from nanostructured platelets with their (010) facets mainly exposed. To the best of our knowledge, facet control of a hierarchical LiFePO4 crystal has not been reported yet. Based on a series of experimental results, a tentative mechanism for the formation of these hierarchical structures was proposed. After these hierarchically structured LiFePO4 samples were coated with a thin carbon layer and used as cathode materials for lithium-ion batteries, they exhibited excellent high-rate discharge capability and cycling stability. For instance, a capacity of 95% can be maintained for the LiFePO4 sample at a rate as high as 20 C, even after 1000 cycles.

Interconnected α-Fe2O3 nanosheet arrays as high-performance anode materials for lithium-ion batteries

International Nuclear Information System (INIS)

Cai, Dandan; Li, Dongdong; Ding, Liang-Xin; Wang, Suqing; Wang, Haihui

2016-01-01

The electrode materials with structure stability and binder-free are urgently required for improving the electrochemical performance of lithium-ion batteries. In this work, interconnected α-Fe 2 O 3 nanosheet arrays directly grown on Ti foil were fabricated via a facile galvanostatic electrodeposition method followed by thermal treatment. The as-prepared α-Fe 2 O 3 has an open network structure constituted of interconnected nanosheets and can be directly used as integrated electrodes for lithium-ion batteries. The α-Fe 2 O 3 nanosheet arrays exhibit a high reversible capacity of 986.3 mAh g −1 at a current density of 100 mA g −1 . Moreover, a reversible capacity of ca. 425.9 mAh g −1 is achieved even at a superhigh current density of 10 A g −1 , which is higher than the theoretical capacity of commercially used graphite. The excellent performance could be attributed to the efficient electron transport, the large electrode/electrolyte interfaces and the good accommodations for volume expansion from the interconnected nanosheet arrays structure.

Synthesis of three-dimensional rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures using one-pot hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Gao, Guo, E-mail: guogao@sjtu.edu.cn [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Qiang; Cheng, Xin-Bing [Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Sun, Rongjin [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Shapter, Joseph G., E-mail: joe.shapter@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, Bedford Park, Adelaide 5042 (Australia); Yin, Ting [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Cui, Daxiang, E-mail: dxcui@sjtu.edu.cn [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2015-11-15

Rechargeable lithium ion batteries (LIBs) are currently the dominant power source for all sorts of electronic devices due to their low cost and high energy density. The cycling stability of LIBs is significantly compromised due to the broad satellite peak for many anode materials. Herein, we develop a facile hydrothermal process for preparing rare-earth (Er, Tm) ions doped three-dimensional (3D) transition metal oxides/carbon hybrid nanocomposites, namely CNTs-GO-Fe{sub 3}O{sub 4}, CNTs-GO-Fe{sub 3}O{sub 4}-Er and CNTs-GO-Fe{sub 3}O{sub 4}-Tm. The GO sheets and CNTs are interlinked by ultrafine Fe{sub 3}O{sub 4} nanoparticles forming three-dimensional (3D) architectures. When evaluated as anode materials for LIBs, the CNTs-GO-Fe{sub 3}O{sub 4} hybrid composites have a bigger broad satellite peak. As for the CNTs-GO-Fe{sub 3}O{sub 4}-Er and CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites, the broad satellite peak can be completely eliminated. When the current density changes from 5 C back to 0.1 C, the capacity of CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites can recover to 1023.9 mAhg{sup −1}, indicating an acceptable rate capability. EIS tests show that the charge transfer resistance does not change significantly after 500 cycles, demonstrating that the cycling stability of CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites are superior to CNTs-GO-Fe{sub 3}O{sub 4} and CNTs-GO-Fe{sub 3}O{sub 4}-Er hybrid structures. - Graphical abstract: One-pot hydrothermal method for synthesis of rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures as anode materials of LIBs have been reported. - Highlights: • We report the synthesis of rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures. • The hybrid structures can improve the cycling stability of lithium storage. • As for anode materials, the broad satellite peak can be completely eliminated. • When the rate return back to 0.1 C, the capacity can recover to 1023.9 mAhg{sup −1}. • After 500

Microstructure and mechanical properties of FeCrAl alloys under heavy ion irradiations

Science.gov (United States)

Aydogan, E.; Weaver, J. S.; Maloy, S. A.; El-Atwani, O.; Wang, Y. Q.; Mara, N. A.

2018-05-01

FeCrAl ferritic alloys are excellent cladding candidates for accident tolerant fuel systems due to their high resistance to oxidation as a result of formation of a protective Al2O3 scale at high temperatures in steam. In this study, we report the irradiation response of the 10Cr and 13Cr FeCrAl cladding tubes under Fe2+ ion irradiation up to ∼16 dpa at 300 °C. Dislocation loop size, density and characteristics were determined using both two-beam bright field transmission electron microscopy and on-zone scanning transmission electron microscopy techniques. 10Cr (C06M2) tube has a lower dislocation density, larger grain size and a slightly weaker texture compared to the 13Cr (C36M3) tube before irradiation. After irradiation to 0.7 dpa and 16 dpa, the fraction of type sessile dislocations decreases with increasing Cr amount in the alloys. It has been found that there is neither void formation nor α‧ precipitation as a result of ion irradiations in either alloy. Therefore, dislocation loops were determined to be the only irradiation induced defects contributing to the hardening. Nanoindentation testing before the irradiation revealed that the average nanohardness of the C36M3 tube is higher than that of the C06M2 tube. The average nanohardness of irradiated tube samples saturated at 1.6-2.0 GPa hardening for both tubes between ∼3.4 dpa and ∼16 dpa. The hardening calculated based on transmission electron microscopy was found to be consistent with nanohardness measurements.

The Fe Ion Implantation of High Dose on the Ag Substrate for GMRApplications

International Nuclear Information System (INIS)

Sudjatmoko; Tri-Mardji-Atmono; Tjipto-Sujitno

2000-01-01

In this research the implantation of Fe ions on the Ag substrate withsome variation of ion dose and energy as well as annealing temperature havebeen done. The aim of this research was to obtain the magnetic thin filmswhich has a minimum specific resistance and a optimum GMR ratio. On the ionimplantation process the variation of ion dose from 1.5 x 10 17 ions/cm 2 upto 9.0 x 10 17 ions/cm 2 and ion energy from 40 keV to 100 keV. After ionimplantation the samples was annealed on the temperatures of 100 o C, 300 o Cand 500 o C during 30 minutes, respectively. The specific resistance ofsamples were measured by using a four point probe, and the magnetoresistancewas obtained by measuring the specific resistance of samples in the magneticfield. The microstructure of samples was investigated by using SEM and thechanging of the chemical composition was determined by EDAXS. Based on thedata analysis was obtained that the minimum specific resistance was (167 ±3) x 10 -9 Ωm and the optimum GMR ratio was 64.9 % were occurred oncondition of the ion dose of 6.0 x 10 17 ions/cm 2 , the ion energy of 100keV and the annealing temperature of 300 o C. The analysis of chemicalcomposition on the optimum condition was obtained that the content of Feelement was 1.13 % weight. (author)

Self-assembled LiFePO4 nanowires with high rate capability for Li-ion batteries.

Science.gov (United States)

Peng, Lele; Zhao, Yu; Ding, Yu; Yu, Guihua

2014-08-28

Controlling the dimensions in the nanometer scale of olivine-type LiFePO4 has been regarded as one of the most effective strategies to improve its electrochemical performance for Li-ion batteries. In this communication, we demonstrate a novel LiFePO4 nanoarchitecture, which is composed of self-assembled single-crystalline nanowires and exhibits good rate capability with a reversible capacity of ∼110 mA h g(-1) at a current rate of 30 C, and a stable capacity retention of ∼86% after 1000 cycles at a current rate of 10 C.

Critical current densities and flux creep rate in Co-doped BaFe2As2 with columnar defects introduced by heavy-Ion irradiation

International Nuclear Information System (INIS)

Nakajima, Y.; Tsuchiya, Y.; Taen, T.; Yagyuda, H.; Tamegai, T.; Okayasu, S.; Sasase, M.; Kitamura, H.; Murakami, T.

2010-01-01

We report the formation of columnar defects in Co-doped BaFe 2 As 2 single crystals with different heavy-ion irradiations. The formation of columnar defects by 200 MeV Au ion irradiation is confirmed by transmission electron microscopy and their density is about 40% of the irradiation dose. Magneto-optical imaging and bulk magnetization measurements reveal that the critical current density J c is enhanced in the 200 MeV Au and 800 MeV Xe ion irradiated samples while J c is unchanged in the 200 MeV Ni ion irradiated sample. We also find that vortex creep rates are strongly suppressed by the columnar defects. We compare the effect of heavy-ion irradiation into Co-doped BaFe 2 As 2 and cuprate superconductors.

Organophosphonic acid as precursor to prepare LiFePO4/carbon nanocomposites for high-power lithium ion batteries

International Nuclear Information System (INIS)

Chen, Ming; Shao, Leng-Leng; Yang, Hua-Bin; Zhao, Qian-Yong; Yuan, Zhong-Yong

2015-01-01

Graphical abstract: LiFePO4/C nanocomposites were prepared by a quasi-sol–gel method with the use of organophosphonic acid, exhibiting improved electrochemical performance with excellent cycle stability. Display Omitted -- Highlights: •Amino tris(methylene phosphonic acid) is served as a novel precursor for LiFePO 4 /C. •Nano-sized and high-purity LiFePO 4 /C composites are obtained by a quasi-sol–gel route. •Core-shell structured LiFePO 4 /C nanocomposites are fabricated by further introducing sucrose. •Superior electrochemical performance is observed in the organophosphorus-synthesized LiFePO 4 /C. -- Abstract: Amino tris(methylene phosphonic acid) (ATMP) is selected as phosphorus and carbon co-source for the synthesis of uniformly nano-sized LiFePO 4 /C by a quasi-sol–gel method. This strategy using ATMP instead of conventional NH 4 H 2 PO 4 supplies two advantages: firstly, ATMP in situ chelates Li + onto its framework and subsequently binds with FeC 2 O 4 in aqueous solution, forming a molecule-scale homogeneous precursor which can obviously improve the purity of LiFePO 4 . Secondly, the organic carbon contained in ATMP can form uniformly distributed conductive carbon networks among LiFePO 4 particles after calcination, which improves the electrical conductivity. The resultant LiFePO 4 /C with 1.1 wt.% carbon achieves a higher discharge capacity than those of LiFePO 4 and LiFePO 4 /C prepared with inorganic NH 4 H 2 PO 4 . Moreover, core-shell structured LiFePO 4 /C nanocomposites are also fabricated by further introducing sucrose into the synthesis system. The high-quality carbon shell effectively hinders the LiFePO 4 particle growth and aggregation under high-temperature treatment, which further enhances the electrical conductivity and lithium-ion diffusion, resulting in the improved electrochemical performance with excellent cycle stability (the optimum discharge capacity of 158.6 mAh g −1 at 0.1 C and 138.4 mAh g −1 at 2 C). The high

Liquid crystal based optical platform for the detection of Pb2+ ions using NiFe2O4 nanoparticles

Science.gov (United States)

Zehra, Saman; Gul, Iftikhar Hussain; Hussain, Zakir

2018-06-01

A simple, sensitive, selective and real time detection protocol was developed for Pb2+ ions in water using liquid crystals (LCs). In this method, NiFe2O4 nanoparticles were synthesized using chemical co-precipitation method. Crystallite size, morphological, functional groups and magnetization studies were confirmed using X-ray diffraction, Scanning Electron Microscopy, and Fourier transform infrared spectroscopy techniques, respectively. The nanoparticles were mono dispersed with average particle size of 20 ± 2 nm. The surfactant stabilized magnetic nanoparticles were incubated in liquid crystal based sensor system for the detection of Pb+2 ions. The bright to dark transition of LC was observed through optical microscope. When this system was further immersed with a solution containing Pb2+ ions, it caused homeotropic to planar orientation of LC. This interaction is attributed to the presence of abundant hydroxyl groups in such as M-OH, Fe-OH on the surface of spinel ferrites nanoparticles. These groups interact with metal ions at aqueous interface, causing disruption in LCs orientation giving bright texture. This sensor showed higher selectivity towards Pb2+ ions. The detection limit was estimated to be 100 ppb. The cheap and effective protocol reported here should make promising development of LC based sensor for lead ion detection.

Supramolecular Host-Guest System as Ratiometric Fe3+ Ion Sensor Based on Water-Soluble Pillar[5]arene.

Science.gov (United States)

Yao, Qianfang; Lü, Baozhong; Ji, Chendong; Cai, Yang; Yin, Meizhen

2017-10-18

Developing a specific, ratiometric, and reversible detection method for metal ions is significant to guard against the threat of metal-caused environmental pollution and organisms poisoning. Here a supramolecular host-guest system (WP5⊃G) based on water-soluble pillar[5]arene (WP5) and water-soluble quaternized perylene diimide derivative (G) was constructed. Morphological transformation was achieved during the process of adding WP5 into G aqueous solution, and a fluorescence "turn-off" phenomenon was observed which was caused by supramolecular photoinduced electron transfer (PET). Meanwhile, hydrophobic effect and electrostatic interaction played important roles in this supramolecular process, which was confirmed by isothermal titration calorimeter (ITC) and ζ potential experiments. Furthermore, the supramolecular host-guest system could be a "turn-on" fluorescent probe for Fe 3+ ion detection through the process of interdicting supramolecular PET. Moreover, the Fe 3+ ion detection showed specific, ratiometric, and reversible performances with a detection limit of 2.13 × 10 -7 M, which might have great potentials in biological and environmental monitoring.

Conductivity enhancement of ion tracks in tetrahedral amorphous carbon by doping with N, B, Cu and Fe

International Nuclear Information System (INIS)

Krauser, J.; Nix, A.-K.; Gehrke, H.-G.; Hofsäss, H.; Trautmann, C.; Weidinger, A.

2012-01-01

Conducting ion tracks are formed when high-energy heavy ions (e.g. 1 GeV Au) pass through tetrahedral amorphous carbon (ta-C). These nanowires with a diameter of about 8 nm are embedded in the insulating ta-C matrix and of interest for various nanotechnological applications. Usually the overall conductivity of the tracks and the current/voltage characteristics (Ohmic or non-Ohmic) vary strongly from track to track, even when measured on the same sample, indicating that the track formation is neither complete nor homogeneous. To improve the track conductivity, doping of ta-C with N, B, Cu, or Fe is investigated. Beneficial changes in track conductivity after doping compete with a conductivity increase of the surrounding matrix material. Best results are achieved by incorporation of 1 at.% Cu, while for different reasons, the improvement of the tracks remains moderate for N, B, and Fe doping. Conductivity enhancement of the tracks is assumed to develop during the ion track formation process by an increased number of localized states which contribute to the current transport.

Studies of the rare earth-iron interactions in the orthoferrites GdFeO3 and HoFeO3

International Nuclear Information System (INIS)

Sakata, T.; Enomura, A.

1979-01-01

The magnetic behaviour of GdFeO 3 and HoFeO 3 is investigated by means of a Faraday type magnetic balance in a temperature range where rare earth ions are in the paramagnetic state. The results are analyzed in terms of an effective field at a rare earth ion site. Thereby the isotropic exchange field as well as the magnetic dipole field are taken into account. By this means the exchange integral, J/k(K), between an iron ion and a rare earth ion may be estimated to be 0.23 for GdFeO 3 and 0.25 for HoFeO 3 , respectively. (author)

ZnFe2O4-C/LiFePO4-CNT: A Novel High-Power Lithium-Ion Battery with Excellent Cycling Performance.

Science.gov (United States)

Varzi, Alberto; Bresser, Dominic; von Zamory, Jan; Müller, Franziska; Passerini, Stefano

2014-07-15

An innovative and environmentally friendly battery chemistry is proposed for high power applications. A carbon-coated ZnFe 2 O 4 nanoparticle-based anode and a LiFePO 4 -multiwalled carbon nanotube-based cathode, both aqueous processed with Na-carboxymethyl cellulose, are combined, for the first time, in a Li-ion full cell with exceptional electrochemical performance. Such novel battery shows remarkable rate capabilities, delivering 50% of its nominal capacity at currents corresponding to ≈20C (with respect to the limiting cathode). Furthermore, the pre-lithiation of the negative electrode offers the possibility of tuning the cell potential and, therefore, achieving remarkable gravimetric energy and power density values of 202 Wh kg -1 and 3.72 W kg -1 , respectively, in addition to grant a lithium reservoir. The high reversibility of the system enables sustaining more than 10 000 cycles at elevated C-rates (≈10C with respect to the LiFePO 4 cathode), while retaining up to 85% of its initial capacity.

Mechanical properties and plasticity size effect of Fe-6%Cr irradiated by Fe ions and by neutrons

Energy Technology Data Exchange (ETDEWEB)

Hardie, C.D., E-mail: chris.hardie@ukaea.uk [EURATOM/CCFE Association, Culham Centre for Fusion Energy (CCFE), Abingdon, Oxfordshire, OX14 3DB (United Kingdom); Department of Materials, University of Oxford, Oxford, OX1 3PH (United Kingdom); Odette, G.R.; Wu, Y. [UCSB Department of Mechanical Engineering, 2343 Engineering II Building, Santa Barbara, CA 93106-5070 (United States); Akhmadaliev, S. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, D-01328 Dresden (Germany); Roberts, S.G. [EURATOM/CCFE Association, Culham Centre for Fusion Energy (CCFE), Abingdon, Oxfordshire, OX14 3DB (United Kingdom); Department of Materials, University of Oxford, Oxford, OX1 3PH (United Kingdom)

2016-12-15

The mechanical behaviour of Fe6%Cr in the un-irradiated, self-ion irradiated and neutron irradiated conditions was measured and compared. Irradiations were performed to the same dose and at the same temperature but to very different damage rates for both methods. The materials were tested using nanoindentation and micromechanical testing, and compared with microstructural observations from Transmission Electron Microscopy (TEM) and Atom Probe Tomography (APT) reported elsewhere. Irradiated and un-irradiated micro-cantilevers with a wide range of dimensions were used to study the interrelationships between irradiation hardening and size effects in small-scale plasticity. TEM and APT results identified that the dislocation loop densities were ∼2.9 × 10{sup 22}m{sup −3} for the neutron irradiated material and only 1.4 × 10{sup 22}m{sup −3} for the ion irradiated material. Cr segregation to loops was only found for the neutron-irradiated material. The nanoindentation hardness increase due to neutron irradiation was 3 GPa and that due to ion irradiation 1 GPa. The differences between the effects of the two irradiation types are discussed, taking into account inconsistencies in damage calculations, and the differences in PKA spectra, dose rate and transmutation products for the two irradiation types.

Critical process temperatures for resistive InGaAsP/InP heterostructures heavily implanted by Fe or Ga ions

Energy Technology Data Exchange (ETDEWEB)

Fekecs, André [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Chicoine, Martin [Département de Physique, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Ilahi, Bouraoui [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); SpringThorpe, Anthony J. [Canadian Photonics Fabrication Centre, National Research Council, Ottawa, ON K1A 0R6 (Canada); Schiettekatte, François [Département de Physique, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Morris, Denis [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); and others

2015-09-15

Highlights: • InGaAsP/InP alloys were processed by MeV ion implantation and rapid thermal annealing. • X-ray diffraction and Hall measurement results are compared for several process conditions. • Amorphous layers formed at low implantation temperature. • Dynamic annealing prevented amorphization at implantation above room temperature. • After annealing near 500 °C, sheet resistivities of 10{sup 7} Ω/sq were obtained with low temperature Fe implantation. - Abstract: We report on critical ion implantation and rapid thermal annealing (RTA) process temperatures that produce resistive Fe- or Ga-implanted InGaAsP/InP heterostructures. Two InGaAsP/InP heterostructure compositions, with band gap wavelengths of 1.3 μm and 1.57 μm, were processed by ion implantation sequences done at multiple MeV energies and high fluence (10{sup 15} cm{sup −2}). The optimization of the fabrication process was closely related to the implantation temperature which influences the type of implant-induced defect structures. With hot implantation temperatures, at 373 K and 473 K, X-ray diffraction (XRD) revealed that dynamic defect annealing was strong and prevented the amorphization of the InGaAsP layers. These hot-implanted layers were less resistive and RTA could not optimize them systematically in favor of high resistivity. With cold implantation temperatures, at 83 K and even at 300 K, dynamic annealing was minimized. Damage clusters could form and accumulate to produce resistive amorphous-like structures. After recrystallization by RTA, polycrystalline signatures were found on every low-temperature Fe- and Ga-implanted structures. For both ion species, electrical parameters evolved similarly against annealing temperatures, and resistive structures were produced near 500 °C. However, better isolation was obtained with Fe implantation. Differences in sheet resistivities between the two alloy compositions were less than band gap-related effects. These observations, related

SAXS investigation of latent track structure in HDPE irradiated with high energy Fe ions

Energy Technology Data Exchange (ETDEWEB)

Hai, Yang; Huang, Can [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ma, Mingwang [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Institute of Electronic Engineering, CAEP, Mianyang 621900 (China); Liu, Qi; Wang, Yuzhu; Liu, Yi; Tian, Feng; Lin, Jun [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhu, Zhiyong, E-mail: zhuzhiyong@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2015-08-01

Semi-crystalline high density polyethylene (HDPE) samples were irradiated with 1.157 GeV {sup 56}Fe ion beams to fluences ranging from 1 × 10{sup 11} to 6 × 10{sup 12} ions/cm{sup 2}. The radiation induced changes in nano/microstructure were investigated with small angle X-ray scattering (SAXS) technique. The scattering contributions from HDPE matrix and ion tracks are successfully separated and analyzed through tilted SAXS measurements with respect to the X-ray beam direction. Lorentz correction, one-dimensional correlation function calculation, fractal nature analysis of the isotropic scattering pattern reveal that HDPE long period polymeric structures are damaged and new materials, possibly clusters of carbon-rich materials, are formed inside the ion tracks. Least square curve fitting of the scattering contribution from the ion track reveals that the track is composed of a core of about 5.3 nm in radius, characterized by a significant density deficit compared to the virgin HDPE, surrounded by a shell of about 4.3 nm in thickness with less density reduction.

Ultra-small Fe3O4 nanocrystals decorated on 2D graphene nanosheets with excellent cycling stability as anode materials for lithium ion batteries

International Nuclear Information System (INIS)

Ren, Manman; Yang, Mingzhi; Liu, Weiliang; Li, Mei; Su, Liwei; Qiao, Congde; Wu, Xianbin; Ma, Houyi

2016-01-01

Graphical abstract: Ultra-small Fe 3 O 4 nanocrystals decorated on 2D graphene nanosheets with excellent cycling stability as anode materials for lithium ion batteries Manman Ren, Mingzhi Yang, Weiliang Liu, Mei Li, Liwei Su, Congde Qiao, Xianbin Wu, Houyi Ma Ultra-small Fe 3 O 4 nanocrystals/graphene nanosheets composites demonstrate excellent long-term cycling stability at high-rate. - Abstract: Ultra-small Fe 3 O 4 nanocrystals (NCs)/garphene nanosheets (GNSs) composites have been synthesized through a facile gel-like film (GF) assisted method in this work. Fe 3 O 4 NCs with particle size ∼10 nm homogeneously dispersed on 2D GNSs. Profiting from the ultra-small Fe 3 O 4 NCs and GNSs, the composites demonstrate superior long-term and high-rate performance as anode materials for lithium ion batteries. Even at the current density of 5 A g −1 , the reversible capacity still maintains 323.4 mAh g −1 after 700 cycles. This work might enlighten us on exploring preferable strategies to develop advanced metal oxides NCs/GNSs composites anode materials for lithium ion batteries or other energy storage devices.

Development of high-polarization Fe/Ge neutron polarizing supermirror: Possibility of fine-tuning of scattering length density in ion beam sputtering

Science.gov (United States)

Maruyama, R.; Yamazaki, D.; Akutsu, K.; Hanashima, T.; Miyata, N.; Aoki, H.; Takeda, M.; Soyama, K.

2018-04-01

The multilayer structure of Fe/Si and Fe/Ge systems fabricated by ion beam sputtering (IBS) was investigated using X-ray and polarized neutron reflectivity measurements and scanning transmission electron microscopy with energy-dispersive X-ray analysis. The obtained result revealed that the incorporation of sputtering gas particles (Ar) in the Ge layer gives rise to a marked reduction in the neutron scattering length density (SLD) and contributes to the SLD contrast between the Fe and Ge layers almost vanishing for spin-down neutrons. Bundesmann et al. (2015) have shown that the implantation of primary Ar ions backscattered at the target is responsible for the incorporation of Ar particles and that the fraction increases with increasing ion incidence angle and increasing polar emission angle. This leads to a possibility of fine-tuning of the SLD for the IBS, which is required to realize a high polarization efficiency of a neutron polarizing supermirror. Fe/Ge polarizing supermirror with m = 5 fabricated under the same condition showed a spin-up reflectivity of 0.70 at the critical momentum transfer. The polarization was higher than 0.985 for the qz range where the correction for the polarization inefficiencies of the beamline works properly. The result of the polarized neutron reflectivity measurement suggests that the "magnetically-dead" layers formed at both sides of the Fe layer, together with the SLD contrast, play a critical role in determining the polarization performance of a polarizing supermirror.

[Stabilization of Cadmium Contaminated Soils by Ferric Ion Modified Attapulgite (Fe/ATP)--Characterizations and Stabilization Mechanism].

Science.gov (United States)

Rong, Yang; Li, Rong-bo; Zhou, Yong-li; Chen, Jing; Wang, Lin-ling; Lu, Xiao-hua

2015-08-01

Ferric ion modified attapulgite (Fe/ATP) was prepared by impregnation and its structure and morphology were characterized. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effect of Cadmium( Cd) stabilization in soil with the addition of attapulgite (ATP) and Fe/ATP. The stabilization mechanism of Cd was further elucidated by comparing the morphologies and structure of ATP and Fe/ATP before and after Cd adsorption. Fe/ATP exhibited much better adsorption capacity than ATP, suggesting different adsorption mechanisms occurred between ATP and Fe/ATP. The leaching concentrations of Cd in soil decreased by 45% and 91% respectively, with the addition of wt. 20% ATP and Fe/ATP. The former was attributed to the interaction between Cd2 and --OH groups by chemical binding to form inner-sphere complexes in ATP and the attachment between Cd2+ and the defect sites in ATP framework. Whereas Cd stabilization with Fe/ATP was resulted from the fact that the active centers (--OH bonds or O- sites) on ATP could react with Fe3+ giving Fe--O--Cd-- bridges, which helped stabilize Cd in surface soil. What'more, the ferric oxides and metal hydroxides on the surface of ATP could interact with Cd, probably by the formation of cadmium ferrite. In conclusion, Fe/ATP, which can be easily prepared, holds promise as a potential low-cost and environmental friendly stabilizing agent for remediation of soil contaminated with heavy metals.

On the role of Fe ions on magnetic properties of doped TiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tolea, F.; Grecu, M. N., E-mail: mgrecu@infim.ro; Kuncser, V.; Constantinescu, S. Gr.; Ghica, D. [National Institute of Materials Physics (NIMP), Mǎgurele-Ilfov 077125 (Romania)

2015-04-06

The role of iron doping on magnetic properties of hydrothermal anatase TiO{sub 2}:{sup 57}Fe (0–1 at. %) nanoparticles is investigated by combining superconducting quantum interference device magnetometry with Mössbauer and electron paramagnetic resonance techniques. The results on both as-prepared and thermally treated samples in reduced air atmosphere reveal complexity of magnetic interactions, in connection to certain iron ion electron configurations and defects (oxygen vacancies, F-center, and Ti{sup 3+} ions). The distribution of iron ions is predominantly at nanoparticle surface layers. Formation of weak ferromagnetic domains up to 380 K is mainly related to defects, supporting the bound magnetic polaron model.

Inverse spinel ZnFe2O4 nanoparticles synthesized by ion implantation and post-annealing: An investigation using X-ray spectroscopy and magneto-transport

International Nuclear Information System (INIS)

Zhou Shengqiang; Potzger, K.; Buerger, D.; Kuepper, K.; Helm, M.; Fassbender, J.; Schmidt, H.

2009-01-01

Noncrystalline ZnFe 2 O 4 has been investigated intensively due to the drastic difference in cation distribution compared with bulk materials. We previously synthesized ZnFe 2 O 4 nanoparticles by ion implantation and post-annealing [S. Zhou, K. Potzger, H. Reuther, G. Talut, F. Eichhorn, J. von Borany, W. Skorupa, M. Helm, J. Fassbender, J. Phys. D - Appl. Phys. 40 (2007) 964]. These ZnFe 2 O 4 nanocrystals are crystallographically oriented inside the ZnO matrix and show a hysteretic behavior upon magnetization reversal at 5 K. Their magnetic properties are explained by assuming that Fe 3+ ions partially occupy tetrahedral sites. In this paper an X-ray spectroscopic and magneto-transport investigation on ZnFe 2 O 4 nanocrystals in a ZnO matrix will be presented. The occupation of Fe 3+ at tetrahedral sites has been directly proved. A positive magnetoresistance (MR) effect is observed and is attributed to ordinary MR.

Fe{sub 3}O{sub 4} nanoparticles-wrapped carbon nanofibers as high-performance anode for lithium-ion battery

Energy Technology Data Exchange (ETDEWEB)

Jiang, Fei; Zhao, Saihua; Guo, Jinxin; Su, Qingmei; Zhang, Jun; Du, Gaohui, E-mail: gaohuidu@zjnu.edu.cn [Zhejiang Normal University, Institute of Physical Chemistry (China)

2015-08-15

One-dimensional hierarchical nanostructures composed of Fe{sub 3}O{sub 4} nanoparticles and carbon nanofibers (CNFs) have been successfully synthesized through a facile solvothermal method followed by a simple thermal annealing treatment. X-ray diffraction and electron microscopy reveal that Fe{sub 3}O{sub 4} nanoparticles with a size of 80–100 nm are uniformly dispersed on CNFs. The Fe{sub 3}O{sub 4}/CNFs nanocomposites show an enhanced reversible capacity and excellent rate performance as anode for Li-ion battery. The reversible capacity of the nanocomposites retains 684 mAh g{sup −1} after 55 cycles at 100 mA g{sup −1}. Even when cycled at various rate (100, 200, 500, 1000, and 2000 mA g{sup −1}) for 50 cycles, the capacity can recover to 757 mAh g{sup −1} at the current of 100 mA g{sup −1}. The enhanced electrochemical performances are attributed to the characteristics of interconnected one-dimensional nanostructures that provide three-dimensional networks for Li-ion diffusion and electron transfer, and can further accommodate the volumetric change of Fe{sub 3}O{sub 4} nanoparticles during charge–discharge cycling.

Electrospun LiFePO₄/C Composite Fiber Membrane as a Binder-Free, Self-Standing Cathode for Power Lithium-Ion Battery.

Science.gov (United States)

Chen, Li-Li; Shen, Xiang-Qian; Jing, Mao-Xiang; Zhu, Sheng-Wen; Pi, Zhi-Chao; Li, Jing-Quan; Zhai, Hong-Ai; Xiao, Ke-Song

2018-07-01

A LiFePO4/C composite fiber membrane was fabricated by the electrospinning method and subsequent thermal treatment. The thermal decomposition process was analyzed by TG/DSC, the morphology, microstructure and composition were studied using SEM, TEM, XRD, Raman, respectively. The results indicated that the prepared LiFePO4/C composite fibers were composed of nanosized LiFePO4 crystals and amorphous carbon coatings, which formed a three dimensional (3D) long-range networks, greatly enhanced the electronic conductivity of LiFePO4 electrode up to 3.59× 10-2 S · cm-2. The 3D LiFePO4/C fiber membrane could be directly used as a binder-free, self-standing cathode for lithium-ion battery, and exhibited an improved capacity and rate performance. The LiFePO4/C composite electrode delivered a discharge capacity of 116 mAh·g-1, 109 mAh·g-1, 103 mAh·g-1, 91 mAh·g-1, 80 mAh·g-1 at 0.1 C, 0.5 C, 1 C, 3 C, 5 C, respectively. And a stable cycling performance was also achieved that the specific capacity could retain 75 mA·g-1 after 500 cycles at 5 C. Therefore, this LiFePO4/C composite fiber membrane was promising to be used as a cathode for power lithium ion battery.

NdFeB alloy as a magnetic electrode material for lithium-ion batteries

International Nuclear Information System (INIS)

Zhang, J.; Shui, J.L.; Zhang, S.L.; Wei, X.; Xiang, Y.J.; Xie, S.; Zhu, C.F.; Chen, C.H.

2005-01-01

The search for a reliable indicator of state of charge and even the remaining energy of a lithium-ion cell is of great importance for various applications. This study was an exploratory effort to use magnetic susceptibility as the indicator. In this work, for the first time the change of ac susceptibility of cells was in situ monitored during charge-discharge process. A strong permanent magnetic material, NdFeB alloy, was investigated as an anode material for rechargeable lithium batteries. Both original and partially oxidized NdFeB powders were made into electrodes. Structural characterization was performed on the NdFeB electrodes by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. An alloy (core)-oxide (shell) structure was found for those partially oxidized samples. The electrochemical cycling of cells made of the NdFeB electrodes against lithium was measured. The first lithium intercalation capacity of a treated NdFeB can be up to about 831 mAh/g, while a rather reversible capacity of up to 352 mAh/g can be obtained. With a specially designed cell, we were able to monitor in situ the change of relative ac susceptibility during charge and/or discharge steps. A clearly monotonous relationship is found between the ac susceptibility of a cell and its depth-of-discharge (DOD). A mechanism based on skin effect and eddy current change is proposed to explain this susceptibility versus DOD relationship

NdFeB alloy as a magnetic electrode material for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Zhang, J. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Shui, J.L. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Zhang, S.L. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Wei, X. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Xiang, Y.J. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Xie, S. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Zhu, C.F. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Chen, C.H. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China)]. E-mail: cchchen@ustc.edu.cn

2005-04-05

The search for a reliable indicator of state of charge and even the remaining energy of a lithium-ion cell is of great importance for various applications. This study was an exploratory effort to use magnetic susceptibility as the indicator. In this work, for the first time the change of ac susceptibility of cells was in situ monitored during charge-discharge process. A strong permanent magnetic material, NdFeB alloy, was investigated as an anode material for rechargeable lithium batteries. Both original and partially oxidized NdFeB powders were made into electrodes. Structural characterization was performed on the NdFeB electrodes by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. An alloy (core)-oxide (shell) structure was found for those partially oxidized samples. The electrochemical cycling of cells made of the NdFeB electrodes against lithium was measured. The first lithium intercalation capacity of a treated NdFeB can be up to about 831 mAh/g, while a rather reversible capacity of up to 352 mAh/g can be obtained. With a specially designed cell, we were able to monitor in situ the change of relative ac susceptibility during charge and/or discharge steps. A clearly monotonous relationship is found between the ac susceptibility of a cell and its depth-of-discharge (DOD). A mechanism based on skin effect and eddy current change is proposed to explain this susceptibility versus DOD relationship.

Glass formation of the Fe-Hf system studied by thermodynamic calculation and ion beam mixing

International Nuclear Information System (INIS)

Wang, T.L.; Wang, W.C.; Li, J.H.; Liu, B.X.

2010-01-01

For the Fe-Hf system characterized by a negative heat of formation, the glass-forming range/ability (GFR/GFA) was studied by thermodynamic calculation based on Miedema's model and Alonso's method. It was found that amorphous phase could be formed in a composition range of 24-86 atom% Hf and that alloy with composition of Fe 58 Hf 42 has the best GFA in the system. Experimentally, ion beam mixing was carried out to synthesize amorphous alloys in the Fe-Hf system. It turned out that in the samples with overall compositions located in the calculated GFR, amorphous phases were indeed obtained, whereas no amorphous phase was obtained if the overall compositions were located outside of the predicted region favoring for amorphous alloy formation, showing a good agreement between the experimental results and the thermodynamic calculation.

Research by Moessbauer and infrared spectroscopy of films of polyacrylonitrile doped with FeCl2 and FeCl3

International Nuclear Information System (INIS)

Santos, Vadilson M. dos; Silva Filho, Eloi A. da; Nunes Filho, Evaristo

2009-01-01

The heating effect on films of polyacrylonitrile and doping of the ions Fe(II) and Fe (III) may reveal important aspects of the use of this polymer in the search for new materials. This paper was done the doping of the films of PAN with ions Fe(II) and Fe (III), with thermo heating is range of 60 a 90 deg C e de 90 a 170 deg C through the alkaline and acid hydrolysis of the CN groups used spectroscopy of FTIR and Moessbauer techniques to evaluate the structural changes results of doping process this polymer. The results showed that the FTIR spectral have a strong interaction of the ions Fe(II) and Fe (III) with PAN and confirmed by Moessbauer data. (author)

Synthesis and electrochemical characterization of mesoporous Li2FeSiO4/C composite cathode material for Li-ion batteries

Science.gov (United States)

Kumar, Ajay; Jayakumar, O. D.; Bazzi, Khadije; Nazri, Gholam-Abbas; Naik, Vaman M.; Naik, Ratna

2015-03-01

Lithium iron silicate (Li2FeSiO4) has the potential as cathode for Li ion batteries due to its high theoretical capacity (~ 330 mAh/g) and improved safety. The application of Li2FeSiO4 as cathode material has been challenged by its poor electronic conductivity and slow lithium ion diffusion in the solid phase. In order to solve these problems, we have synthesized mesoporous Li2FeSiO4/C composites by sol-gel method using the tri-block copolymer (P123) as carbon source. The phase purity and morphology of the composite materials were characterized by x-ray diffraction, SEM and TEM. The XRD pattern confirmed the formation of ~ 12 nm size Li2FeSiO4 crystallites in composites annealed at 600 °C for 6 h under argon atmosphere. The electrochemical properties are measured using the composite material as positive electrode in a standard coin cell configuration with lithium as the active anode and the cells were tested using AC impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge cycling. The Li2FeSiO4/C composites showed a discharge capacity of ~ 240 mAh/g at a rate of C/30 at room temperature. The effect of different annealing temperature and synthesis time on the electrochemical performance of Li2FeSiO4/C will be presented.

Glass forming ability of the Fe-Zr-Cu system studied by thermodynamic calculation and ion beam mixing

International Nuclear Information System (INIS)

Wang, T.L.; Liu, B.X.

2009-01-01

The glass forming ability/range (GFA/GFR) of the Fe-Zr-Cu system was studied by thermodynamic calculation based on Miedema's model and Alonso's method. It is found that when the atomic concentration of Zr is between 34% and 56%, no matter what the atomic concentrations of Fe and Cu are, amorphous phase could be obtained, thus the atomic mismatch playing a dominating role in influencing the GFA. While the atomic concentration of Zr is out of the above range, the GFA is highly influenced by the immiscibility between Fe and Cu. Experimentally, ion beam mixing was carried out to synthesize amorphous alloys in the Fe-Zr-Cu system. It turned out that in the samples with overall compositions of Fe 26 Zr 36 Cu 38 , Fe 52 Zr 27 Cu 21 and Fe 21 Zr 60 Cu 19 , which are located in or at the edge of the calculated GFR, amorphous phases were indeed obtained, whereas no amorphous phase was obtained if the overall compositions were located outside of the predicted region favoring for amorphous alloy formation, showing a good agreement between the experimental results and the thermodynamic calculation.

Interaction between solute atoms and radiation defects in Fe-Ni-Si and Fe-Mn-Si alloys under irradiation with proton ions at low-temperature

Energy Technology Data Exchange (ETDEWEB)

Murakami, Kenta, E-mail: murakami@tokai.t.u-tokyo.ac.jp [Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata-Shirane, Tokai-mura, Ibaraki, 319-1188 (Japan); Iwai, Takeo, E-mail: iwai@med.id.yamagata-u.ac.jp [Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, Yamagata-shi, 990-9585 (Japan); Abe, Hiroaki [Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata-Shirane, Tokai-mura, Ibaraki, 319-1188 (Japan); Sekimura, Naoto, E-mail: sekimura@n.t.u-tokyo.ac.jp [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1, Tokyo, Hongo, Bunkyo, 113-8656 (Japan)

2016-12-15

Isochronal annealing followed by residual resistivity measurements at 12 K was performed in Fe-0.6Ni-0.6Si and Fe-1.5Mn-0.6Si alloys irradiated with 1 MeV proton ions below 70 K, and recovery stages were compared with those of Fe–0.6Ni and Fe–1.5Mn. The effects of silicon addition in the Fe-Ni alloy was observed as the appearance of a new recovery stage at 282–372 K, presumably corresponding to clustering of solute atoms in matrix, and as a change in mixed dumbbell migration at 122–142 K. Silicon addition mitigated the manganese effect in Fe–Mn alloy that is obstructing the recovery of radiation defects. Reduction of resistivity in Fe-Mn-Si alloy also suggested formation of small solute atom clusters.

Solvothermal synthesis of monodisperse LiFePO4 micro hollow spheres as high performance cathode material for lithium ion batteries.

Science.gov (United States)

Yang, Shiliu; Hu, Mingjun; Xi, Liujiang; Ma, Ruguang; Dong, Yucheng; Chung, C Y

2013-09-25

A microspherical, hollow LiFePO4 (LFP) cathode material with polycrystal structure was simply synthesized by a solvothermal method using spherical Li3PO4 as the self-sacrificed template and FeCl2·4H2O as the Fe(2+) source. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the LFP micro hollow spheres have a quite uniform size of ~1 μm consisting of aggregated nanoparticles. The influences of solvent and Fe(2+) source on the phase and morphology of the final product were chiefly investigated, and a direct ion exchange reaction between spherical Li3PO4 templates and Fe(2+) ions was firstly proposed on the basis of the X-ray powder diffraction (XRD) transformation of the products. The LFP nanoparticles in the micro hollow spheres could finely coat a uniform carbon layer ~3.5 nm by a glucose solution impregnating-drying-sintering process. The electrochemical measurements show that the carbon coated LFP materials could exhibit high charge-discharge capacities of 158, 144, 125, 101, and even 72 mAh g(-1) at 0.1, 1, 5, 20, and 50 C, respectively. It could also maintain 80% of the initial discharge capacity after cycling for 2000 times at 20 C.

Metallic oxide nano-clusters synthesis by ion implantation in high purity Fe10Cr alloy

International Nuclear Information System (INIS)

Zheng, Ce

2015-01-01

ODS (Oxide Dispersed Strengthened) steels, which are reinforced with metal dispersions of nano-oxides (based on Y, Ti and O elements), are promising materials for future nuclear reactors. The detailed understanding of the mechanisms involved in the precipitation of these nano-oxides would improve manufacturing and mechanical properties of these ODS steels, with a strong economic impact for their industrialization. To experimentally study these mechanisms, an analytical approach by ion implantation is used, to control various parameters of synthesis of these precipitates as the temperature and concentration. This study demonstrated the feasibility of this method and concerned the behaviour of alloys models (based on aluminium oxide) under thermal annealing. High purity Fe-10Cr alloys were implanted with Al and O ions at room temperature. Transmission electron microscopy observations showed that the nano-oxides appear in the Fe-10Cr matrix upon ion implantation at room temperature without subsequent annealing. The mobility of implanted elements is caused by the defects created during ion implantation, allowing the nucleation of these nanoparticles, of a few nm in diameter. These nanoparticles are composed of aluminium and oxygen, and also chromium. The high-resolution experiments show that their crystallographic structure is that of a non-equilibrium compound of aluminium oxide (cubic γ-Al 2 O 3 type). The heat treatment performed after implantation induces the growth of the nano-sized oxides, and a phase change that tends to balance to the equilibrium structure (hexagonal α-Al 2 O 3 type). These results on model alloys are fully applicable to industrial materials: indeed ion implantation reproduces the conditions of milling and heat treatments are at equivalent temperatures to those of thermo-mechanical treatments. A mechanism involving the precipitation of nano-oxide dispersed in ODS alloys is proposed in this manuscript based on the obtained experimental results

Synthesis and magnetic properties of CoFe2O4 spinel ferrite nanoparticles doped with lanthanide ions

International Nuclear Information System (INIS)

Kahn, Myrtil L.; Zhang, Z. John

2001-01-01

Lanthanide ions have been doped into cobalt spinel ferrites using an oil-in-water micellar method to form CoLn 0.12 Fe 1.88 O 4 nanoparticles with Ln=Ce, Sm, Eu, Gd, Dy, or Er. Doping with lanthanide ions (Ln III ) modulates the magnetic properties of cobalt spinel ferrite nanoparticles. In particular cases of Gd 3+ or Dy 3+ ions, a dramatic increase in the blocking temperature and coercivity is observed. Indeed, the introduction of only 4% of Gd 3+ ions increases the blocking temperature ∼100 K and the coercivity 60%. Initial studies on the magnetic properties of these doped nanoparticles clearly demonstrate that the relationship between the modulation of magnetic properties and the nature of doped Ln III ions is interesting but very complex. [copyright] 2001 American Institute of Physics

Liquid crystal based optical platform for the detection of Pb2+ ions using NiFe2O4 nanoparticles

Directory of Open Access Journals (Sweden)

Saman Zehra

2018-06-01

Full Text Available A simple, sensitive, selective and real time detection protocol was developed for Pb2+ ions in water using liquid crystals (LCs. In this method, NiFe2O4 nanoparticles were synthesized using chemical co-precipitation method. Crystallite size, morphological, functional groups and magnetization studies were confirmed using X-ray diffraction, Scanning Electron Microscopy, and Fourier transform infrared spectroscopy techniques, respectively. The nanoparticles were mono dispersed with average particle size of 20 ± 2 nm. The surfactant stabilized magnetic nanoparticles were incubated in liquid crystal based sensor system for the detection of Pb+2 ions. The bright to dark transition of LC was observed through optical microscope. When this system was further immersed with a solution containing Pb2+ ions, it caused homeotropic to planar orientation of LC. This interaction is attributed to the presence of abundant hydroxyl groups in such as M-OH, Fe-OH on the surface of spinel ferrites nanoparticles. These groups interact with metal ions at aqueous interface, causing disruption in LCs orientation giving bright texture. This sensor showed higher selectivity towards Pb2+ ions. The detection limit was estimated to be 100 ppb. The cheap and effective protocol reported here should make promising development of LC based sensor for lead ion detection. Keywords: Chemical co-precipitation method, Fourier transform infrared spectroscopy, Liquid crystals, Nanoparticles, Sensor, X-ray diffraction

Freeze-drying synthesis of three-dimensional porous LiFePO4 modified with well-dispersed nitrogen-doped carbon nanotubes for high-performance lithium-ion batteries

International Nuclear Information System (INIS)

Tu, Xiaofeng; Zhou, Yingke; Song, Yijie

2017-01-01

Highlights: • Three-dimensional porous LiFePO 4 /N-CNTs is synthesized by a freeze-drying method. • The N-CNTs conductive network enhances the electron transport within the LiFePO 4 electrode. • The continuous pores accelerate the diffusion of lithium ions. • LiFePO 4 /N-CNTs demonstrates an excellent electrochemical Li-insertion performance. - Abstract: The three-dimensional porous LiFePO 4 modified with uniformly dispersed nitrogen-doped carbon nanotubes has been successfully prepared by a freeze-drying method. The morphology and structure of the porous composites are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performances are evaluated using the constant current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The nitrogen-doped carbon nanotubes are uniformly dispersed inside the porous LiFePO 4 to construct a superior three-dimensional conductive network, which remarkably increases the electronic conductivity and accelerates the diffusion of lithium ion. The porous composite displays high specific capacity, good rate capability and excellent cycling stability, rendering it a promising positive electrode material for high-performance lithium-ion batteries.

The catalytic ozonization of model lignin compounds in the presence of Fe(III) ions

Science.gov (United States)

Ben'ko, E. M.; Mukovnya, A. V.; Lunin, V. V.

2007-05-01

The ozonization of several model lignin compounds (guaiacol, 2,6-dimethoxyphenol, phenol, and vanillin) was studied in acid media in the presence of iron(III) ions. It was found that Fe3+ did not influence the initial rate of the reactions between model phenols and ozone but accelerated the oxidation of intermediate ozonolysis products. The metal concentration dependences of the total ozone consumption and effective rate constants of catalytic reaction stages were determined. Data on reactions in the presence of oxalic acid as a competing chelate ligand showed that complex formation with Fe3+ was the principal factor that accelerated the ozonolysis of model phenols at the stage of the oxidation of carboxylic dibasic acids and C2 aldehydes formed as intermediate products.

UV and X-ray spectral lines of Be-like Fe ion for plasma diagnostics

International Nuclear Information System (INIS)

Murakami, Izumi; Kato, Takako; Dubau, J.

1996-04-01

We have calculated X-ray and UV spectra of the Be-like Fe (FeXXIII) ion using collisional-radiative model including all fine-structure transitions among the 2s 2 , 2s2p, 2p 2 , 2snl, and 2pnl levels where n = 3 and 4, adopting data for the collision strengths by Zhang and Sampson (1992) and by Sampson, Goett, and Clark (1984). Some line intensity ratios can be used for the temperature diagnostic. We show 5 ratios in UV region and 9 ratios in X-ray region as functions of electron temperature and density at 0.3keV e e = 1-10 25 cm -3 . The effect of cascade in these line ratios is discussed. (author)

High-rate and ultralong cycle-life LiFePO_4 nanocrystals coated by boron-doped carbon as positive electrode for lithium-ion batteries

International Nuclear Information System (INIS)

Feng, Jinpeng; Wang, Youlan

2016-01-01

Highlights: • B-doped carbon decorated LiFePO_4 has been fabricated for the first time. • The LiFePO_4@B-CdisplaysimprovedbatteryperformancecomparedtoLiFePO_4@C. • The LiFePO_4@B-C is good candidate for high-performance lithium-ion batteries. - Abstract: An evolutionary modification approach, boron-doped carbon coating, has been used to improve the electrochemical performances of positive electrodes for lithium-ion batteries, and demonstrates apparent and significant modification effects. In this study, the boron-doped carbon coating is firstly adopted and used to decorate the performance of LiFePO_4. The obtained composite exhibits a unique core-shell structure with an average diameter of 140 nm and a 4 nm thick boron-doped carbon shell that uniformly encapsulates the core. Owing to the boron element which could induce high amount of defects in the carbon, the electronic conductivity of LiFePO_4 is greatly ameliorated. Thus, the boron-doped composite shows superior rate capability and cycle stability than the undoped sample. For instance, the reversible specific capacity of LiFePO_4@B_0_._4-C can reach 164.1 mAh g"−"1 at 0.1C, which is approximately 96.5% of the theoretical capacity (170 mAh g"−"1). Even at high rate of 10C, it still shows a high specific capacity of 126.8 mAh g"−"1 and can be maintained at 124.5 mAh g"−"1 after 100 cycles with capacity retention ratio of about 98.2%. This outstanding Li-storage property enable the present design strategy to open up the possibility of fabricating the LiFePO_4@B-C composite for high-performance lithium-ion batteries.

Carbonized polydopamine coated single-crystalline NiFe2O4 nanooctahedrons with enhanced electrochemical performance as anode materials in a lithium ion battery

International Nuclear Information System (INIS)

Liu, Xinxin; Zhang, Tong; Qu, Yue; Tian, Ge; Yue, Huijuan; Zhang, Dong; Feng, Shouhua

2017-01-01

Graphical abstract: NiFe 2 O 4 @ NCweresuccessfullyfabricatedviaasubsequentcarbonizationofpolydopamine.(*) A nanocomposite containing 20% mass fraction of dopamine exhibited enhanced lithium ion battery performance with high reversible cycle capacity and good rate retention performance. - Highlights: • NiFe 2 O 4 nanooctahedrons were synthesized by a facile hydrothermal process. • A phase formation mechanism was studied by time-dependent experiments. • NiFe 2 O 4 with N-doped carbon shell was fabricated via carbonization of polydopamine. • NiFe 2 O 4 @NC 20 showed the best rate capability and cycle stability. - Abstract: Combining nanostructure engineering with conductive carbonaceous material is a promising strategy to obtain high-performance lithium ion batteries (LIBs). In this work, spinel NiFe 2 O 4 nanooctahedrons were initially synthesized at a low temperature without further annealing. We investigated the phase formation mechanism by time-dependent experiments. Next, octahedral NiFe 2 O 4 with a nitrogen-doped carbon shell (NiFe 2 O 4 @NC) were successfully fabricated via a subsequent carbonization of polydopamine (PDA). We systematically varied the dopamine content in the NiFe 2 O 4 /carbon nanocomposites and found that a nanocomposite containing 20% mass fraction of dopamine exhibited enhanced lithium ion battery performance with high reversible cycle capacity and good rate retention performance compared with the pure material. Remarkably, the hybrid nanocomposite delivered a high reversible capacity of 1297 mAh g −1 even after 50 cycles at a current density of 100 mA g −1 . Additionally, a high capacity of 1204 mAh g −1 was retained at a high current density of 500 mA g −1 after 300 cycles. This improvement in electrochemical performance is attributed to the enhanced structural stability and electrical conductivity caused by the carbon layer, and is supported by TEM and EIS measurements.

Reversible chemical delithiation/lithiation of LiFePO4: towards a redox flow lithium-ion battery.

Science.gov (United States)

Huang, Qizhao; Li, Hong; Grätzel, Michael; Wang, Qing

2013-02-14

Reversible chemical delithiation/lithiation of LiFePO(4) was successfully demonstrated using ferrocene derivatives, based on which a novel energy storage system--the redox flow lithium-ion battery (RFLB), was devised by integrating the operation flexibility of a redox flow battery and high energy density of a lithium-ion battery. Distinct from the recent semi-solid lithium rechargeable flow battery, the energy storage materials of RFLB stored in separate energy tanks remain stationary upon operation, giving us a fresh perspective on building large-scale energy storage systems with higher energy density and improved safety.

Autoionization resonances in the photoabsorption spectra of Fe{sup n+} iron ions

Energy Technology Data Exchange (ETDEWEB)

Konovalov, A. V., E-mail: alkonvit@yandex.ru; Ipatov, A. N., E-mail: andrei-ipatov@mail.ru [Peter the Great St. Petersburg State Polytechnic University (Russian Federation)

2016-11-15

The photoabsorption cross sections of a neutral iron atom, as well as positive Fe{sup +} and Fe{sup 2+} ions, are calculated in the relativistic random-phase approximation with exchange in the energy range 20–160 eV. The wavefunctions of the ground and excited states are calculated in the single-configuration Hartree–Fock–Dirac approximation. The resultant photoabsorption spectra are compared with experimental data and with the results of calculations based on the nonrelativistic spin-polarized version of the random-phase approximation with exchange. Series of autoionization resonance peaks, as well as giant autoionization resonance lines corresponding to discrete transitions 3p → 3d, are clearly observed in the photoabsorption cross sections. The conformity of the positions of calculated peaks of giant autoionization resonances with experimental data is substantially improved by taking into account additionally the correlation electron–electron interaction based on the model of the dynamic polarization potential.

Continuous preparation of Fe{sub 3}O{sub 4} nanoparticles through Impinging Stream-Rotating Packed Bed reactor and their electrochemistry detection toward heavy metal ions

Energy Technology Data Exchange (ETDEWEB)

Fan, Hong-Lei [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China); Zhou, Shao-Feng [Shanxi Province Key Laboratory of Functional Nanocomposites, North University of China, Taiyuan, 030051 (China); Gao, Jing [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China); Liu, You-Zhi, E-mail: lyzzhongxin@126.com [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China)

2016-06-25

We reported the continuous preparation and electrochemical behavior toward heavy metal ions of the Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs). This Fe{sub 3}O{sub 4} NPs were fabricated through a novel Impinging Stream-Rotating Packed Bed reactor with a high production rate of 2.23 kg/hour. The as-prepared Fe{sub 3}O{sub 4} NPs were quasi-spherical with a mean diameter of about 10 nm and shown the characteristics of superparamagnetism with the saturated magnetization of 60.5 emu/g. The electrochemical characterization of the as-prepared Fe{sub 3}O{sub 4} NPs toward heavy metal ions were evaluated using square wave anodic stripping voltammetry (SWASV) analysis. The results indicated that the modified electrode could be used to individual detection of Pb(II), Cu(II), Hg(II) and Cd(II). In particular, the modified electrode exhibited the selective detection toward Pb(II) with higher sensitivity of 14.9 μA/μM, while the response to Cu(II), Hg(II) and Cd(II) were negligible. Besides, the modified electrode shown good stability and potential practical applicability in the electrochemical determination of Pb(II). This above results offered a simple method for continuous preparation sensing materials in the application field of electrochemical detection of toxic metal ions through the technology of process intensification. - Highlights: • Fe{sub 3}O{sub 4} nanoparticles were continuous prepared through IS-RPB reactor. • The Fe{sub 3}O{sub 4} nanoparticles showed selective detection of heavy metal ions. • It exhibited favorable sensitivity (14.9 μA μM{sup −1}) and LOD (0.119 μM) for Pb(II). • The as-prepared nanoparticles showed favorable potential application.

Tunable morphology synthesis of LiFePO4 nanoparticles as cathode materials for lithium ion batteries.

Science.gov (United States)

Ma, Zhipeng; Shao, Guangjie; Fan, Yuqian; Wang, Guiling; Song, Jianjun; Liu, Tingting

2014-06-25

Olivine LiFePO4 with nanoplate, rectangular prism nanorod and hexagonal prism nanorod morphologies with a short b-axis were successfully synthesized by a solvothermal in glycerol and water system. The influences of solvent composition on the morphological transformation and electrochemical performances of olivine LiFePO4 are systematically investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and galvanostatic charge-discharge tests. It is found that with increasing water content in solvent, the LiFePO4 nanoplates gradually transform into hexagonal prism nanorods that are similar to the thermodynamic equilibrium shape of the LiFePO4 crystal. This indicates that water plays an important role in the morphology transformation of the olivine LiFePO4. The electrochemical performances vary significantly with the particle morphology. The LiFePO4 rectangular prism nanorods (formed in a glycerol-to-water ratio of 1:1) exhibit superior electrochemical properties compared with the other morphological particles because of their moderate size and shorter Li(+) ion diffusion length along the [010] direction. The initial discharge capacity of the LiFePO4@C with a rectangular prism nanorod morphology reaches to 163.8 mAh g(-1) at 0.2 C and over 75 mAh g(-1) at the high discharging rate of 20 C, maintaining good stability at each discharging rate.

Surface Modification of the LiFePO4 Cathode for the Aqueous Rechargeable Lithium Ion Battery.

Science.gov (United States)

Tron, Artur; Jo, Yong Nam; Oh, Si Hyoung; Park, Yeong Don; Mun, Junyoung

2017-04-12

The LiFePO 4 surface is coated with AlF 3 via a simple chemical precipitation for aqueous rechargeable lithium ion batteries (ARLBs). During electrochemical cycling, the unfavorable side reactions between LiFePO 4 and the aqueous electrolyte (1 M Li 2 SO 4 in water) leave a highly resistant passivation film, which causes a deterioration in the electrochemical performance. The coated LiFePO 4 by 1 wt % AlF 3 has a high discharge capacity of 132 mAh g -1 and a highly improved cycle life, which shows 93% capacity retention even after 100 cycles, whereas the pristine LiFePO 4 has a specific capacity of 123 mAh g -1 and a poor capacity retention of 82%. The surface analysis results, which include X-ray photoelectron spectroscopy and transmission electron microscopy results, show that the AlF 3 coating material is highly effective for reducing the detrimental surface passivation by relieving the electrochemical side reactions of the fragile aqueous electrolyte. The AlF 3 coating material has good compatibility with the LiFePO 4 cathode material, which mitigates the surface diffusion obstacles, reduces the charge-transfer resistances and improves the electrochemical performance and surface stability of the LiFePO 4 material in aqueous electrolyte solutions.

Synthesis and modification of FeVO{sub 4} as novel anode for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaolin [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei University, Wuhan 430062 (China); Cao, Yuancheng [Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of chemical and Environment Engineering, Jianghan University, Wuhan 430062 (China); Zheng, Hao; Chen, Xiao [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei University, Wuhan 430062 (China); Feng, Chuanqi, E-mail: cfeng@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei University, Wuhan 430062 (China)

2017-02-01

Graphical abstract: The FeVO{sub 4}/graphene are synthesized by combining hydrothermal and heat treatment method. It delivered an initial discharge capacity of 1302.3 mAh g{sup −1} and remained capacity as 1046.5 mAh g{sup −1} after 100 cycles and behaved better electrochemical properties than that of pure FeVO{sub 4}. - Highlights: • The FeVO{sub 4} and FeVO{sub 4}/graphene are synthesized by combining hydrothermal and heat treatment method. • The FeVO{sub 4}/graphene nanocomposite exhibits outstanding electrochemical performance. • FeVO{sub 4}/graphene delivered an initial discharge capacity of 1302.3 mAh g{sup −1} and remained capacity as 1046.5 mAh g{sup −1} after 100 cycles. • The FeVO{sub 4}/graphene composite behaved better electrochemical properties than that of pure FeVO{sub 4}. - Abstract: FeVO{sub 4} and FeVO{sub 4}/graphene nanorods were synthesized successfully by combining a facile hydrothermal and heat treatment method. The samples were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and transmission electron microscopy (TEM) techniques. The content of graphene in FeVO{sub 4}/graphene was determined by thermogravimetric analysis (TG). The electrochemical properties of the samples were also investigated by battery testing system. The results showed that the FeVO{sub 4} formed were taken on morphology of nanorods with the length between 0.5 and 1 μm and the diameter in range of 50 to 100 nm. Besides, the size of FeVO{sub 4}/graphene was smaller than that of pure FeVO{sub 4}. The content of graphene in composite was about 25.0% by weight. The reversible discharge capacities of FeVO{sub 4} and FeVO{sub 4}/graphene were 405.2 mAh g{sup −1} and 1046.5 mAh g{sup −1} separately after 100 cycles at the current density of 100 mAh g{sup −1} in the voltage range of 0.01–3 V. The reasons for the FeVO{sub 4}/graphene composite to behave outstanding electrochemical properties were also discussed. The Fe

Reduced Graphene Oxide-Wrapped FeS2 Composite as Anode for High-Performance Sodium-Ion Batteries

Science.gov (United States)

Wang, Qinghong; Guo, Can; Zhu, Yuxuan; He, Jiapeng; Wang, Hongqiang

2018-06-01

Iron disulfide is considered to be a potential anode material for sodium-ion batteries due to its high theoretical capacity. However, its applications are seriously limited by the weak conductivity and large volume change, which results in low reversible capacity and poor cycling stability. Herein, reduced graphene oxide-wrapped FeS2 (FeS2/rGO) composite was fabricated to achieve excellent electrochemical performance via a facile two-step method. The introduction of rGO effectively improved the conductivity, BET surface area, and structural stability of the FeS2 active material, thus endowing it with high specific capacity, good rate capability, as well as excellent cycling stability. Electrochemical measurements show that the FeS2/rGO composite had a high initial discharge capacity of 1263.2 mAh g-1 at 100 mA g-1 and a high discharge capacity of 344 mAh g-1 at 10 A g-1, demonstrating superior rate performance. After 100 cycles at 100 mA g-1, the discharge capacity remained at 609.5 mAh g-1, indicating the excellent cycling stability of the FeS2/rGO electrode.

Optimization of NiFe2O4/rGO composite electrode for lithium-ion batteries

Science.gov (United States)

Li, Chen; Wang, Xia; Li, Shandong; Li, Qiang; Xu, Jie; Liu, Xiaomin; Liu, Changkun; Xu, Yuanhong; Liu, Jingquan; Li, Hongliang; Guo, Peizhi; Zhao, Xiu Song

2017-09-01

The combination of carbon compositing and the proper choice of binders in one system offer an effective strategy for improving electrode performance for lithium ion batteries (LIBs). Here, we focus on the optimization of reduced graphene oxide content in NiFe2O4/reduced graphene oxide (abbreviated to NiFe2O4/rGO) composites and the proper choice of binders to enhance the cycling stability of the NiFe2O4 electrode. The NiFe2O4/rGO composites were fabricated by a hydrothermal-annealing method, in which the mean size of spinel NiFe2O4 nanoparticles was approximately 20 nm. When tested as anode materials for LIBs, the NiFe2O4/rGO electrodes with carboxymethylcellulose (CMC) binder exhibited excellent lithium-storage performance including high reversible capacity, good cycling durability and high-rate capability. The capacity could be retained as high as 1105 mAh g-1 at a current density of 100 mA g-1 for over 50 cycles, even cycled at higher current density of 1000 mA g-1, a capacity of 800 mAh g-1can be obtained, whereas the electrode with the polyvinylidene fluoride (PVDF) binder suffered from rapid capacity decay under the same test conditions. As a result, the NiFe2O4/rGO composites with CMC binder electrode in this work are promising as anodes for high-performance LIBs, resulting from the synergistic effect of optimal graphene content and proper choice of binder.

Effects of metal ions on the reactivity and corrosion electrochemistry of Fe/FeS nanoparticles.

Science.gov (United States)

Kim, Eun-Ju; Kim, Jae-Hwan; Chang, Yoon-Seok; Turcio-Ortega, David; Tratnyek, Paul G

2014-04-01

Nano-zerovalent iron (nZVI) formed under sulfidic conditions results in a biphasic material (Fe/FeS) that reduces trichloroethene (TCE) more rapidly than nZVI associated only with iron oxides (Fe/FeO). Exposing Fe/FeS to dissolved metals (Pd(2+), Cu(2+), Ni(2+), Co(2+), and Mn(2+)) results in their sequestration by coprecipitation as dopants into FeS and FeO and/or by electroless precipitation as zerovalent metals that are hydrogenation catalysts. Using TCE reduction rates to probe the effect of metal amendments on the reactivity of Fe/FeS, it was found that Mn(2+) and Cu(2+) decreased TCE reduction rates, while Pd(2+), Co(2+), and Ni(2+) increased them. Electrochemical characterization of metal-amended Fe/FeS showed that aging caused passivation by growth of FeO and FeS phases and poisoning of catalytic metal deposits by sulfide. Correlation of rate constants for TCE reduction (kobs) with electrochemical parameters (corrosion potentials and currents, Tafel slopes, and polarization resistance) and descriptors of hydrogen activation by metals (exchange current density for hydrogen reduction and enthalpy of solution into metals) showed the controlling process changed with aging. For fresh Fe/FeS, kobs was best described by the exchange current density for activation of hydrogen, whereas kobs for aged Fe/FeS correlated with electrochemical descriptors of electron transfer.

Synthesis and Electrochemical Properties of Fe-doped V6O13 as Cathode Material for Lithium-ion Battery

Directory of Open Access Journals (Sweden)

YUAN Qi

2018-01-01

Full Text Available Fe-doped V6O13 was synthesized via a facile hydrothermal method after preparing precursor in order to improve the discharge capacity and cycle performance of V6O13 cathode material at high-lithium state. XRD, SEM and XPS were employed to characterize the phase, morphology and valence of the Fe-doped V6O13. Meanwhile, the electrochemical performance was analyzed and researched. Different morphologies and electrochemical performances of Fe-doped V6O13 were obtained via doping different contents of Fe3+ ion. The sample 0.02 presented the largest thickness of nanosheets (the thickness of 600-900nm and clearance between layers. The Fe-doped V6O13 has a better electrochemical performance than that of pure V6O13. The sample 0.02 exhibits the best electrochemical performance, the initial discharge specific capacity is 433mAh·g-1 and the capacity retention is 47.1% after 100 cycles.

Facile fabrication of composited Mn_3O_4/Fe_3O_4 nanoflowers with high electrochemical performance as anode material for lithium ion batteries

International Nuclear Information System (INIS)

Zhao, Dianyun; Hao, Qin; Xu, Caixia

2015-01-01

Graphical abstract: Mn_3O_4/Fe_3O_4 nanoflowers are successfully prepared through one step dealloying of Mn_5Fe_5Al_9_0 alloy at room temperature. This hierarchical flower-like structure with consists of a packed array of uniform regular hexagon-like nanoslices. Combined with the specific hierarchical flower-like architecture and the synergistic effect exerted by Mn_3O_4 and Fe_3O_4, the nanocomposite exhibits enhanced performance as anode material for lithium ion batteries than pure Mn_3O_4 and Fe_3O_4 anode. - Highlights: • Mn_3O_4/Fe_3O_4 nanoflowers are easily prepared by one step dealloying method. • The nanoflowers consist of packed regular nanoslices with interconnected voids. • Mn_3O_4/Fe_3O_4 nanoflowers deliver higher discharge capacity than Mn_3O_4 and Fe_3O_4. • Mn_3O_4/Fe_3O_4 nanoflowers show lower initial irreversible loss than Mn_3O_4 anode. - Abstract: Mn_3O_4/Fe_3O_4 nanoflowers with controllable components are simply fabricated through one step etching of the Mn_5Fe_5Al_9_0 ternary alloy. The as-made hierarchical flower-like structure with interconnected voids consists of a packed array of uniform regular hexagon-like nanoslices. Based on the simple dealloying strategy the target metals are directly converted to uniform nanocomposite composed of Mn_3O_4 and Fe_3O_4 species. With the unique hierarchical flower-like structure and the synergistic effects between Mn_3O_4 and Fe_3O_4, the nanocomposite exhibits higher performance as anode material for lithium ion batteries than that of pure Mn_3O_4 and Fe_3O_4 anodes. The Mn_3O_4/Fe_3O_4 nanocomposite deliver much higher discharge capacity and lower initial irreversible loss than Mn_3O_4 anode. The Mn_3O_4/Fe_3O_4 anode material also shows an excellent cycling stability at the high rate of 1500 mA g"−"1 with outstanding rate capability. With the advantages of simple preparation and excellent electrochemical performance, Mn_3O_4/Fe_3O_4 nanoflowers manifest great application potential as

In situ X-ray diffraction characterisation of Fe0.5TiOPO4 and Cu0.5TiOPO4 as electrode material for sodium-ion batteries

International Nuclear Information System (INIS)

Bleith, Peter; Kaiser, Hermann; Novák, Petr; Villevieille, Claire

2015-01-01

Na-ion batteries might become a low-cost alternative to Li-ion batteries in the future. Suitable electrode materials, especially anode materials, are needed for Na-ion batteries. As possible candidates Cu 0.5 TiOPO 4 and Fe 0.5 TiOPO 4 were tested. While Cu 0.5 TiOPO 4 does not react with Na + , Fe 0.5 TiOPO 4 shows a specific charge of ≈600 mAh/g upon the first sodiation and 280 mAh/g in the first desodiation. In situ XRD in a new, versatile and reliable in situ cell revealed that Fe 0.5 TiOPO 4 reacts via a conversion type reaction upon sodiation with an amorphisation of the sample

Preparation of new nano magnetic material Fe3O4@g-C3N4 and good adsorption performance on uranium ion

Science.gov (United States)

Long, Wei; Liu, Huijun; Yan, Xueming; Fu, Li

2018-03-01

A new nano magnetic material Fe3O4@g-C3N4 was prepared by deposition reduction method, which performed good adsorption performance to uranium ion. Characterization results showed that the g-C3N4 particles were wrapped around the nano magnetic Fe3O4 particles, and the textural properties of this material was improved, so the adsorption performance to uranium ion was good. Adsorption experiments of this material demonstrated that the optimum pH value was 10, the optimum mass of adsorbent was 6.5 mg and the optimum adsorption time was 150 min in the initial concentration of 140 mg/L uranium ion solution system, and the maximum adsorption capacity was up to 352.1 mg/g and the maximum adsorption rate was more than 90%.

Presence of 60Fe in eucrite Piplia Kalan: A new perspective to the initial 60Fe/ 56Fe in the early solar system

Digital Repository Service at National Institute of Oceanography (India)

Rudraswami, N.G.; Sahijpal, S.; Bhandari, N.

Fe-Ni isotope measurements of ferrous pyroxenes of the Piplia Kalan eucrite using Secondary Ion Mass Spectrometer revealed the presence of sup (60) Ni excess corresponding to the initial 60Fe/56Fe of (5.2 + or - 2.4) × 10 sup(-9). Combining...

High-rate and ultralong cycle-life LiFePO{sub 4} nanocrystals coated by boron-doped carbon as positive electrode for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Feng, Jinpeng, E-mail: goldminer@sina.com; Wang, Youlan

2016-12-30

Highlights: • B-doped carbon decorated LiFePO{sub 4} has been fabricated for the first time. • The LiFePO{sub 4}@B-CdisplaysimprovedbatteryperformancecomparedtoLiFePO{sub 4}@C. • The LiFePO{sub 4}@B-C is good candidate for high-performance lithium-ion batteries. - Abstract: An evolutionary modification approach, boron-doped carbon coating, has been used to improve the electrochemical performances of positive electrodes for lithium-ion batteries, and demonstrates apparent and significant modification effects. In this study, the boron-doped carbon coating is firstly adopted and used to decorate the performance of LiFePO{sub 4}. The obtained composite exhibits a unique core-shell structure with an average diameter of 140 nm and a 4 nm thick boron-doped carbon shell that uniformly encapsulates the core. Owing to the boron element which could induce high amount of defects in the carbon, the electronic conductivity of LiFePO{sub 4} is greatly ameliorated. Thus, the boron-doped composite shows superior rate capability and cycle stability than the undoped sample. For instance, the reversible specific capacity of LiFePO{sub 4}@B{sub 0.4}-C can reach 164.1 mAh g{sup −1} at 0.1C, which is approximately 96.5% of the theoretical capacity (170 mAh g{sup −1}). Even at high rate of 10C, it still shows a high specific capacity of 126.8 mAh g{sup −1} and can be maintained at 124.5 mAh g{sup −1} after 100 cycles with capacity retention ratio of about 98.2%. This outstanding Li-storage property enable the present design strategy to open up the possibility of fabricating the LiFePO{sub 4}@B-C composite for high-performance lithium-ion batteries.

New lithium ion batteries exploiting conversion/alloying anode and LiFe0.25Mn0.5Co0.25PO4 olivine cathode

International Nuclear Information System (INIS)

Lecce, Daniele Di; Verrelli, Roberta; Hassoun, Jusef

2016-01-01

Highlights: • New Li-ion batteries are reported. • LiFe 0.25 Mn 0.5 Co 0.25 PO 4 olivine is used as the cathode. • Either Sn-C or Sn-Fe 2 O 3 -C composites are used as anodes. • The electrode/electrolyte interfaces are monitored by EIS. • The systems are considered suitable for energy storage - Abstract: New Li-ion cells are formed by combining a LiFe 0.25 Mn 0.5 Co 0.25 PO 4 olivine cathode either with Sn-Fe 2 O 3 -C or with Sn-C composite anodes. These active materials exhibit electrochemical properties very attractive in view of practical use, including the higher working voltage of the LiFe 0.25 Mn 0.5 Co 0.25 PO 4 cathode with respect to conventional LiFePO 4 , as well as the remarkable capacity and rate capability of Sn-Fe 2 O 3 -C and Sn-C anodes. The stable electrode/electrolyte interfaces, demonstrated by electrochemical impedance spectroscopy, along with proper mass balancing and anode pre-lithiation, allow stable galvanostatic cycling of the full cells. The two batteries, namely Sn-Fe 2 O 3 -C/LiFe 0.25 Mn 0.5 Co 0.25 PO 4 and Sn-C/LiFe 0.25 Mn 0.5 Co 0.25 PO 4 , reversibly operate revealing promising electrochemical features in terms of delivered capacity, working voltage and stability, thus suggesting these electrodes combinations as suitable alternatives for an efficient energy storage.

Magnetic properties of Fe-doped NiO nanoparticles

Science.gov (United States)

Kurokawa, A.; Sakai, N.; Zhu, L.; Takeuchi, H.; Yano, S.; Yanoh, T.; Onuma, K.; Kondo, T.; Miike, K.; Miyasaka, T.; Ichiyanagi, Y.

2013-08-01

Ni1- x Fe x O ( x = 0, 0.05, 0.1) nanoparticles with several nanometers encapsulated with amorphous SiO2 were prepared by our novel preparation method. A NiO single phase structure was confirmed using the X-ray diffraction measurements. It is considered that Ni ions are replaced by Fe ions because it is observed that the lattice constant decreases. The temperature dependence behavior of the magnetization revealed that the blocking temperature, T B , shifted from 17 to 57 K as the amount of Fe ions increased, and that below T B , ferromagnetic behaviors were exhibited. The coercive force, H C , increased from 0.8 to 1.5 kOe as the amount of Fe ions increased.

Orientation-dependent ion beam sputtering at normal incidence conditions in FeSiAl alloy

International Nuclear Information System (INIS)

Batic, Barbara Setina; Jenko, Monika

2010-01-01

The authors have performed Ar+ broad ion beam sputtering of a polycrystalline Fe-Si-Al alloy at normal incidence at energies varying from 6 to 10 keV. Sputtering results in the formation of etch pits, which can be classified in three shapes: triangular, rectangular, and square. As each grain of individual orientation exhibits a certain type of pattern, the etch pits were correlated with the crystal orientations by electron backscattered diffraction technique.

Double Carbon Nano Coating of LiFePO4 Cathode Material for High Performance of Lithium Ion Batteries.

Science.gov (United States)

Ding, Yan-Hong; Huang, Guo-Long; Li, Huan-Huan; Xie, Hai-Ming; Sun, Hai-Zhu; Zhang, Jing-Ping

2015-12-01

Double carbon-coated LiFePO4 (D-LiFePO4/C) composite with sphere-like structure was synthesized through combination of co-precipitation and solid-state methods. Cetyl-trimethyl-ammonium bromide (CTAB) and citric acid served as two kinds of carbon sources in sequence. SEM images demonstrated that double carbon coating had certain influence on the morphology. The thickness of carbon coating on D-LiFePO4/C was about 1.7 nm and the content of carbon was 2.48 wt%, according to HRTEM and TG analysis. The electrochemical impedance spectroscopy analysis indicated that the D-LiFePO4/C composite presented the charge-transfer resistance of 68 Ω and Li ion diffusion coefficient of 2.68 x 10(-13) cm2 S(-1), while the single carbon-coated LiFePO4 (S-LiFePO4/C) exhibited 135.5Ω and 4.03 x 10(-14) cm2 S(-1). Especially, the prepared D-LiFePO4/C electrode showed discharge capacities of 102.9 (10C) and 87.1 (20C) mA h g(-1), respectively, with almost no capacity lost after 400 cycles at 10C, which were much better than those of S-LiFePO4/C composite.

Fe3O4/Reduced Graphene Oxide Nanocomposite: Synthesis and Its Application for Toxic Metal Ion Removal

Directory of Open Access Journals (Sweden)

Nguyen Thi Vuong Hoan

2016-01-01

Full Text Available The synthesis of reduced graphene oxide modified by magnetic iron oxide (Fe3O4/rGO and its application for heavy metals removal were demonstrated. The obtained samples were characterized by X-ray diffraction (XRD, nitrogen adsorption/desorption isotherms, X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectroscopy (FT-IR, and magnetic measurement. The results showed that the obtained graphene oxide (GO contains a small part of initial graphite as well as reduced oxide graphene. GO exhibits very high surface area in comparison with initial graphite. The morphology of Fe3O4/rGO consists of very fine spherical iron nanooxide particles in nanoscale. The formal kinetics and adsorption isotherms of As(V, Ni(II, and Pb(II over obtained Fe3O4/rGO have been investigated. Fe3O4/rGO exhibits excellent heavy metal ions adsorption indicating that it is a potential adsorbent for water sources contaminated by heavy metals.

Fine structure of an exciton coupled to a single Fe2 + ion in a CdSe/ZnSe quantum dot

Science.gov (United States)

Smoleński, T.; Kazimierczuk, T.; Goryca, M.; Pacuski, W.; Kossacki, P.

2017-10-01

We present a polarization-resolved photoluminescence study of the exchange interaction effects in a prototype system consisting of an individual Fe2 + ion and a single neutral exciton confined in a CdSe/ZnSe quantum dot. A maximal possible number of eight fully linearly polarized lines in the bright exciton emission spectrum is observed, evidencing complete degeneracy lifting in the investigated system. We discuss the conditions required for such a scenario to take place: anisotropy of the electron-hole interaction and the zero-field splitting of the Fe2 + ion spin states. Neglecting either of these components is shown to restore partial degeneracy of the transitions, making the excitonic spectrum similar to those previously reported for all other systems of quantum dots with single magnetic dopants.

Characterisation of PEEK, PET and PI implanted with 80 keV Fe+ ions to high fluencies

Czech Academy of Sciences Publication Activity Database

Macková, Anna; Malinský, Petr; Mikšová, Romana; Hnatowicz, Vladimír; Khaibullin, R. I.; Slepička, P.; Švorčík, V.

2014-01-01

Roč. 331, JUL (2014), s. 176-181 ISSN 0168-583X R&D Projects: GA ČR GA106/09/0125; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : Fe ion implantation * polymers * depth profiles * RBS * TEM * UV Vis Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.124, year: 2014

A three-dimensional LiFePO4/carbon nanotubes/graphene composite as a cathode material for lithium-ion batteries with superior high-rate performance

International Nuclear Information System (INIS)

Lei, Xingling; Zhang, Haiyan; Chen, Yiming; Wang, Wenguang; Ye, Yipeng; Zheng, Chuchun; Deng, Peng; Shi, Zhicong

2015-01-01

Graphical abstract: The excellent electrochemical performances can be attributed to the synergistic effect of CNTs and graphene. - Highlights: • The LFP–CNT–G composite was successfully prepared by solid station method. • The interlaced CNTs reduced the crumple of graphene and improved tap density of the composite. • The LFP–CNT–G electrode exhibited superior electrochemical performance. - Abstract: A three-dimensional lithium iron phosphate (LiFePO 4 )/carbon nanotubes (CNTs)/graphene composite was successfully synthesized via solid-state reaction. The LiFePO 4 /carbon nanotubes/graphene (LFP–CNT–G) composite used as Li-ions battery cathode material exhibits superior high-rate capability and favorable charge–discharge cycle performance under relative high current density compared with that of LiFePO 4 /carbon nanotubes (LFP–CNT) composite and LiFePO 4 /graphene (LFP–G) composite. Graphene nanosheets and CNTs construct 3D conducting networks are favor for faster electron transfer, higher Li-ions diffusion coefficient and lower resistance during the Li-ions reversible reaction. The synergistic effect of graphene nanosheets and CNTs improves the rate capability and cycling stability of LiFePO 4 -based cathodes. The LFP–CNT–G electrode shows reversible capacity of 168.9 mA h g −1 at 0.2 C and 115.8 mA h g −1 at 20 C. The electrochemical impedance spectroscopy demonstrate that the LFP–CNT–G electrode has the smallest charge-transfer resistance, indicating that the fast electron transfer from the electrolyte to the LFP–CNT–G active materials in the Li-ions intercalation/deintercalation reactions owing to the three-dimensional networks of graphene and carbon nanotubes

Bio-synthesis participated mechanism of mesoporous LiFePO4/C nanocomposite microspheres for lithium ion battery

DEFF Research Database (Denmark)

Zhang, X.D.; He, W.; Yue, Yuanzheng

2012-01-01

specific surface area (203 m2 g-1). The microsphere is composed of densely aggregated nanoparticles and interconnected nanopores. The open mesoporous structure allows lithium ions easily to penetrate into the spheres, while a thorough coating of the biocarbon network on the surface of the LiFePO4...... nanoparticles facilitates lithium ion and electron diffusion. The MP-LFP/C-NC-MS have high discharge capacity of about 158.5 mA h g−1 at the current density of 0.1 C, discharge capacity of 122 mA h g−1 at 10 C, and high capacity retention rate. Therefore the mesoporous microspheres are an ideal type of cathode......-active materials for making high-power Li-ion batteries....

Nano-size metallic oxide particle synthesis in Fe-Cr alloys by ion implantation

Science.gov (United States)

Zheng, C.; Gentils, A.; Ribis, J.; Borodin, V. A.; Delauche, L.; Arnal, B.

2017-10-01

Oxide Dispersion Strengthened (ODS) steels reinforced with metal oxide nanoparticles are advanced structural materials for nuclear and thermonuclear reactors. The understanding of the mechanisms involved in the precipitation of nano-oxides can help in improving mechanical properties of ODS steels, with a strong impact for their commercialization. A perfect tool to study these mechanisms is ion implantation, where various precipitate synthesis parameters are under control. In the framework of this approach, high-purity Fe-10Cr alloy samples were consecutively implanted with Al and O ions at room temperature and demonstrated a number of unexpected features. For example, oxide particles of a few nm in diameter could be identified in the samples already after ion implantation at room temperature. This is very unusual for ion beam synthesis, which commonly requires post-implantation high-temperature annealing to launch precipitation. The observed particles were composed of aluminium and oxygen, but additionally contained one of the matrix elements (chromium). The crystal structure of aluminium oxide compound corresponds to non-equilibrium cubic γ-Al2O3 phase rather than to more common corundum. The obtained experimental results together with the existing literature data give insight into the physical mechanisms involved in the precipitation of nano-oxides in ODS alloys.

Research and analysis on electrochemical performances of α-Fe{sub 2}O{sub 3} electrode in Li-ion battery with different current collectors

Energy Technology Data Exchange (ETDEWEB)

Huang, Lihong, E-mail: huang.lihong@foxmail.com; Min, Zhonghua; Zhang, Qinyong

2015-06-15

Highlights: • We achieved a reversible capacity of 415 mAh g{sup −1} after 30 cycles for α-Fe{sub 2}O{sub 3} electrode in Li-ion battery. • Better electrical performance was obtained when using Cu foam as current collector. • As current collector for α-Fe{sub 2}O{sub 3} electrode, Cu foam is better than Cu foil and Ni foam. • It could avoid the active materials falling off from the current collector during cycling. • It is owe to smaller surface film resistance, charge-transfer resistance, etc. - Abstract: In this work, we reported a simple synthesis of submicron α-Fe{sub 2}O{sub 3} with rod-like structure. When it evaluated as electrode material for lithium ion battery, comparing with Cu foil and Ni foam, the as-prepared α-Fe{sub 2}O{sub 3} electrodes with Cu foam current collector exhibited higher reversible capacity of 415 mAh g{sup −1} and more stable cycle performance after 30 cycles. Comparative researches on electrochemical performances of the α-Fe{sub 2}O{sub 3} employing different current collectors (Cu foil, Cu foam and Ni foam) were discussed here in detail. According to our results, the improved electrochemical behaviors of α-Fe{sub 2}O{sub 3} electrode with Cu foam current collector could be attributed to its particular electrode structure, i.e., porous, good electric conductivity, closed adhere to the electrode materials. Just because of that, it may make sure an easy accessibility of electrolytes and fast transportation of lithium ions, importantly, it could avoid the active materials falling off from the current collector on account of volume expansion.

Si effects on radiation induced segregation in high purity Fe-18Cr-14Ni alloys irradiated by Ni ions

International Nuclear Information System (INIS)

Ohta, Joji; Kako, Kenji; Mayuzumi, Masami; Kusanagi, Hideo; Suzuki, Takayoshi

1999-01-01

To illustrate the effects of the element Si on radiation induced segregation, which causes irradiation assisted stress corrosion cracking (IASCC), we investigated grain boundary chemistry of high purity Fe-18Cr-14Ni-Si alloys irradiated by Ni ions using FE-TEM. The addition of Si up to 1% does not affect the Cr depletion at grain boundaries, while it slightly enhances the depletion of Fe and the segregation of Ni and Si. The addition of 2% Si causes the depletion of Cr and Fe and the segregation of Ni and Si at grain boundaries. Thus, the Si content should be as low as possible. In order to reduce the depletion of Cr at grain boundaries, which is one of the major causes of IASCC, Si content should be less than 1%. (author)

Uniform hollow Fe3O4 spheres prepared by template-free solvothermal method as anode material for lithium-ion batteries

International Nuclear Information System (INIS)

Zhang Jingjing; Yao Yu; Huang Tao; Yu Aishui

2012-01-01

Graphical abstract: Unique hollow Fe 3 O 4 spheres assembled by Fe 3 O 4 nanoparticles prepared by a simple template-free solvothermal reaction are tested as anode material for lithium-ion batteries. The results show that the material delivers reversible specific capacities of 870 mA h g −1 even after 50 cycles at 100 mA g −1 and 836 mA h g −1 at 500 mA g −1 . The excellent electrochemical performance can be attributed to their hollow nanostructure and excellent structural stability. Highlights: ► Uniform hollow Fe 3 O 4 spheres were prepared by a template-free solvothermal method. ► The hollow Fe 3 O 4 spheres have the capacity of 870 mA h g −1 at 50th cycle. ► The specific capacity can be well maintained at a large current density. ► The hollow Fe 3 O 4 spheres exhibit enhanced rate capability. ► Electrochemical performance of hollow Fe 3 O 4 spheres is better than Fe 3 O 4 powders. - Abstract: Unique hollow Fe 3 O 4 spheres are prepared by a simple template-free solvothermal reaction. In the reaction, ethylene glycol (EG) and polyvinylpyrrolidone (PVP) serve as the reducing agent and surface stabilizer, respectively. NH 4 Ac plays the role of the structure-directing agent, which combines with the Ostwald ripening process, resulting in the favored formation of hollow structures. The morphologies and structures are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The hollow Fe 3 O 4 spheres exhibit excellent cycling and rate performance as anode material for lithium-ion batteries, delivering reversible specific capacities of 870 mA h g −1 even after 50 cycles at 100 mA g −1 and 836 mA h g −1 at 500 mA g −1 . The excellent electrochemical performance can be attributed to their hollow nanostructure and excellent structural stability.

An X- and Q-band Fe{sup 3+} EPR study of nanoparticles of magnetic semiconductor Zn{sub 1−x}Fe{sub x}O

Energy Technology Data Exchange (ETDEWEB)

Misra, Sushil K., E-mail: skmisra@alcor.concordia.ca [Physics Department, Concordia University, Montreal, QC, Canada H3G 1M8 (Canada); Andronenko, S.I. [Physics Institute, Kazan Federal University, Kazan 420008 (Russian Federation); Thurber, A.; Punnoose, A. [Department of Physics, Boise State University, Boise, ID 83725-1570 (United States); Nalepa, A. [Max-Planck-Institut für Chemische Energie Konversion, Stifstrasse 34-36, 45470 Mülheim an der Ruhr (Germany)

2014-08-01

EPR studies on two types of nanoparticles of Fe{sup 3+} doped, 0.1–10%, ZnO, NL and QJ, prepared using similar chemical hydrolysis methods, in diethylene glycol, and in denatured ethanol solutions, respectively, were carried out at X-band (∼9.5 GHz) at 77 K and at Q-band (∼34.0 GHz) at 10, 80, and 295 K. To interpret the experimental results, EPR spectra were simulated by exact diagonalization of the spin-Hamiltonian matrix to identify the Fe ions at different magnetically active sites in these samples. The simulation for NL samples revealed that they contained (i) Fe{sup 3+} ions, which substituted for Zn ions, the zero-field splitting (ZFS) parameter which has a large distribution over the sample due to oxygen vacancies in the second coordination sphere; (ii) EPR signal from surface oxygen defects; and (iii) ferromagnetically (FM) coupled Fe ions with concentration of Fe more than 1%. The EPR spectra for QJ samples are very different from those for NL samples, exhibiting only rather intense FM EPR lines. The FM and EPR spectra in NL and/or QJ samples are found to vary strongly with differences in the surface morphology of nanoparticles. - Highlights: • X and Q band EPR studies on NL and QJ nanoparticles of Fe{sup 3+} doped ZnO at 10, 80, and 295 K. • Fe ions are present at different magnetically active sites in these samples. • NL samples consist of paramagnetic Fe{sup 3+} ions, and ferromagnetically coupled Fe ions. • QJ samples exhibit only intense ferromagnetic lines, different from QJ. • Spectra vary strongly with the surface morphology of nanoparticles.

Multi-jump magnetic switching in ion-beam sputtered amorphous Co20Fe60B20 thin films

International Nuclear Information System (INIS)

Raju, M.; Chaudhary, Sujeet; Pandya, D. K.

2013-01-01

Unconventional multi-jump magnetization reversal and significant in-plane uniaxial magnetic anisotropy (UMA) in the ion-beam sputtered amorphous Co 20 Fe 60 B 20 (5–75 nm) thin films grown on Si/amorphous SiO 2 are reported. While such multi-jump behavior is observed in CoFeB(10 nm) film when the magnetic field is applied at 10°–20° away from the easy-axis, the same is observed in CoFeB(12.5 nm) film when the magnetic field is 45°–55° away from easy-axis. Unlike the previous reports of multi-jump switching in epitaxial films, their observance in the present case of amorphous CoFeB is remarkable. This multi-jump switching is found to disappear when the films are crystallized by annealing at 420 °C. The deposition geometry and the energy of the sputtered species appear to intrinsically induce a kind of bond orientation anisotropy in the films, which leads to the UMA in the as-grown amorphous CoFeB films. Exploitation of such multi-jump switching in amorphous CoFeB thin films could be of technological significance because of their applications in spintronic devices

Soft magnetic properties of hybrid ferromagnetic films with CoFe, NiFe, and NiFeCuMo layers

Energy Technology Data Exchange (ETDEWEB)

Choi, Jong-Gu [Eastern-western Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Hwang, Do-Guwn [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Rhee, Jang-Roh [Dept. of Physics, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Lee, Sang-Suk, E-mail: sslee@sangji.ac.kr [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of)

2011-09-30

Two-layered ferromagnetic alloy films (NiFe and CoFe) with intermediate NiFeCuMo soft magnetic layers of different thicknesses were investigated to understand the relationship between coercivity and magnetization process by taking into account the strength of hard-axis saturation field. The thickness dependence of H{sub EC} (easy-axis coercivity), H{sub HS} (hard-axis saturation field), and {chi} (susceptibility) of the NiFeCuMo thin films in glass/Ta(5 nm)/[CoFe or NiFe(5 nm-t/2)]/NiFeCuMo(t = 0, 4, 6, 8, 10 nm)/[CoFe or NiFe(5 nm-t/2)]/Ta(5 nm) films prepared using the ion beam deposition method was determined. The magnetic properties (H{sub EC}, H{sub HS}, and {chi}) of the ferromagnetic CoFe, NiFe three-layers with an intermediate NiFeCuMo super-soft magnetic layer were strongly dependent on the thickness of the NiFeCuMo layer.

Carbon-Coated Fe3O4/VOx Hollow Microboxes Derived from Metal-Organic Frameworks as a High-Performance Anode Material for Lithium-Ion Batteries.

Science.gov (United States)

Zhao, Zhi-Wei; Wen, Tao; Liang, Kuang; Jiang, Yi-Fan; Zhou, Xiao; Shen, Cong-Cong; Xu, An-Wu

2017-02-01

As the ever-growing demand for high-performance power sources, lithium-ion batteries with high storage capacities and outstanding rate performance have been widely considered as a promising storage device. In this work, starting with metal-organic frameworks, we have developed a facile approach to the synthesis of hybrid Fe 3 O 4 /VO x hollow microboxes via the process of hydrolysis and ion exchange and subsequent calcination. In the constructed architecture, the hollow structure provides an efficient lithium ion diffusion pathway and extra space to accommodate the volume expansion during the insertion and extraction of Li + . With the assistance of carbon coating, the obtained Fe 3 O 4 /VO x @C microboxes exhibit excellent cyclability and enhanced rate performance when employed as an anode material for lithium-ion batteries. As a result, the obtained Fe 3 O 4 /VO x @C delivers a high Coulombic efficiency (near 100%) and outstanding reversible specific capacity of 742 mAh g -1 after 400 cycles at a current density of 0.5 A g -1 . Moreover, a remarkable reversible capacity of 556 mAh g -1 could be retained even at a current density of 2 A g -1 . This study provides a fundamental understanding for the rational design of other composite oxides as high-performance electrode materials for lithium-ion batteries.

Solid-state reaction in Fe/V multilayers by ion beam mixing with thermal annealing

International Nuclear Information System (INIS)

Borges, J.F.M.; Costa, M.I. da Jr.; Teixeira, S.R.; Cunha, J.B.M. da; Alves, M.C.M.

2001-01-01

We report a study on the structural and magnetic properties of iron-vanadium thin films, originally grown in multilayer form [Fe(20 A)/V(20 A)] 20 , and mixed by ion beam mixing (IBM) and a subsequent thermal treatment. The samples were structurally characterised by X-ray diffraction (XRD) in the θ-2θ geometry and X-ray absorption spectroscopy (XAS). The magnetic characterisation was made using conversion electron Moessbauer spectroscopy (CEMS). The XRD result for the as-deposited multilayer shows a high-degree crystallinity, while CEMS suggests abrupt interface, since no significant contribution from vanadium in iron is observed. After the IBM and thermal treatment, the results from XRD show an FeV solid solution indexed as a bcc-disordered structure (α phase). XAS structural results are consistent with the XRD observations. CEMS results show a magnetic moment reduction for mixed samples

Effect of irradiation temperature on crystallization of {alpha}-Fe induced by He irradiations in Fe{sub 80}B{sub 20} amorphous alloy

Energy Technology Data Exchange (ETDEWEB)

San-noo, Toshimasa; Toriyama, Tamotsu; Wakabayashi, Hidehiko; Iijima, Hiroshi [Musashi Inst. of Tech., Tokyo (Japan); Hayashi, Nobuyuki; Sakamoto, Isao

1997-03-01

Since amorphous alloys are generally highly resistant to irradiation and their critical radiation dose is an order of magnitude higher for Fe-B amorphous alloy than Mo-methods, these alloys are expected to become applicable as for fusion reactor materials. The authors investigated {alpha}-Fe crystallization in an amorphous alloy, Fe{sub 80}B{sub 20} using internal conversion electron Moessbauer spectroscopy. The amount of {alpha}-Fe component was found to increase by raising the He-irradiation dose. The target part was modified to enable He ion radiation at a lower temperature (below 400 K) by cooling with Peltier element. Fe{sub 80}B{sub 20} amorphous alloy was cooled to keep the temperature at 300 K and exposed to 40 keV He ion at 1-3 x 10{sup 8} ions/cm{sup 2}. The amount of {alpha}-Fe crystal in each sample was determined. The crystal formation was not observed for He ion radiation below 2 x 10{sup 18} ions/cm{sup 2}, but that at 3 x 10{sup 8} ions/ cm{sup 2} produced a new phase ({delta} +0.40 mm/sec, {Delta} = 0.89 mm/sec). The decrease in the radiation temperature from 430 to 300 K resulted to extremely repress the production of {alpha}-Fe crystal, suggesting that the crystallization induced by He-radiation cascade is highly depending on the radiation temperature. (M.N.)

Freeze-drying synthesis of three-dimensional porous LiFePO{sub 4} modified with well-dispersed nitrogen-doped carbon nanotubes for high-performance lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Tu, Xiaofeng; Zhou, Yingke, E-mail: zhouyk888@hotmail.com; Song, Yijie

2017-04-01

Highlights: • Three-dimensional porous LiFePO{sub 4}/N-CNTs is synthesized by a freeze-drying method. • The N-CNTs conductive network enhances the electron transport within the LiFePO{sub 4} electrode. • The continuous pores accelerate the diffusion of lithium ions. • LiFePO{sub 4}/N-CNTs demonstrates an excellent electrochemical Li-insertion performance. - Abstract: The three-dimensional porous LiFePO{sub 4} modified with uniformly dispersed nitrogen-doped carbon nanotubes has been successfully prepared by a freeze-drying method. The morphology and structure of the porous composites are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performances are evaluated using the constant current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The nitrogen-doped carbon nanotubes are uniformly dispersed inside the porous LiFePO{sub 4} to construct a superior three-dimensional conductive network, which remarkably increases the electronic conductivity and accelerates the diffusion of lithium ion. The porous composite displays high specific capacity, good rate capability and excellent cycling stability, rendering it a promising positive electrode material for high-performance lithium-ion batteries.

The preparation and electrochemical performances of LiFePO4-multiwalled nanotubes composite cathode materials for lithium ion batteries

International Nuclear Information System (INIS)

Feng Yan

2010-01-01

LiFePO 4 -MWCNTs (multi-walled carbon nanotubes) composite cathode materials were prepared by mixing LiFePO 4 and MWCNTs in ethanol followed by heat-treatment at 500 deg. C for 5 h. The structural, morphology and electrochemical performances of LiFePO 4 -MWCNTs composite materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge-discharge cycle tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicated that MWCNTs adding improved the electronic conductivity, the discharge capacity, cycle stability and lithium ion diffusion kinetics of LiFePO 4 , but MWCNTs adding did not charge the orthorhombic olivine-type structure of LiFePO 4 . In all these prepared LiFePO 4 with x wt.% MWCNTs (x = 4, 7, 10) composites, 7 wt.% MWCNTs adding composite cathode shows the best electrochemical performance, which gets an initial discharge capacity of 152.7 mAh g -1 at 0.18 C discharge rates with capacity retention ratio of 97.77% after 100 cycles.

Ion mass dependence of irradiation-induced local creation of ferromagnetism in Fe60Al40 alloys

International Nuclear Information System (INIS)

Fassbender, J.; Liedke, M. O.; Strache, T.; Moeller, W.; Menendez, E.; Sort, J.; Rao, K. V.; Deevi, S. C.; Nogues, J.

2008-01-01

Ion irradiation of Fe 60 Al 40 alloys results in the phase transformation from the paramagnetic, chemically ordered B2 phase to the ferromagnetic, chemically disordered A2 phase. The magnetic phase transformation is related to the number of displacements per atom (dpa) during the irradiation. For heavy ions (Ar + , Kr + , and Xe + ), a universal curve is observed with a steep increase in the fraction of the ferromagnetic phase that reaches saturation, i.e., a complete phase transformation, at about 0.5 dpa. This proves the purely ballistic nature of the disordering process. If light ions are used (He + and Ne + ), a pronounced deviation from the universal curve is observed. This is attributed to bulk vacancy diffusion from the dilute collision cascades, which leads to a partial recovery of the thermodynamically favored B2 phase. Comparing different noble gas ion irradiation experiments allows us to assess the corresponding counteracting contributions. In addition, the potential to create local ferromagnetic areas embedded in a paramagnetic matrix is demonstrated

Conduction Mechanism by Using CBH Model in Fe3+ and Mn3+ Ion Modified Pb(Zr0.65−xAxTi0.35O3 (A = Mn3+/Fe3+ Ceramics

Directory of Open Access Journals (Sweden)

Niranjan Sahu

2013-01-01

Full Text Available Polycrystalline samples of manganese and iron substituted lead zirconium titanate (PZT with general formula Pb(Zr0.65−xAxTi0.35O3 (A = Mn3+ and Fe3+ ceramics have been synthesized by high temperature solid state reaction technique. X-ray diffraction (XRD patterns were recorded at room temperature to study the crystal structure. All the patterns could be refined by employing the Rietveld method to R3c space group with rhombohedral symmetry. Microstructural properties of the materials were analyzed by scanning electron microscope (SEM, and compositional analysis was carried out by energy dispersive spectrum (EDS measurements. All the materials exhibit ferroelectric to paraelectric transition. The variation of dielectric constant and loss tangent with temperature and frequency is investigated. The decrease of activation energy and increases of AC conductivity with the Fe3+ or Mn3+ ion concentration have been observed. The AC conductivity has been analyzed by the power law. The frequency exponent with the function of temperature has been analyzed by assuming that the AC conduction mechanism is the correlated barrier hopping (CBH model. The conduction in the present sample is found to be of bipolaron type for Mn3+ ion-doped sample. However, the conduction mechanism could not be explained by CBH model for Fe3+ ion-doped sample.

Role of PO4 tetrahedron in LiFePO4 and FePO4 system.

Science.gov (United States)

Zeng, Yuewu

2015-06-01

Using high resolution transmission electron microscopy with image simulation and Fourier analysis, the Li1- x FePO4 (x < 0.01), Li1- x FePO4 (x ∼ 0.5), and FePO4 particles, prepared by charging or discharging the 053048 electrochemical cells (thickness: 5 mm, width: 30 mm, height: 48 mm) and dismantled inside an Ar-filled dry box, were investigated. The high resolution images reveal: (1) the solid solution of Li1- x FePO4 (x < 0.01) contains some missing Li ions leading PO4 group distorted around M1 tunnel of the unit cell; (2) the texture of the particles of Li1- x FePO4 (x ∼0.5) has homogeneously distributed compositional domains of LiFePO4 and FePO4 resulting from spinodal decomposition which promote Li ion easily getting into the particle due to uphill diffusion, (3) the particles of FePO4 formed in charging have heavily distorted lattice and contain some isolated LiFePO4 , (4) interface between LiFePO4 and FePO4 and between amorphous and crystal region provides the lattice distortion of small polarons. © 2015 Wiley Periodicals, Inc.

Scattering of atomic and molecular ions from single crystal surfaces of Cu, Ag and Fe

International Nuclear Information System (INIS)

Zoest, J.M. van.

1986-01-01

This thesis deals with analysis of crystal surfaces of Cu, Ag and Fe with Low Energy Ion scattering Spectroscopy (LEIS). Different atomic and molecular ions with fixed energies below 7 keV are scattered by a metal single crystal (with adsorbates). The energy and direction of the scattered particles are analysed for different selected charge states. In that way information can be obtained concerning the composition and atomic and electronic structure of the single crystal surface. Energy spectra contain information on the composition of the surface, while structural atomic information is obtained by direction measurements (photograms). In Ch.1 a description is given of the experimental equipment, in Ch.2 a characterization of the LEIS method. Ch.3 deals with the neutralization of keV-ions in surface scattering. Two different ways of data interpretation are presented. First a model is treated in which the observed directional dependence of neutralization action of the first atom layer of the surface is presented by a laterally varying thickness of the neutralizing layer. Secondly it is shown that the data can be reproduced by a more realistic, physical model based on atomic transition matrix elements. In Ch.4 the low energy hydrogen scattering is described. The study of the dissociation of H 2 + at an Ag surface r0230ted in a model based on electronic dissociation, initialized by electron capture into a repulsive (molecular) state. In Ch.5 finally the method is applied to the investigation of the surface structure of oxidized Fe. (Auth.)

Discovery of Suprathermal Ionospheric Origin Fe+ in and Near Earth's Magnetosphere

Science.gov (United States)

Christon, S. P.; Hamilton, D. C.; Plane, J. M. C.; Mitchell, D. G.; Grebowsky, J. M.; Spjeldvik, W. N.; Nylund, S. R.

2017-11-01

Suprathermal (87-212 keV/e) singly charged iron, Fe+, has been discovered in and near Earth's 9-30 RE equatorial magnetosphere using 21 years of Geotail STICS (suprathermal ion composition spectrometer) data. Its detection is enhanced during higher geomagnetic and solar activity levels. Fe+, rare compared to dominant suprathermal solar wind and ionospheric origin heavy ions, might derive from one or all three candidate lower-energy sources: (a) ionospheric outflow of Fe+ escaped from ion layers near 100 km altitude, (b) charge exchange of nominal solar wind iron, Fe+≥7, in Earth's exosphere, or (c) inner source pickup Fe+ carried by the solar wind, likely formed by solar wind Fe interaction with near-Sun interplanetary dust particles. Earth's semipermanent ionospheric Fe+ layers derive from tons of interplanetary dust particles entering Earth's atmosphere daily, and Fe+ scattered from these layers is observed up to 1000 km altitude, likely escaping in strong ionospheric outflows. Using 26% of STICS's magnetosphere-dominated data when possible Fe+2 ions are not masked by other ions, we demonstrate that solar wind Fe charge exchange secondaries are not an obvious Fe+ source. Contemporaneous Earth flyby and cruise data from charge-energy-mass spectrometer on the Cassini spacecraft, a functionally identical instrument, show that inner source pickup Fe+ is likely not important at suprathermal energies. Consequently, we suggest that ionospheric Fe+ constitutes at least a significant portion of Earth's suprathermal Fe+, comparable to the situation at Saturn where suprathermal Fe+ is also likely of ionospheric origin.

Melatonin Protects Human Cells from Clustered DNA Damages, Killing and Acquisition of Soft Agar Growth Induced by X-rays or 970 MeV/n Fe ions

Energy Technology Data Exchange (ETDEWEB)

Das, B.; Sutherland, B.; Bennett, P. V.; Cutter, N. C.; Sutherland, J. C.

2011-06-01

We tested the ability of melatonin (N-acetyl-5 methoxytryptamine), a highly effective radical scavenger and human hormone, to protect DNA in solution and in human cells against induction of complex DNA clusters and biological damage induced by low or high linear energy transfer radiation (100 kVp X-rays, 970 MeV/nucleon Fe ions). Plasmid DNA in solution was treated with increasing concentrations of melatonin (0.0-3.5 mM) and were irradiated with X-rays. Human cells (28SC monocytes) were also irradiated with X-rays and Fe ions with and without 2 mM melatonin. Agarose plugs containing genomic DNA were subjected to Contour Clamped Homogeneous Electrophoretic Field (CHEF) followed by imaging and clustered DNA damages were measured by using Number Average length analysis. Transformation experiments on human primary fibroblast cells using soft agar colony assay were carried out which were irradiated with Fe ions with or without 2 mM melatonin. In plasmid DNA in solution, melatonin reduced the induction of single- and double-strand breaks. Pretreatment of human 28SC cells for 24 h before irradiation with 2 mM melatonin reduced the level of X-ray induced double-strand breaks by {approx}50%, of abasic clustered damages about 40%, and of Fe ion-induced double-strand breaks (41% reduction) and abasic clusters (34% reduction). It decreased transformation to soft agar growth of human primary cells by a factor of 10, but reduced killing by Fe ions only by 20-40%. Melatonin's effective reduction of radiation-induced critical DNA damages, cell killing, and striking decrease of transformation suggest that it is an excellent candidate as a countermeasure against radiation exposure, including radiation exposure to astronaut crews in space travel.

Formation of β-FeSi 2 thin films by partially ionized vapor deposition

Science.gov (United States)

Harada, Noriyuki; Takai, Hiroshi

2003-05-01

The partially ionized vapor deposition (PIVD) is proposed as a new method to realize low temperature formation of β-FeSi 2 thin films. In this method, Fe is evaporated by E-gun and a few percents of Fe atoms are ionized. We have investigated influences of the ion content and the accelerating voltage of Fe ions on the structural properties of β-FeSi 2 films deposited on Si substrates. It was confirmed that β-FeSi 2 can be formed on Si(1 0 0) substrate by PIVD even at substrate temperature as low as 350, while FeSi by the conventional vacuum deposition. It was concluded that the influence of Fe ions on preferential orientation of β-FeSi 2 depends strongly on the content and the acceleration energy of ions.

XAFS Studies of Fe Doped PhTiO3 Nanoparticles

International Nuclear Information System (INIS)

Shibata, Tomohiro; Chattopadhyay, Soma; Lin Bin; Palkar, V. R.

2007-01-01

Fe K and Ti K edge XAFS studies are reported on Fe doped PbTiO3 nanoparticles down to the 10 nm size. Fe forms Fe3+ ions and substitute for Ti4+ ions. For 18 nm nanoparticles, the Fe and Ti environment is found to be quite different. For PbFe0.5Ti0.5O3, locally the structure remains distorted from bulk to 10 nm size although the average structure changes

Impact of Ion Bombardment on the Structure and Magnetic Properties of Fe78Si13B9 Amorphous Alloy

Science.gov (United States)

Wu, Yingwei; Peng, Kun

2018-06-01

Amorphous Fe78Si13B9 alloy ribbons were bombarded by ion beams with different incident angles ( θ ). The evolution of the microstructure and magnetic properties of ribbons caused by ion beam bombardment was investigated by x-ray diffraction, transmission electron microscope and vibrating sample magnetometer analysis. Low-incident-angle bombardment led to atomic migration in the short range, and high-incident-angle bombardment resulted in the crystallization of amorphous alloys. Ion bombardment induces magnetic anisotropy and affects magnetic properties. The effective magnetic anisotropy was determined by applying the law of approach to saturation, and it increased with the increase of the ion bombardment angle. The introduction of effective magnetic anisotropy will reduce the permeability and increase the relaxation frequency. Excellent high-frequency magnetic properties can be obtained by selecting suitable ion bombardment parameters.

Li2FeSiO4 nanorod as high stability electrode for lithium-ion batteries

International Nuclear Information System (INIS)

Hsu, Chun-Han; Shen, Yu-Wen; Chien, Li-Hsuan; Kuo, Ping-Lin

2015-01-01

Li 2 FeSiO 4 (LFS) nanorods, with a diameter of 80–100 nm and length of 0.8–1.0 μm, were synthesized successfully from a mixture of LiOH, FeSO 4 , and SiO 2 nanoparticles via a simple hydrothermal process. The secondary structure with micro-sized bundles of nanorods was developed with high crystallinity under the hydrothermal condition of 180 °C for 72 h. Then, sucrose, as carbon source, was coated and carbonized on the surface of the LFS nanorods to fabricate LFS/C nanorod composite. The resulting LFS/C nanorod composite was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and surface area measurements. When used as the cathode materials for lithium-ion battery, the electrochemical performance of the LFS/C nanorod material delivers discharge capacities of 156 mAh g −1 in the voltage window of 1.8−4.7 V and also demonstrates good cycle stability when it is cycled between 1.8 and 4.1 V. In short, superior electrochemical properties could be caused by the short lithium-ion diffusion path of its nanorod structure

Study of ion beam sputtered Fe/Si interfaces as a function of Si layer thickness

Science.gov (United States)

Kumar, Anil; Brajpuriya, Ranjeet; Singh, Priti

2018-01-01

The exchange interaction in metal/semiconductor interfaces is far from being completely understood. Therefore, in this paper, we have investigated the nature of silicon on the Fe interface in the ion beam deposited Fe/Si/Fe trilayers keeping the thickness of the Fe layers fixed at 3 nm and varying the thickness of the silicon sandwich layer from 1.5 nm to 4 nm. Grazing incidence x-ray diffraction and atomic force microscopy techniques were used, respectively, to study the structural and morphological changes in the deposited films as a function of layer thickness. The structural studies show silicide formation at the interfaces during deposition and better crystalline structure of Fe layers at a lower spacer layer thickness. The magnetization behavior was investigated using magneto-optical Kerr effect, which clearly shows that coupling between the ferromagnetic layers is highly influenced by the semiconductor spacer layer thickness. A strong antiferromagnetic coupling was observed for a value of tSi = 2.5 nm but above this value an unexpected behavior of hysteresis loop (step like) with two coercivity values is recorded. For spacer layer thickness greater than 2.5 nm, an elemental amorphous Si layer starts to appear in the spacer layer in addition to the silicide layer at the interfaces. It is observed that in the trilayer structure, Fe layers consist of various stacks, viz., Si doped Fe layers, ferromagnetic silicide layer, and nonmagnetic silicide layer at the interfaces. The two phase hysteresis loop is explained on the basis of magnetization reversal of two ferromagnetic layers, independent of each other, with different coercivities. X-ray photo electron spectroscopy technique was also used to study interfaces characteristics as a function of tSi.

Synthesis and characterization of TiO2 photocatalyst doped by transition metal ions (Fe3+, Cr3+ and V5+)

International Nuclear Information System (INIS)

Tuan Vu, Anh; Linh Bui, Thi Hai; Cuong Tran, Manh; Phuong Dang, Tuyet; Hoa Tran, Thi Kim; Tuan Nguyen, Quoc

2010-01-01

Nano TiO 2 was synthesized by the hydrothermal method. The sample was doped with transition metal ions (V, Cr and Fe) and non-metal (N). Doped TiO 2 samples were characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and UV-Vis diffuse reflectance spectroscopy (UV-Vis). Photocatalytic activity in the mineralization of xylene (vapor phase), methylene blue and active dyer PR (liquid phase) was tested. In comparison with non-doped TiO 2 , V-, Cr-, Fe-doped TiO 2 and N-doped TiO 2 samples exhibited much higher photocatalytic activity using visible light instead of UV

Fe II/Fe III mixed-valence state induced by Li-insertion into the metal-organic-framework Mil53(Fe): A DFT+U study

Science.gov (United States)

Combelles, C.; Ben Yahia, M.; Pedesseau, L.; Doublet, M.-L.

The iron-based metal-organic-framework MIL53(Fe) has recently been tested as a cathode materials for Li-Ion batteries, leading to promising cycling life and rate capability. Despite a poor capacity of 70 mAh g -1 associated with the exchange of almost 0.5Li/Fe, this result is the first evidence of a reversible lithium insertion never observed in a MOF system. In the present study, the MIL53(Fe) redox mechanism is investigated through first-principles DFT+U calculations. The results show that MIL53(Fe) is a weak antiferromagnetic charge transfer insulator at T = 0 K, with iron ions in the high-spin S = 5/2 state. Its reactivity vs elemental lithium is then investigated as a function of lithium composition and distribution over the most probable Li-sites of the MOF structure. The redox mechanism is fully interpreted as a two-step insertion/conversion mechanism, associated with the stabilization of the Fe 3+/Fe 2+ mixed-valence state prior to the complete decomposition of the inorganic-organic interactions within the porous MOF architecture.

Simulated space radiation-induced mutants in the mouse kidney display widespread genomic change.

Directory of Open Access Journals (Sweden)

Mitchell S Turker

Full Text Available Exposure to a small number of high-energy heavy charged particles (HZE ions, as found in the deep space environment, could significantly affect astronaut health following prolonged periods of space travel if these ions induce mutations and related cancers. In this study, we used an in vivo mutagenesis assay to define the mutagenic effects of accelerated 56Fe ions (1 GeV/amu, 151 keV/μm in the mouse kidney epithelium exposed to doses ranging from 0.25 to 2.0 Gy. These doses represent fluences ranging from 1 to 8 particle traversals per cell nucleus. The Aprt locus, located on chromosome 8, was used to select induced and spontaneous mutants. To fully define the mutagenic effects, we used multiple endpoints including mutant frequencies, mutation spectrum for chromosome 8, translocations involving chromosome 8, and mutations affecting non-selected chromosomes. The results demonstrate mutagenic effects that often affect multiple chromosomes for all Fe ion doses tested. For comparison with the most abundant sparsely ionizing particle found in space, we also examined the mutagenic effects of high-energy protons (1 GeV, 0.24 keV/μm at 0.5 and 1.0 Gy. Similar doses of protons were not as mutagenic as Fe ions for many assays, though genomic effects were detected in Aprt mutants at these doses. Considered as a whole, the data demonstrate that Fe ions are highly mutagenic at the low doses and fluences of relevance to human spaceflight, and that cells with considerable genomic mutations are readily induced by these exposures and persist in the kidney epithelium. The level of genomic change produced by low fluence exposure to heavy ions is reminiscent of the extensive rearrangements seen in tumor genomes suggesting a potential initiation step in radiation carcinogenesis.

Simulated space radiation-induced mutants in the mouse kidney display widespread genomic change.

Science.gov (United States)

Turker, Mitchell S; Grygoryev, Dmytro; Lasarev, Michael; Ohlrich, Anna; Rwatambuga, Furaha A; Johnson, Sorrel; Dan, Cristian; Eckelmann, Bradley; Hryciw, Gwen; Mao, Jian-Hua; Snijders, Antoine M; Gauny, Stacey; Kronenberg, Amy

2017-01-01

Exposure to a small number of high-energy heavy charged particles (HZE ions), as found in the deep space environment, could significantly affect astronaut health following prolonged periods of space travel if these ions induce mutations and related cancers. In this study, we used an in vivo mutagenesis assay to define the mutagenic effects of accelerated 56Fe ions (1 GeV/amu, 151 keV/μm) in the mouse kidney epithelium exposed to doses ranging from 0.25 to 2.0 Gy. These doses represent fluences ranging from 1 to 8 particle traversals per cell nucleus. The Aprt locus, located on chromosome 8, was used to select induced and spontaneous mutants. To fully define the mutagenic effects, we used multiple endpoints including mutant frequencies, mutation spectrum for chromosome 8, translocations involving chromosome 8, and mutations affecting non-selected chromosomes. The results demonstrate mutagenic effects that often affect multiple chromosomes for all Fe ion doses tested. For comparison with the most abundant sparsely ionizing particle found in space, we also examined the mutagenic effects of high-energy protons (1 GeV, 0.24 keV/μm) at 0.5 and 1.0 Gy. Similar doses of protons were not as mutagenic as Fe ions for many assays, though genomic effects were detected in Aprt mutants at these doses. Considered as a whole, the data demonstrate that Fe ions are highly mutagenic at the low doses and fluences of relevance to human spaceflight, and that cells with considerable genomic mutations are readily induced by these exposures and persist in the kidney epithelium. The level of genomic change produced by low fluence exposure to heavy ions is reminiscent of the extensive rearrangements seen in tumor genomes suggesting a potential initiation step in radiation carcinogenesis.

One-pot hydrothermal synthesis of hollow Fe3O4 microspheres assembled with nanoparticles for lithium-ion battery anodes

DEFF Research Database (Denmark)

Liu, Yanguo; Wang, Xiaoliang; Ma, Wuming

2016-01-01

Hollow Fe3O4 microspheres assembled with nanoparticles were successfully synthesized without the addition of any templates or subsequent treatments. When used as the anode materials for lithium-ion battery (LIB), the products showed good lithium storage properties, demonstrating their promising...

Synthesis of hierarchical conductive C/LiFePO_4/carbon nanotubes composite with less antisite defects for high power lithium-ion batteries

International Nuclear Information System (INIS)

Song, Jianjun; Shao, Guangjie; Ma, Zhipeng; Wang, Guiling; Yang, Jing

2015-01-01

Graphical abstract: The hierarchical conductive C/LiFePO4/CNTs composite with less antisite defects is synthesized by a modified solvothemal process and delivers superior electrochemical performance with high rate capability and good capacity retention. - Abstract: The low electronic conductivity and Li ion diffusion ability are two major obstacles to realize its wide application for LiFePO_4 materials. The material with hierarchical conductive structure and lower antisite defects concentration can effectively enhance the electronic conductivity and Li ion diffusion ability. We firstly report here a modified solvothemal process for the fabrication of hierarchical conductive C/LiFePO_4/CNTs composite with less antisite defects. It is found that the modified solvothemal process is facilitated to decrease Fe_L_i antisite defects and enhance the electronic continuity between LFP and CNTs. In favor of its unique properties, the C/LFP/CNTs composites can deliver superior rate capability and cycling stability. Remarkably, even at a high rate of 20C (3400 mA g"−"1), a high initial discharge capacity of 91.6 mAh g"−"1 and good cycle retention of 95% with almost 100% coulombic efficiency are still obtained after 100 cycles.

Fragmentation and reactivity of energy-selected ferrocenium ions

International Nuclear Information System (INIS)

Mestdagh, H.; Dutuit, O.; Heninger, M.; Thissen, R.; Alcaraz, C.

2002-01-01

In this study, results concerning the discussion of state-selected ferrocenium ions (c-C 5 H 5 ) 2 Fe + commonly called Cp 2 Fe + , as well as their reactions with methanol and ethanol are presented. Parent ions Cp 2 Fe + were produced by vacuumultraviolett (VUV) photoionization of neutral ferrocene using synchrotron radiation, and selected in internal energy by threshold photoelectron-photoion coincidences. The apparatus is divided into three differentially pumped regions: the source, the reaction and the detection zones. In source, state-selected parent ions are formed and can be selected in mass by a first quadrupole filter. State-selected ions are then injected in the second zone which is a RF octopole ion guide where reaction product ions are mass analyzed by a second quadrupole filter and detected by microchannelplates. In addition, the long flight time in the octopoles (several hundreds of microseconds) allows studying long-lived metastable ions. Total mass spectra were recorded at different photon energies, in addition to the main CpFe + and Fe + fragments, several minor fragments were detected such as C 10 H 10 + which reflects the formation of a C-C bond between the two Cp ligands. Losses of CH 3 , C 2 H 2 and C-4H 4 also indicate that important structure rearrangements take place before cleavage. The appearance energies of each mass-selected fragment ion were measured by recording fragment ion yields as a function of photon energy. Surprisingly, all fragments were found to have the same energy onset, i.e. 13.2 eV photon energy, except for C 3 H 3 Fe + (m/z 95). For Fe + ions, a sharp increase was observed at 17 eV, above the thermochemical onset of Fe + + 2 Cp. The 13.2 eV appearance energy of Fe + is thus assigned to the formation of Fe - + C 10 H 10 . The reactivity of ferrocenium ion with methanol and ethanol was investigated as a function of photon energy. While no reaction occurs at lower photon energies, several reaction products appear at 13.0 e

Solvothermal synthesis of Mg-doped Li2FeSiO4/C nanocomposite cathode materials for lithium-ion batteries

Science.gov (United States)

Kumar, Ajay; Jayakumar, O. D.; Naik, V. M.; Nazri, G. A.; Naik, R.

Lithium transition metal orthosilicates, such as Li2FeSiO4 and Li2MnSiO4, as cathode material have attracted much attention lately due to their high theoretical capacity ( 330 mAh/g), low cost, and environmental friendliness. However, they suffer from poor electronic conductivity and slow lithium ion diffusion in the solid phase. Several cation-doped orthosilicates have been studied to improve their electrochemical performance. We have synthesized partially Mg-substituted Li2Mgx Fe1-x SiO4-C, (x = 0.0, 0.01, 0.02, and 0.04) nano-composites by solvothermal method followed by annealing at 600oC in argon flow. The structure and morphology of the composites were characterized by XRD, SEM and TEM. The surface area and pore size distribution were measured by using N2 adsorption/desorption curves. The electrochemical performance of the Li2MgxFe1-x SiO4-C composites was evaluated by Galvanostatic cycling against metallic lithium anode, electrochemical impedance spectroscopy, and cyclic voltammetry. Li2Mg0.01Fe0.99SiO4-C sample shows a capacity of 278 mAh/g (at C/30 rate in the 1.5-4.6 V voltage window) with an excellent rate capability and stability, compared to the other samples. We attribute this observation to its higher surface area, enhanced electronic conductivity and higher lithium ion diffusion coefficient.

Monodisperse porous LiFePO4/C microspheres derived by microwave-assisted hydrothermal process combined with carbothermal reduction for high power lithium-ion batteries

Science.gov (United States)

Chen, Rongrong; Wu, Yixiong; Kong, Xiang Yang

2014-07-01

A microwave-assisted hydrothermal approach combined with carbothermal reduction has been developed to synthesize monodisperse porous LiFePO4/C microspheres, which possess the diameter range of 1.0-1.5 μm, high tap density of ∼1.3 g cm-3, and mesoporous characteristic with Brunauer-Emmett-Teller (BET) surface area of 30.6 m2 g-1. The obtained microspheres show meatball-like morphology aggregated by the carbon-coated LiFePO4 nanoparticles. The electrochemical impedance spectra (EIS) results indicate that carbon coating can effectively enhance both of the electronic and ionic conductivities for LiFePO4/C microspheres. The Li-ion diffusion coefficient of the LiFePO4/C microspheres calculated from the cyclic voltammetry (CV) curves is ∼6.25 × 10-9 cm2 s-1. The electrochemical performance can achieve about 100 and 90 mAh g-1 at 5C and 10C charge/discharge rates, respectively. As cathode material, the as-prepared LiFePO4/C microspheres show excellent rate capability and cycle stability, promising for high power lithium-ion batteries.

Velocity dependence of enhanced dynamic hyperfine field for Pd ions swiftly recoiling in magnetized Fe

International Nuclear Information System (INIS)

Stuchbery, A.E.; Ryan, G.C.; Bolotin, H.H.; Sie, S.H.

1980-01-01

The velocity-dependence of the magnitude of the enchanced dynamic hyperfine magnetic field (EDF) manifest at nuclei of 108 Pd ions swiftly recoiling through thin magnetized Fe has been investigated at ion velocities higher than have heretofore been examined for the heavier nuclides (i.e., at initial recoil velocities (v/Zv 0 )=0.090 and 0.160, v 0 =c/137). These results for 108 Pd, when taken in conjunction with those of prior similar measurements for 106 Pd at lower velocities, and fitted to a velocity dependence for the EDF, give for the Pd isotopes over the extended velocity range 1.74 0 )<=7.02, p=0.41+-0.15; a result incompatible with previous attributions of a linear velocity dependence for the field

Calculation of the substitutional fraction of ion-implanted He in an α-Fe target

Science.gov (United States)

Erhart, Paul; Marian, Jaime

2011-07-01

Ion-implantation is a useful technique to study irradiation damage in nuclear materials. To study He effects in nuclear fusion conditions, He is co-implanted with damage ions to reproduce the correct He/dpa ratios in the desired or available depth range. However, the short-term fate of these He ions, i.e. over the time scales of their own collisional phase, has not been yet unequivocally established. Here we present a computational study of the short-term evolution of He implantation in an Fe substrate at 700 K to approximate the conditions encountered in dual ion-implantation studies in ferritic materials. Using a combination of SRIM, molecular dynamics and kinetic Monte Carlo (kMC), we calculate the fraction of He atoms that end up in substitutional sites shortly after implantation, i.e. before they contribute to long-term microstructural evolution. We find that fractions of at most 3% should be expected for most implantation studies. Additionally, to inform the kMC calculations, we carry out an exhaustive calculation of interstitial He migration energy barriers in the vicinity of matrix vacancies and find that they vary from approximately 20-60 meV depending on the separation and orientation of the He-vacancy pair.

Calculation of the substitutional fraction of ion-implanted He in an α-Fe target

International Nuclear Information System (INIS)

Erhart, Paul; Marian, Jaime

2011-01-01

Ion-implantation is a useful technique to study irradiation damage in nuclear materials. To study He effects in nuclear fusion conditions, He is co-implanted with damage ions to reproduce the correct He/dpa ratios in the desired or available depth range. However, the short-term fate of these He ions, i.e. over the time scales of their own collisional phase, has not been yet unequivocally established. Here we present a computational study of the short-term evolution of He implantation in an Fe substrate at 700 K to approximate the conditions encountered in dual ion-implantation studies in ferritic materials. Using a combination of SRIM, molecular dynamics and kinetic Monte Carlo (kMC), we calculate the fraction of He atoms that end up in substitutional sites shortly after implantation, i.e. before they contribute to long-term microstructural evolution. We find that fractions of at most 3% should be expected for most implantation studies. Additionally, to inform the kMC calculations, we carry out an exhaustive calculation of interstitial He migration energy barriers in the vicinity of matrix vacancies and find that they vary from approximately 20-60 meV depending on the separation and orientation of the He-vacancy pair.

Mapping Structure-Composition-Property Relationships in V- and Fe-Doped LiMnPO4 Cathodes for Lithium-Ion Batteries.

Science.gov (United States)

Johnson, Ian D; Loveridge, Melanie; Bhagat, Rohit; Darr, Jawwad A

2016-11-14

A series of LiMn 1-x-y Fe x V y PO 4 (LMFVP) nanomaterials have been synthesized using a pilot-scale continuous hydrothermal synthesis process (CHFS) and evaluated as high voltage cathodes in Li-ion batteries at a production rate of 0.25 kg h -1 . The rapid synthesis and screening approach has allowed the specific capacity of the high Mn content olivines to be optimized, particularly at high discharge rates. Consistent and gradual changes in the structure and performance are observed across the compositional region under investigation; the doping of Fe at 20 at% (with respect to Mn) into lithium manganese phosphate, rather than V or indeed codoping of Fe and V, gives the best balance of high capacity and high rate performance.

Studies on the effects of cosmic HZE-particles on different biological systems in the Biostack experiments I and II flown on board of Apollo 16 and 17

International Nuclear Information System (INIS)

Bucker, H.; Horneck, G.

1975-01-01

The Biostack experiments are described and the effects of cosmic HZE-particles on different biological systems are discussed. The biological systems contained in the experimental packages include spores of Bacillus subtilis, cysts of Colpoda cucullus, seeds of Arabidopsis thaliana, radiculae of Vicia faba, and eggs of Artemia solina, Tribolium castaneum, and Carausius moresus. The physical characteristics of the particles are given and the implications for manned spaceflight are discussed

Implantation of Fe ions into aluminium fast cooled tapes; Vliyanie bombardirovki c uskorennymi do 70 keV jonami na structuru i svoistva alyuminievogo splava

Energy Technology Data Exchange (ETDEWEB)

Dimova, V; Danailov, D; Markov, T; Zlateva, G [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. po Metaloznanie i Tekhnologiya na Metalite; Angelov, Kh [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. za Yadrena Izsledvaniya i Yadrena Energetika

1996-12-31

Aluminium alloy containing 1% Zn is investigated as a material for fusion reactor first wall. The effect of 60 keV Fe ion implantation at a dose 10{sup 16}-10{sup 17} cm{sup -2} on the microstructure and properties of 50 {mu}m thick tapes has been investigated. It is found that implantation affects mainly the surface at the crystallite boundaries. An over-equilibrium solubility of Fe in the alloy Al-1% Zn has been established. Fe ions move by diffusion along the grain boundaries and contribute to increased magnetic properties after annealing at 250{sup o} C for at least 2 hours. Quasi-amorphous implanted alloy containing ferromagnetic atoms has been detected. The estimated Curie temperature has been estimated to 540 {sup o} C, which is typical for strongly diluted solid solutions. 3 refs., 6 figs.

The preparation of Zn-ferrite epitaxial thin film from epitaxial Fe3O4:ZnO multilayers by ion beam sputtering deposition

International Nuclear Information System (INIS)

Su, Hui-Chia; Dai, Jeng-Yi; Liao, Yen-Fa; Wu, Yu-Han; Huang, J.C.A.; Lee, Chih-Hao

2010-01-01

A new method to grow a well-ordered epitaxial ZnFe 2 O 4 thin film on Al 2 O 3 (0001) substrate is described in this work. The samples were made by annealing the ZnO/Fe 3 O 4 multilayer which was grown with low energy ion beam sputtering deposition. Both the Fe 3 O 4 and ZnO layers were found grown epitaxially at low temperature and an epitaxial ZnFe 2 O 4 thin film was formed after annealing at 1000 o C. X-ray diffraction shows the ZnFe 2 O 4 film is grown with an orientation of ZnFe 2 O 4 (111)//Al 2 O 3 (0001) and ZnFe 2 O 4 (1-10)//Al 2 O 3 (11-20). X-ray absorption spectroscopy studies show that Zn 2+ atoms replace the tetrahedral Fe 2+ atoms in Fe 3 O 4 during the annealing. The magnetic properties measured by vibrating sample magnetometer show that the saturation magnetization of ZnFe 2 O 4 grown from ZnO/Fe 3 O 4 multilayer reaches the bulk value after the annealing process.

In-situ generation of Li2FeSiO4/C nanocomposite as cathode material for lithium ion battery

International Nuclear Information System (INIS)

Yi, Jin; Hou, Meng-yan; Bao, Hong-liang; Wang, Cong-xiao; Wang, Jian-qiang; Xia, Yong-yao

2014-01-01

Highlights: • A Li 2 FeSiO 4 /C nanocomposite is prepared via thermal vapor deposition technology. • The Li 2 FeSiO 4 /C nanocomposite is free from impurity and coated with carbon layer. • The Li 2 FeSiO 4 /C nanocomposite exhibits good rate capability and cycling stability. • Lithium benzoate serves as both lithium and carbon sources. - Abstract: A Li 2 FeSiO 4 /C nanocomposite is prepared via solvothermal method in combination with carbon coating technology. The as-prepared Li 2 FeSiO 4 /C nanocomposite is a single phase Li 2 FeSiO 4 with nano-tickness coated carbon layer and connected by the mutual cross-linked carbon conductive matrix. As cathode material for lithium ion battery, the composite delivers a discharge capacity of 154 mAh g −1 at 1 C and exhibits good rate capability with a discharge capacity of 106 mAh g −1 at the rate of 10 C, which is ascribed to the small particle size and enhanced electronic conductivity using carbon coating technology. The as-prepared Li 2 FeSiO 4 /C nanocomposite also behaves a good cycling stability with capacity retention of over 100 cycles

Unique Fe2P Nanoparticles Enveloped in Sandwichlike Graphited Carbon Sheets as Excellent Hydrogen Evolution Reaction Catalyst and Lithium-Ion Battery Anode.

Science.gov (United States)

Zhang, Yan; Zhang, Huijuan; Feng, Yangyang; Liu, Li; Wang, Yu

2015-12-09

The novel Fe2P nanoparticles encapsulated in sandwichlike graphited carbon envelope nanocomposite (Fe2P/GCS) that can be first applied in hydrogen evolution reaction (HER) as well as lithium-ion batteries (LIBs) has been designed and fabricated. The unique sandwiched Fe2P/GCS is characterized with several prominent merits, including large specific surface area, nanoporous structure, excellent electronic conductivity, enhanced structural integrity and so on. All of these endow the Fe2P/GCS with brilliant electrochemical performance. When used as a HER electrocatalyst in acidic media, the harvested Fe2P/GCS demonstrates low onset overpotential and Tafel slope as well as particularly outstanding durability. Moreover, as an anode material for LIBs, the sandwiched Fe2P/GCS presents high specific capacity and excellent cyclability and rate capability. As a consequence, the acquired Fe2P/GCS is a promising material for energy applications, especially HER and LIBs.

Electrochemical impedance characterization of FeSn2 electrodes for Li-ion batteries

International Nuclear Information System (INIS)

Chamas, M.; Lippens, P-E.; Jumas, J-C.; Hassoun, J.; Panero, S.; Scrosati, B.

2011-01-01

Highlights: → In this paper we study a tin based, FeSn 2 , high capacity lithium-alloying electrode. → The electrochemical performance of this electrode in lithium batteries is remarkably influenced by the current rate. → This aspect is investigated by electrochemical techniques such as galvanostatic cycling and impedance spectroscopy. → The results demonstrated that the good electrochemical behavior of the electrode at the higher currents is due to the formation of a stable solid electrolyte interphase (SEI) film. - Abstract: This work reports the electrochemical characterization of a micro-scale FeSn 2 electrode in a lithium battery. The electrode is proposed as anode material for advanced lithium ion batteries due to its characteristics of high capacity (500 mAh g -1 ) and low working voltage (0.6 V vs. Li). The electrochemical alloying process is studied by cyclic voltammetry and galvanostatic cycling while the interfacial properties are investigated by electrochemical impedance spectroscopy. The impedance measurements in combination with the galvanostatic cycling tests reveal relatively low overall impedance values and good electrochemical performance for the electrode, both in terms of delivered capacity and cycling stability, even at the higher C-rate regimes.

Carbon-covered Fe_3O_4 hollow cubic hierarchical porous composite as the anode material for lithium-ion batteries

International Nuclear Information System (INIS)

Chen, Shouhui; Zhou, Rihui; Chen, Yaqin; Fu, Yuanyuan; Li, Ping; Song, Yonghai; Wang, Li

2017-01-01

In this work, Prussian blue nanocrystals, a kind of cubic metal-organic frameworks, was firstly covered by a uniform layer of resorcinol-formaldehyde (RF) resin, and then followed with heat treatment at different pyrolysis temperatures. The effects of pyrolysis temperature on the morphologies, phase, pore size, and electrochemical performance of the pyrolysis products were studied in this work. The composite generated at 600 "∘C, FexC600, was a hollow cubic composite of Fe_3O_4 covered by a thin RF-derived carbon layer. The carbon layer on FexC600 was a robust and conductive protective layer, which can accommodate Fe_3O_4 NPs and withstand the huge volume change of Fe_3O_4 during the process of discharge and charge. When used as anodes for lithium-ion batteries, FexC600 showed excellent electrochemical performance. It delivered a discharge capacity of 1126 mAh g"−"1 with a coulombic efficiency of 98.8% at the current density of 100 mA g"−"1 after 100 times discharge/charge cycling. It even delivered a capacity of 492 mAh g"−"1 at the current density of 500 mA g"−"1. This cubic hollow composite would be a promising alternative anode material for lithium-ion batteries.

Core-shell LiFePO4 /carbon-coated reduced graphene oxide hybrids for high-power lithium-ion battery cathodes.

Science.gov (United States)

Ha, Sung Hoon; Lee, Yun Jung

2015-01-26

Core-shell carbon-coated LiFePO4 nanoparticles were hybridized with reduced graphene (rGO) for high-power lithium-ion battery cathodes. Spontaneous aggregation of hydrophobic graphene in aqueous solutions during the formation of composite materials was precluded by employing hydrophilic graphene oxide (GO) as starting templates. The fabrication of true nanoscale carbon-coated LiFePO4 -rGO (LFP/C-rGO) hybrids were ascribed to three factors: 1) In-situ polymerization of polypyrrole for constrained nanoparticle synthesis of LiFePO4 , 2) enhanced dispersion of conducting 2D networks endowed by colloidal stability of GO, and 3) intimate contact between active materials and rGO. The importance of conducting template dispersion was demonstrated by contrasting LFP/C-rGO hybrids with LFP/C-rGO composites in which agglomerated rGO solution was used as the starting templates. The fabricated hybrid cathodes showed superior rate capability and cyclability with rates from 0.1 to 60 C. This study demonstrated the synergistic combination of nanosizing with efficient conducting templates to afford facile Li(+) ion and electron transport for high power applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of Fe3O4 cluster microspheres/graphene aerogels composite as anode for high-performance lithium ion battery

Science.gov (United States)

Zhou, Shuai; Zhou, Yu; Jiang, Wei; Guo, Huajun; Wang, Zhixing; Li, Xinhai

2018-05-01

Iron oxides are considered as attractive electrode materials because of their capability of lithium storage, but their poor conductivity and large volume expansion lead to unsatisfactory cycling stability. We designed and synthesized a novel Fe3O4 cluster microspheres/Graphene aerogels composite (Fe3O4/GAs), where Fe3O4 nanoparticles were assembled into cluster microspheres and then embedded in 3D graphene aerogels framework. In the spheres, the sufficient free space between Fe3O4 nanoparticles could accommodate the volume change during cycling process. Graphene aerogel works as flexible and conductive matrix, which can not only significantly increase the mechanical stress, but also further improve the storage properties. The Fe3O4/GAs composite as an anode material exhibits high reversible capability and excellent cyclic capacity for lithium ion batteries (LIBs). A reversible capability of 650 mAh g-1 after 500 cycles at a current density of 1 A g-1 can be maintained. The superior storage capabilities of the composites make them potential anode materials for LIBs.

Fe and O EELS Studies of Ion Irradiated Murchison CM2 Carbonaceous Chondrite Matrix

Science.gov (United States)

Keller, L. P.; Christofferson, R.; Dukes, C. A.; Baragiola, R. A.; Rahman, Z.

2015-01-01

Introduction: The physical and chemical response of hydrated carbonaceous chondrite materials to space weathering processes is poorly understood. Improving this understanding is a key part of establishing how regoliths on primitive carbonaceous asteroids respond to space weathering processes, knowledge that supports future sample return missions (Hayabusa 2 and OSIRISREx) that are targeting objects of this type. We previously reported on He+ irradiation of Murchison matrix and showed that the irradiation resulted in amorphization of the matrix phyllosilicates, loss of OH, and surface vesiculation. Here, we report electron energy-loss spectroscopy (EELS) measurements of the irradiated material with emphasis on the Fe and O speciation. Sample and Methods: A polished thin section of the Murchison CM2 carbonaceous chondrite was irradiated with 4 kilovolts He(+) (normal incidence) to a total dose of 1 x 10(exp 18) He(+) per square centimeter. We extracted thin sections from both irradiated and unirradiated regions in matrix using focused ion beam (FIB) techniques with electron beam deposition for the protective carbon strap to minimize surface damage artifacts from the FIB milling. The FIB sections were analyzed using a JEOL 2500SE scanning and transmission electron microscope (STEM) equipped with a Gatan Tridiem imaging filter. EELS spectra were collected from 50 nanometer diameter regions with an energy resolution of 0.7 electronvolts FWHM at the zero loss. EELS spectra were collected at low electron doses to minimize possible artifacts from electron-beam irradiation damage. Results and Discussion: Fe L (sub 2,3) EELS spectra from matrix phyllosilicates in CM chondrites show mixed Fe(2+)/Fe(3+) oxidation states with Fe(3+)/Sigma Fe approximately 0.5. Fe L(sub 2,3) spectra from the irradiated/ amorphized matrix phyllosilicates show higher Fe(2+)/Fe(3+) ratios compared to spectra obtained from pristine material at depths beyond the implantation/amorphization layer. We

Magnetism mediated by a majority of [Fe³⁺ + VO²⁻] complexes in Fe-doped CeO₂ nanoparticles.

Science.gov (United States)

Paidi, V K; Ferreira, N S; Goltz, D; van Lierop, J

2015-08-26

We examine the role of Fe(3+) and vacancies (V(O)) on the magnetism of Fe-doped CeO2 nanoparticles. Magnetic nanoparticles of Ce(100-x)Fe(x)O2 (x  =  0, 0.26, 1.82, 2.64, 5.26, 6.91, and 7.22) were prepared by a co-precipitation method, and their structural, compositional and magnetic properties were investigated. The CeO2 nanoparticles had a mixed valance of Ce(4+) and Ce(3+) ions, and doping introduced Fe(3+) ions. The decrease in Ce(3+) and increase in Fe(3+) concentrations indicated the presence of more [Fe(3+) + V(O)(2-)] complexes with Fe loading in the particles. Charge neutralization, Fe(3+) + V(O)(2-) + 2Ce(4+) ↔ 2Ce(3+) + Fe(3+), identified the impact of V(O) on the magnetism, where our results suggest that the Fe-doped CeO2 nanoparticle magnetism is mediated by a majority of [Fe(3+) + V(O)(2-)]-Ce(3+) -[Fe(3+) + V(O)(2-)] complexes.

Microstructure of Au-ion irradiated 316L and FeNiCr austenitic stainless steels

Energy Technology Data Exchange (ETDEWEB)

Jublot-Leclerc, S., E-mail: stephanie.jublot-leclerc@csnsm.in2p3.fr [CSNSM, Univ Paris-Sud, CNRS, Université Paris Saclay, 91405 Orsay (France); Li, X. [CSNSM, Univ Paris-Sud, CNRS, Université Paris Saclay, 91405 Orsay (France); Legras, L.; Lescoat, M.-L. [EDF R& D, Groupe Métallurgie, Les Renardières, 77818 Moret sur Loing (France); Fortuna, F.; Gentils, A. [CSNSM, Univ Paris-Sud, CNRS, Université Paris Saclay, 91405 Orsay (France)

2016-11-15

Thin foils of 316L were irradiated in situ in a Transmission Electron Microscope with 4 MeV Au ions at 450 °C and 550 °C. Similar irradiations were performed at 450 °C in FeNiCr. The void and dislocation microstructure of 316L is found to depend strongly on temperature. At 450 °C, a dense network of dislocation lines is observed in situ to grow from black dot defects by absorption of other black dots and interstitial clusters whilst no Frank loops are detected. At 550 °C, no such network is observed but large Frank loops and perfect loops whose sudden appearance is concomitant with a strong increase in void density as a result of a strong coupling between voids and dislocations. Moreover, differences in both alloys microstructure show the major role played by the minor constituents of 316L, increasing the stacking fault formation energy, and possibly leading to significant differences in swelling behaviour. - Highlights: • 316L and FeNiCr were ion irradiated in situ in a TEM at elevated temperature. • The minor constituents of 316L play a major role in the resulting microstructure. • A dense network of dislocations develops in both alloys from black dot defects. • The nucleation and growth of voids and dislocations are strongly correlated. • The Frank loop mean size saturates at similar dpa values as in neutron irradiation.

3D Fe{sub 2}(MoO{sub 4}){sub 3} microspheres with nanosheet constituents as high-capacity anode materials for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Zheng, Hao; Wang, Shiqiang [Hubei University, Key Laboratory for Synthesis and Applications of Organic Functional Molecules (China); Wang, Jiazhao; Wang, Jun [University of Wollongong, Institute for Superconducting and Electronic Materials (Australia); Li, Lin; Yang, Yun; Feng, Chuanqi, E-mail: cfeng@hubu.edu.cn [Hubei University, Key Laboratory for Synthesis and Applications of Organic Functional Molecules (China); Sun, Ziqi, E-mail: ziqi.sun@qut.edu.au [Queensland University of Technology, School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty (Australia)

2015-11-15

Three-dimensional (3D) Fe{sub 2}(MoO{sub 4}){sub 3} microspheres with ultrathin nanosheet constituents are first synthesized as anode materials for the lithium-ion battery. It is interesting that the single-crystalline nanosheets allow rapid electron/ion transport on the inside, and the high porosity ensures fast diffusion of liquid electrolyte in energy storage applications. The electrochemical properties of Fe{sub 2}(MoO{sub 4}){sub 3} as anode demonstrates that 3D Fe{sub 2}(MoO{sub 4}){sub 3} microspheres deliver an initial capacity of 1855 mAh/g at a current density of 100 mA/g. Particularly, when the current density is increased to 800 mA/g, the reversible capacity of Fe{sub 2}(MoO{sub 4}){sub 3} anode still arrived at 456 mAh/g over 50 cycles. The large and reversible capacities and stable charge–discharge cycling performance indicate that Fe{sub 2}(MoO{sub 4}){sub 3} is a promising anode material for lithium battery applications.Graphical abstractThe electrochemical properties of Fe{sub 2}(MoO{sub 4}){sub 3} as anode demonstrates that 3D Fe{sub 2}(MoO{sub 4}){sub 3} microspheres delivered an initial capacity of 1855 mAh/g at a current density of 100 mA/g. When the current density was increased to 800 mA/g, the Fe{sub 2}(MoO{sub 4}){sub 3} still behaved high reversible capacity and good cycle performance.

Competition of dipositive metal ions for Fe (III) binding sites in chelation therapy of Iron Load

International Nuclear Information System (INIS)

Rehmani, Fouzia S.

2005-01-01

Iron overload is a condition in which excessive iron deposited in the liver, kidney and spleen of human beings in the patients of beta thalassemia and sickle cell anemia. Instead of its importance iron could be toxic when in excess, it damages the tissues. For the treatment of iron overload, a drug desferrioxamine mesylate has been used. It is linear trihydroxamic acid, a natural siderophore produced by streptomyces which removes the extra iron from body. Salicylhydroxamate type siderphore. In present research salicylhydroxamate was used for the complexation with dipositive metal ions which are available in biological environments such as Mn (II), Co (II), Ni (II) and Cu (II). The aim of our work was to study the competition reactions between Fe (III) and other dipositive ions; to calculate the thermodynamic data of chelation of these metal ions complexes with hydroxamate by computer program and comparison with hydroxamate complexes. (author)