A Sensor Based on LiCl/NaA Zeolite Composites for Effective Humidity Sensing.

Science.gov (United States)

Zhang, Ying; Xiang, Hongyu; Sun, Liang; Xie, Qiuhong; Liu, Man; Chen, Yu; Ruan, Shengping

2018-03-01

LiCl/NaA zeolite composites were successfully prepared by doping 1 wt%, 2 wt%, 5 wt%, and 8 wt% of LiCl into NaA zeolite. The humidity sensing properties of LiCl/NaA composites were investigated among 11% 95% relative humidity (RH). The LiCl/NaA composites exhibited better humidity sensing properties than pure NaA zeolite. The sensor made by 2 wt% Li-doped NaA zeolite possesses the best linearly in the whole RH. These results demonstrate that the LiCl/NaA composites have the potential application in humidity sensing.

Thermal stability of LiPF 6 salt and Li-ion battery electrolytes containing LiPF 6

Science.gov (United States)

Yang, Hui; Zhuang, Guorong V.; Ross, Philip N.

The thermal stability of the neat lithium hexafluorophosphate (LiPF 6) salt and of 1 molal (m) solutions of LiPF 6 in prototypical Li-ion battery solvents was studied with thermogravimetric analysis (TGA) and on-line Fourier transform infrared (FTIR). Pure LiPF 6 salt is thermally stable up to 107 °C in a dry inert atmosphere, and its decomposition path is a simple dissociation producing lithium fluoride (LiF) as solid and PF 5 as gaseous products. In the presence of water (300 ppm) in the carrier gas, its decomposition onset temperature is lowered as a result of direct thermal reaction between LiPF 6 and water vapor to form phosphorous oxyfluoride (POF 3) and hydrofluoric acid (HF). No new products were observed in 1 m solutions of LiPF 6 in ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) by on-line TGA-FTIR analysis. The storage of the same solutions in sealed containers at 85 °C for 300-420 h did not produce any significant quantity of new products as well. In particular, no alkylflurophosphates were found in the solutions after storage at elevated temperature. In the absence of either an impurity like alcohol or cathode active material that may (or may not) act as a catalyst, there is no evidence of thermally induced reaction between LiPF 6 and the prototypical Li-ion battery solvents EC, PC, DMC or EMC.

Investigations into the fast ionic conductors γ-CuBr, Li2S, Na2S, Ba2NH, NaTaN2 and Li3HoCl6 by means of neutron scattering

International Nuclear Information System (INIS)

Altorfer, F.

1994-01-01

The main topic of this work was the investigation of ionic diffusion in solids by means of neutron scattering. Experiments were carried out on the antifluorites Li 2 S, Na 2 S and γ-CuBr (zinc-blende type) as well as on Barium-Nitride-Hydride Ba 2 NH, NaTaN 2 and Li 3 HoCl 6 which represent three-and two-dimensional ionic conductors, respectively. In the sulphur based antifluorites Li 2 S and Na 2 S the occupation of the interstitial empty cube site by cations occurs at elevated temperatures. The temperature-dependence of the diffusion process has been investigated by quasielastic, incoherent neutron scattering. The cations hop between their regular lattice sites and the interstitial empty cube site, whereas the sulphur ions vibrate in good approximation harmonically even at high temperatures. The jump vectors define a three-dimensional net of possible cation paths through the crystal. The analysis of quasielastic scattering experiments on a Li 2 S single crystal enabled us to determine the jump vectors and the jump rates 1/τ. The temperature dependence of the anharmonic contributions to the copper structure factor was the main point in our neutron diffraction experiments on γ-CuBr. It could be shown that the copper density function deviates strongly from the isotropic form with increasing temperature. Barium-Nitride-Hydride is one of the few documented H - -ionic conductors. The electronic part of the ds-conductivity is only 1/10000 of the ionic contribution. Since Ba 2 NH is a layer compound, where H - and N 3- layers alternate along the c-axis, the probability of jumps out of the plane is suppressed in favour of in plane jumps. This compound is therefore a model system in which two-dimensional diffusion can be studied and in fact the analysis of the quasielastic data proved that the H-diffusion is caused by jumps between regular H - lattice sites. (author) figs., tabs., refs

A first-principles study of hydrogen storage capacity based on Li-Na-decorated silicene.

Science.gov (United States)

Sheng, Zhe; Wu, Shujing; Dai, Xianying; Zhao, Tianlong; Hao, Yue

2018-05-23

Surface decoration with alkali metal adatoms has been predicted to be promising for silicene to obtain high hydrogen storage capacity. Herein, we performed a detailed study of the hydrogen storage properties of Li and Na co-decorated silicene (Li-Na-decorated silicene) based on first-principles calculations using van der Waals correction. The hydrogen adsorption behaviors, including the adsorption order, the maximum capacity, and the corresponding mechanism were analyzed in detail. Our calculations show that up to three hydrogen molecules can firmly bind to each Li atom and six for each Na atom, respectively. The hydrogen storage capacity is estimated to be as high as 6.65 wt% with a desirable average adsorption energy of 0.29 eV/H2. It is confirmed that both the charge-induced electrostatic interaction and the orbital hybridizations play a great role in hydrogen storage. Our results may enhance our fundamental understanding of the hydrogen storage mechanism, which is of great importance for the practical application of Li-Na-decorated silicene in hydrogen storage.

New hydrogen titanium phosphate sulfate electrodes for Li-ion and Na-ion batteries

Science.gov (United States)

Zhao, Ran; Mieritz, Daniel; Seo, Dong-Kyun; Chan, Candace K.

2017-03-01

NASICON-type materials with general formula AxM2(PO4)3 (A = Li or Na, M = Ti, V, and Fe) are promising candidates for Li- and Na-ion batteries due to their open three-dimensional framework structure. Here we report the electrochemical properties of hydrogen titanium phosphate sulfate, H0.4Ti2(PO4)2.4(SO4)0.6 (HTPS), a new mixed polyanion material with NASICON structure. Micron-sized HTPS aggregates with crystallite grain size of ca. 23 nm are synthesized using a sol-gel synthesis in an acidic medium. The properties of the as-synthesized HTPS, ball-milled HTPS, and samples prepared as carbon composites using an in-situ glucose decomposition reaction are investigated. A capacity of 148 mAh g-1 corresponding to insertion of 2 Li+ per formula unit is observed in the ball-milled HTPS over the potential window of 1.5-3.4 V vs. Li/Li+. Lithiation at ca. 2.8 and 2.5 V is determined to occur through filling of the M1 and M2 sites, respectively. Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) are used characterize the HTPS before and after cycling. Evaluation of the HTPS in a Na-ion cell is also performed. A discharge capacity of 93 mAh g-1 with sodiation at ca. 2.9 and 2.2 V vs. Na/Na+ is observed.

Excitation of Li and Na atoms in collisions with He and Ne

International Nuclear Information System (INIS)

Olsen, J.Oe.; Andersen, T.; Andersen, N.

1977-01-01

Total emission cross sections and polarizations have been measured for the 2 2 S - 2 2 P, 2 2 P - 3 2 D and 2 2 P - 3 2 S LiI multiplets in Li - He,Ne collisions, and the 3 2 S - 3 2 P and 3 2 P - 3 2 D NaI multiplets in Na - He,Ne collisions in the 0.6 - 60 keV energy range. The excitation of the alkali resonance multiplet is found to be the dominant inelastic process for all four collision systems. The behaviour is very similar to the previously investigated Be + - He,Ne and Mg + - He,Ne systems. The results are compared with recent calculations by Manique et al based on a quasi-one electron description using various model potentials. Good agreement is found for Li - He with a simple Hartree-Fock frozen-core potential. The agreement is fair for Li,Na - He calculations with a Baylis type potential but poor for calculations based on Bottcher model potentials. For Ne as target all three potentials by far overestimate the size of the cross section. (Auth.)

The compressibility mechanism of Li3Na3In2F12 garnet

DEFF Research Database (Denmark)

Grzechnik, Andrzej; Balic Zunic, Tonci; Makovicky, Emil

2006-01-01

The high pressure behaviour of Li3Na3In2F12 garnet (Ia¯3d, Z = 8) is studied up to 9.2 GPa at room temperature in diamond anvil cells using xray diffraction. Its equation of state to 9.2 GPa and the pressure dependences of the structural parameters to 4.07 GPa are determined from synchrotron angle......-dispersive powder and laboratory single-crystal data, respectively. No indication of any structural phase transition in this material has been found up to 9.2 GPa. The fitting of the Murnaghan equation of state yields B0 = 36.2(5) GPa, B0 = 5.38(18), and V0 = 2051.76(0.69) °A 3. The compressibility mechanism of Li3......Na3In2F12 is attributed to the substantial bending of the In-F-Li angles linking the InF6 octahedra and LiF4 tetrahedra. The most compressible polyhedral units are the NaF8 triangulated dodecahedra. These results are discussed in relation to previous high pressure photoluminescence measurements...

Electronic structure and molecular dynamics of Na2Li

Science.gov (United States)

Malcolm, Nathaniel O. J.; McDouall, Joseph J. W.

Following the first report (Mile, B., Sillman, P. D., Yacob, A. R. and Howard, J. A., 1996, J. chem. Soc. Dalton Trans , 653) of the EPR spectrum of the mixed alkali-metal trimer Na2Li a detailed study has been made of the electronic structure and structural dynamics of this species. Two isomeric forms have been found: one of the type, Na-Li-Na, of C , symmetry and another, Li-Na-Na, of C symmetry. Also, there are two linear saddle points which correspond to 'inversion' transition structures, and a saddle point of C symmetry which connects the two minima. A molecular dynamics investigation of these species shows that, at the temperature of the reported experiments (170 K), the C minimum is not 'static', but undergoes quite rapid inversion. At higher temperatures the C minimum converts to the C form, but by a mechanism very different from that suggested by minimum energy path considerations. 2 2v s s 2v 2v s

Study of the 6Li+16O light heavy-ion system around the Coulomb barrier

International Nuclear Information System (INIS)

Glasner, K.; Ricken, L.; Kuhlmann, E.

1986-01-01

Total cross sections of the light heavy-ion reactions 16 O( 6 Li,p) 21 Ne, i=0-10, have been measured for beam energies Esub(Li)=4.5-8.0 MeV in steps of 100 keV. Additional excitation functions of the inclusive reactions 16 O( 6 Li,xy), x=p, n and α, were taken for Esub(li)=4.1-12.5 MeV. The 6 Li+ 16 O reaction can be understood as a predominant compound-nucleus process as extensive Hauser-Feshbach calculations show. A comprehensive statistical analysis yields a coherence width GAMMA=130+-20 keV for Esub(x)( 22 Na)approx.=19 MeV. Statistically significant deviations from pure fluctuation phenomena are found in most excitation functions at Esub(x)( 22 Na)=17.9, 18.4, 19.2 and 20.2 MeV. Interpreting these structures with widths 400<=GAMMAsub(tot)<=800 keV as intermediate-width resonances in terms of rotational band, tentative spin assignments can be given. (orig.)

Cubic Crystal-Structured SnTe for Superior Li- and Na-Ion Battery Anodes.

Science.gov (United States)

Park, Ah-Ram; Park, Cheol-Min

2017-06-27

A cubic crystal-structured Sn-based compound, SnTe, was easily synthesized using a solid-state synthetic process to produce a better rechargeable battery, and its possible application as a Sn-based high-capacity anode material for Li-ion batteries (LIBs) and Na-ion batteries (NIBs) was investigated. The electrochemically driven phase change mechanisms of the SnTe electrodes during Li and Na insertion/extraction were thoroughly examined utilizing various ex situ analytical techniques. During Li insertion, SnTe was converted to Li 4.25 Sn and Li 2 Te; meanwhile, during Na insertion, SnTe experienced a sequential topotactic transition to Na x SnTe (x ≤ 1.5) and conversion to Na 3.75 Sn and Na 2 Te, which recombined into the original SnTe phase after full Li and Na extraction. The distinctive phase change mechanisms provided remarkable electrochemical Li- and Na-ion storage performances, such as large reversible capacities with high Coulombic efficiencies and stable cyclabilities with fast C-rate characteristics, by preparing amorphous-C-decorated nanostructured SnTe-based composites. Therefore, SnTe, with its interesting phase change mechanisms, will be a promising alternative for the oncoming generation of anode materials for LIBs and NIBs.

Synthesis, crystal structure and spectroscopy properties of Na 3AZr(PO 4) 3 ( A=Mg, Ni) and Li 2.6Na 0.4NiZr(PO 4) 3 phosphates

Science.gov (United States)

Chakir, M.; El Jazouli, A.; de Waal, D.

2006-06-01

Na 3AZr(PO 4) 3 ( A=Mg, Ni) phosphates were prepared at 750 °C by coprecipitation route. Their crystal structures have been refined at room temperature from X-ray powder diffraction data using Rietveld method. Li 2.6Na 0.4NiZr(PO 4) 3 was synthesized through ion exchange from the sodium analog. These materials belong to the Nasicon-type structure. Raman spectra of Na 3AZr(PO 4) 3 ( A=Mg, Ni) phosphates present broad peaks in favor of the statistical distribution in the sites around PO 4 tetrahedra. Diffuse reflectance spectra indicate the presence of octahedrally coordinated Ni 2+ ions.

The electronic structure and optical properties of ABP 2O 7 ( A = Na, Li) double phosphates

Science.gov (United States)

Hizhnyi, Yu. A.; Oliynyk, A.; Gomenyuk, O.; Nedilko, S. G.; Nagornyi, P.; Bojko, R.; Bojko, V.

2008-01-01

Partial densities of states and reflection spectra of NaAlP 2O 7, KAlP 2O 7 and LiInP 2O 7 double phosphate crystals are calculated by the full-potential linear-augmented-plane-wave (FLAPW) method. Experimental reflection spectra of KAlP 2O 7, CsAlP 2O 7 and NaInP 2O 7 are measured in the 4-20 eV energy range. The values of band gaps, Eg, are found from a comparison of experiment and calculations to be 6.0 eV for NaAlP 2O 7 and KAlP 2O 7, and 4.6 eV for LiInP 2O 7.

Nanoconfined NaAlH4 Conversion Electrodes for Li Batteries

DEFF Research Database (Denmark)

Huen, Priscilla; Peru, Filippo; Charalambopoulou, Georgia

2017-01-01

-Type anode in Li-ion batteries. Here, NaAlH4 nanoconfined in carbon scaffolds as an anode material for Li-ion batteries is reported for the first time. Nanoconfined NaAlH4 was prepared by melt infiltration into mesoporous carbon scaffolds. In the first cycle, the electrochemical reversibility of nanoconfined...

Synthesis, crystal structure and electrochemical properties of the manganese-doped LiNaFe[PO{sub 4}]F materials

Energy Technology Data Exchange (ETDEWEB)

Ben Yahia, Hamdi, E-mail: benyahia.hamdi@aist.go.jp; Shikano, Masahiro, E-mail: shikano.masahiro@aist.go.jp; Sakaebe, Hikari; Kobayashi, Hironori

2013-08-15

The new compounds LiNaFe{sub 1−x}Mn{sub x}[PO{sub 4}]F (x ≤ 1/4) were synthesized by a solid state reaction route. The crystal structure of LiNaFe{sub 3/4}Mn{sub 1/4}[PO{sub 4}]F was determined from single crystal X-ray diffraction data. LiNaFe{sub 3/4}Mn{sub 1/4}[PO{sub 4}]F crystallizes with the Li{sub 2}Ni[PO{sub 4}]F-type structure, space group Pnma, a = 10.9719(13), b = 6.3528(7), c = 11.4532(13) Å, V = 798.31(16) Å{sup 3}, and Z = 8. The structure consists of edge-sharing (Fe{sub 3/4}Mn{sub 1/4})O{sub 4}F{sub 2} octahedra forming (Fe{sub 3/4}Mn{sub 1/4})FO{sub 3} chains running along the b-axis. These chains are interlinked by PO{sub 4} tetrahedra forming a three-dimensional framework with the tunnels and the cavities filled by the well-ordered sodium and lithium atoms, respectively. The manganese-doped phases show poor electrochemical behavior comparing to the iron pure phase LiNaFe[PO{sub 4}]F. - Highlights: • We investigated the synthesis of LiNaFe{sub 1−x}Mn{sub x}[PO{sub 4}]F by solid state reaction. • We demonstrated that a solid solution exist only for x ≤ 1/4. • We solved the crystal structure of LiNaFe{sub 3/4}Mn{sub 1/4}[PO{sub 4}]F using single crystal data. • We studied the electrochemical performances of LiNaFe{sub 1−x}Mn{sub x}[PO{sub 4}]F. • The Mn-doped phases have poor electrochemical performances comparing to LiNaFe[PO{sub 4}]F.

Characterization of Al-Ti phases in cycled TiF3-enhanced Na2LiAlH6

International Nuclear Information System (INIS)

Nakamura, Y.; Fossdal, A.; Brinks, H.W.; Hauback, B.C.

2006-01-01

TiF 3 -enhanced Na 2 LiAlH 6 was investigated after dehydrogenation-hydrogenation cycles by synchrotron X-ray diffraction. There was no sign of Ti after ball-milling with TiF 3 , but two types of Al-Ti phases were observed in the cycled samples. In a sample after measuring five pressure-composition isotherms in the temperature range from 170 to 250 deg. C, a fcc phase with a = 3.987 A was observed. This phase is considered to be Al 3 Ti with the L1 2 structure. Samples after one or four cycles at selected temperatures between 170 and 250 deg. C showed diffraction from another fcc phase with a ∼ 4.03 A. This indicates formation of an Al 1-y Ti y solid-solution phase with y ∼ 0.15 similar to previously reported for cycled NaAlH 4 with Ti additives

Synthesis, structure and electrochemical properties of LiNaCo{sub 0.5}Fe{sub 0.5}PO{sub 4}F fluoride-phosphate

Energy Technology Data Exchange (ETDEWEB)

Fedotov, Stanislav S. [Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Skoltech Center for Electrochemical Energy Storage, Skolkovo Institute of Science and Technology, 143026 Moscow (Russian Federation); Kuzovchikov, Sergey M.; Khasanova, Nellie R.; Drozhzhin, Oleg A.; Filimonov, Dmitriy S. [Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Karakulina, Olesia M.; Hadermann, Joke [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Abakumov, Artem M. [Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Skoltech Center for Electrochemical Energy Storage, Skolkovo Institute of Science and Technology, 143026 Moscow (Russian Federation); EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Antipov, Evgeny V. [Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow (Russian Federation)

2016-10-15

LiNaCo{sub 0.5}Fe{sub 0.5}PO{sub 4}F fluoride-phosphate was synthesized via conventional solid-state and novel freeze-drying routes. The crystal structure was refined based on neutron powder diffraction (NPD) data and validated by electron diffraction (ED) and high-resolution transmission electron microscopy (HRTEM). The alkali ions are ordered in LiNaCo{sub 0.5}Fe{sub 0.5}PO{sub 4}F and the transition metals jointly occupy the same crystallographic sites. The oxidation state and oxygen coordination environment of the Fe atoms were verified by {sup 57}Fe Mössbauer spectroscopy. Electrochemical tests of the LiNaCo{sub 0.5}Fe{sub 0.5}PO{sub 4}F cathode material demonstrated a reversible activity of the Fe{sup 3+}/Fe{sup 2+} redox couple at the electrode potential near 3.4 V and minor activity of the Co{sup 3+}/Co{sup 2+} redox couple over 5 V vs Li/Li{sup +}. The material exhibited the discharge capacity of more than 82% (theo.) regarding Fe{sup 3+}/Fe{sup 2+} in the 2.4÷4.6 V vs Li/Li{sup +} potential range. - Graphical abstract: The ball-polyhedral representation of the LiNaCo{sub 0.5}Fe{sub 0.5}PO{sub 4}F crystal structure. The MO{sub 4}F{sub 2} units are depicted as blue octahedra, PO{sub 4} units as orange tetrahedra, sodium atoms are designated as yellow (Na1), lithium – red and brown (Li2, Li3 resp.), fluorine – green, oxygen – violet spheres. - Highlights: • Freeze-drying method was successfully applied to the synthesis of LiNaCo{sub 0.5}Fe{sub 0.5}PO{sub 4}F. • The crystal structure of LiNaCo{sub 0.5}Fe{sub 0.5}PO{sub 4}F was refined based on NPD and validated by ED and HRTEM. • LiNaCo{sub 0.5}Fe{sub 0.5}PO{sub 4}F demonstrated a reversible Li de/intercalation in the 2.5÷4.6 V vs Li/Li{sup +} range.

Emission analysis of Tb3+ -and Sm3+ -ion-doped (Li2 O/Na2 O/K2 O) and (Li2 O + Na2 O/Li2 O + K2 O/K2 O + Na2 O)-modified borosilicate glasses.

Science.gov (United States)

Naveen Kumar Reddy, B; Sailaja, S; Thyagarajan, K; Jho, Young Dahl; Sudhakar Reddy, B

2018-05-01

Four series of borosilicate glasses modified by alkali oxides and doped with Tb 3+ and Sm 3+ ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5B 2 O 3 + 10SiO 2 + 5MgO + R + 0.5(Tb 2 O 3 /Sm 2 O 3 ) [where R = 10(Li 2 O /Na 2 O/K 2 O) for series A and C, and R = 5(Li 2 O + Na 2 O/Li 2 O + K 2 O/K 2 O + Na 2 O) for series B and D]. The X-ray diffraction (XRD) patterns of all the prepared glasses indicate their amorphous nature. The spectroscopic properties of the prepared glasses were studied by optical absorption analysis, photoluminescence excitation (PLE) and photoluminescence (PL) analysis. A green emission corresponding to the 5 D 4 → 7 F 5 (543 nm) transition of the Tb 3+ ions was registered under excitation at 379 nm for series A and B glasses. The emission spectra of the Sm 3+ ions with the series C and D glasses showed strong reddish-orange emission at 600 nm ( 4 G 5/2 → 6 H 7/2 ) with an excitation wavelength λ exci = 404 nm ( 6 H 5/2 → 4 F 7/2 ). Furthermore, the change in the luminescence intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Tb 3+ and Sm 3+ ions was studied to optimize the potential alkali-oxide-modified borosilicate glass. Copyright © 2017 John Wiley & Sons, Ltd.

Pre-main-sequence depletion of Li-6 and Li-7

International Nuclear Information System (INIS)

Proffitt, C.R.; Michaud, G.

1989-01-01

Depletion of Li-6 and Li-7 during premain-sequence contraction has been calculated for several evolutionary sequences. Slightly greater Li-7 depletion was found than by other recent workers. On the premain sequence, Li-6 is depleted by a factor of at least 10 in the present models for stars with T(eff) lower than 6800 K on the main sequence. Because of the shorter destruction time scale for Li-6 as compared to Li-7, the determination of the abundances of these two isotopes would place strict constraints on the structure of premain-sequence stars. 39 refs

Tuning the Solid Electrolyte Interphase for Selective Li- and Na-Ion Storage in Hard Carbon

Energy Technology Data Exchange (ETDEWEB)

Soto, Fernando A. [Department of Chemical Engineering, Texas A& M University, College Station TX 77843-3122 USA; Yan, Pengfei [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Engelhard, Mark H. [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Marzouk, Asma [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825 Doha Qatar; Wang, Chongmin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Xu, Guiliang [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Chen, Zonghai [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Amine, Khalil [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Liu, Jun [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Sprenkle, Vincent L. [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; El-Mellouhi, Fedwa [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825 Doha Qatar; Balbuena, Perla B. [Department of Chemical Engineering, Texas A& M University, College Station TX 77843-3122 USA; Li, Xiaolin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA

2017-03-07

Solid-electrolyte interphase (SEI) films with controllable properties are highly desirable for improving battery performance. In this paper, a combined experimental and theoretical approach is used to study SEI films formed on hard carbon in Li- and Na-ion batteries. It is shown that a stable SEI layer can be designed by precycling an electrode in a desired Li- or Na-based electrolyte, and that ionic transport can be kinetically controlled. Selective Li- and Na-based SEI membranes are produced using Li- or Na-based electrolytes, respectively. The Na-based SEI allows easy transport of Li ions, while the Li-based SEI shuts off Na-ion transport. Na-ion storage can be manipulated by tuning the SEI layer with film-forming electrolyte additives, or by preforming an SEI layer on the electrode surface. The Na specific capacity can be controlled to < 25 mAh g(-1); approximate to 1/10 of the normal capacity (250 mAh g(-1)). Unusual selective/ preferential transport of Li ions is demonstrated by preforming an SEI layer on the electrode surface and corroborated with a mixed electrolyte. This work may provide new guidance for preparing good ion-selective conductors using electrochemical approaches.

Tuning the Solid Electrolyte Interphase for Selective Li- and Na-Ion Storage in Hard Carbon

Energy Technology Data Exchange (ETDEWEB)

Soto, Fernando A. [Department of Chemical Engineering, Texas A& M University, College Station TX 77843-3122 USA; Yan, Pengfei [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Engelhard, Mark H. [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Marzouk, Asma [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825 Doha Qatar; Wang, Chongmin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Xu, Guiliang [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Chen, Zonghai [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Amine, Khalil [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Liu, Jun [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Sprenkle, Vincent L. [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; El-Mellouhi, Fedwa [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825 Doha Qatar; Balbuena, Perla B. [Department of Chemical Engineering, Texas A& M University, College Station TX 77843-3122 USA; Li, Xiaolin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA

2017-03-07

Solid-electrolyte interphase (SEI) with controllable properties are highly desirable to improve battery performance. In this paper, we use a combined experimental and simulation approach to study the SEI formation on hard carbon in Li and Na-ion batteries. We show that with proper additives, stable SEI can be formed on hard carbon by pre-cycling the electrode materials in Li or Na-ion electrolyte. Detailed mechanistic studies suggest that the ion transport in the SEI layer is kinetically controlled and can be tuned by the applied voltage. Selective Na and Li-ion SEI membranes are produced using the Na or Li-ion based electrolytes respectively. The large Na ion SEI allows easy transport of Li ions, while the small Li ion SEI shuts off the Na-ion transport. Na-ion storage can be manipulated by tuning the SEI with film-forming electrolyte additives or preforming a SEI on the electrodes’ surface. The Na specific capacity can be controlled to <25 mAh/g, ~1/10 of the normal capacity (250 mAh/g). Unusual selective/preferential transport of Li-ion is demonstrated by preforming a SEI on the electrode’s surface and corroborated with a mixed electrolyte. This work may provide new guidance for preparing good ion selective conductors using electrochemical approaches in the future.

Piezoelectric properties enhanced of Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} ceramic by (LiCe) modification with charge neutrality

Energy Technology Data Exchange (ETDEWEB)

Fang, Pinyang, E-mail: fpy_2000@163.com [Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Xi, Zengzhe; Long, Wei; Li, Xiaojuan [Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Li, Jin [Northwest Institute For Non-ferrous Metal Research, Xi’an 710016 (China)

2013-09-01

Graphical abstract: The oxygen vacancies were confirmed by the left figure. The role of oxygen vacancy on piezoelectric activities was obtained by comparing to the varieties of oxygen vacancy concentration and piezoelectric coefficient with (LiCe) modification. -- Highlights: • The Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} ceramic by (LiCe) modification with the charge neutrality was synthesized by the solid state reaction method. • The Curie temperature and piezoelectric coefficient were found to be T{sub c} ∼590 °C and d{sub 33} ∼32 pC/N, respectively. • The mechanism of piezoelectric activities improved by (LiCe) modification was discussed. -- Abstract: Aurivillius-type ceramics, Sr{sub 0.6−x}(LiCe){sub x/2.5}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9}(SLCBNBNO) with the charge neutrality, were synthesized by using conventional solid-state processing. Phase analysis was performed by X-ray diffraction analyses (XRD) and Raman spectroscopy. Microstructural morphology was assessed by the scanning electron microscopy (SEM). Structural, dielectric, piezoelectric, ferroelectric, and electromechanical properties of the SLCBNBNO ceramics were investigated. Piezoelectric properties were significantly enhanced compared to Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} (SBNBN) ceramic and the maximum of piezoelectric coefficient d{sub 33} of the SBNBN-LC6 ceramic was 32 pC/N with higher Curie temperature (T{sub c} ∼590 °C). In addition, mechanisms for the piezoelectric properties enhanced of the SBNBN-based ceramics were discussed.

Selective sodium intercalation into sodium nickel-manganese sulfate for dual Na-Li-ion batteries.

Science.gov (United States)

Marinova, Delyana M; Kukeva, Rosica R; Zhecheva, Ekaterina N; Stoyanova, Radostina K

2018-04-26

Double sodium transition metal sulfates combine in themselves unique intercalation properties with eco-compatible compositions - a specific feature that makes them attractive electrode materials for lithium and sodium ion batteries. Herein, we examine the intercalation properties of novel double sodium nickel-manganese sulfate, Na2Ni1/2Mn1/2(SO4)2, having a large monoclinic unit cell, through electrochemical and ex situ diffraction and spectroscopic methods. The sulfate salt Na2Ni1/2Mn1/2(SO4)2 is prepared by thermal dehydration of the corresponding hydrate salt Na2Ni1/2Mn1/2(SO4)2·4H2O having a blödite structure. The intercalation reactions on Na2Ni1-xMnx(SO4)2 are studied in two model cells: half-ion cell versus Li metal anode and full-ion cell versus Li4Ti5O12 anode by using lithium (LiPF6 dissolved in EC/DMC) and sodium electrolytes (NaPF6 dissolved in EC:DEC). Based on ex situ XRD and TEM analysis, it is found that sodium intercalation into Na2Ni1/2Mn1/2(SO4)2 takes place via phase separation into the Ni-rich monoclinic phase and Mn-rich alluaudite phase. The redox reactions involving participation of manganese and titanium ions are monitored by ex situ EPR spectroscopy. It has been demonstrated that manganese ions from the sulfate salt are participating in the electrochemical reaction, while the nickel ions remain intact. As a result, a reversible capacity of about 65 mA h g-1 is reached. The selective intercalation properties determine sodium nickel-manganese sulfate as a new electrode material for hybrid lithium-sodium ion batteries that is thought to combine the advantages of individual lithium and sodium batteries.

The optical potential for 6Li-6Li elastic scattering at 156 MeV

International Nuclear Information System (INIS)

Micek, S.; Majka, Z.; Klewe-Nebenius, H.; Rebel, H.; Gils, H.J.

1984-10-01

Elastic scattering of 6 Li from 6 Li has been studied for the beam energy of 156 MeV. The experimental differential cross section has been analysed on the basis of the optical model using various phenomenological forms. The spin-orbit interaction proves to be less significant. A semi-microscopic double-folding cluster model which generates the real part of the optical potential by an antisymmetrized d-α cluster wave function of 6 Li and α-α, d-d and d-α interactions is well able to describe the experimental data. (orig.) [de

Mechanisms of emission of particles charged in 6Li + 6Li and 6Li + 10B reactions at low energies

International Nuclear Information System (INIS)

Quebert, Jean

1964-01-01

The lithium 6 nucleus is a projectile of interest to study nuclear reactions at low energy due to the possibility to obtain high heats of reaction, and to its structure which can play an important role in the projectile-target interaction. This research thesis focused on the study of two low-energy reactions provoked by lithium projectiles. These reactions are studied within the framework of the theoretical model of aggregates. The first part presents the experimental conditions of both reactions, reports the development and analysis of nuclear plates, and the transformation of a given type of particle histogram into a spectrum in the mass centre system. The next parts report the study of the 6 Li + 6 Li reaction (previous results, kinematic analysis, spectrum of secondary particles, theoretical analysis of results) and of the 6 Li + 10 B reaction (previous results, experimental results, study of the continuous spectrum of alpha particle, reaction mechanisms)

Application of silicene, germanene and stanene for Na or Li ion storage: A theoretical investigation

International Nuclear Information System (INIS)

Mortazavi, Bohayra; Dianat, Arezoo; Cuniberti, Gianaurelio; Rabczuk, Timon

2016-01-01

Silicene, germanene and stanene likely to graphene are atomic thick material with interesting properties. We employed first-principles density functional theory (DFT) calculations to investigate and compare the interaction of Na or Li ions on these films. We first identified the most stable binding sites and their corresponding binding energies for a single Na or Li adatom on the considered membranes. Then we gradually increased the ions concentration until the full saturation of the surfaces is achieved. Our Bader charge analysis confirmed complete charge transfer between Li or Na ions with the studied 2D sheets. We then utilized nudged elastic band method to analyze and compare the energy barriers for Li or Na ions diffusions along the surface and through the films thicknesses. Our investigation findings can be useful for the potential application of silicene, germanene and stanene for Na or Li ion batteries.

Ax(H3O)2-xMn5(HPO3)6 (A = Li, Na, K and NH4): open-framework manganese(ii) phosphites templated by mixed cationic species.

Science.gov (United States)

Orive, Joseba; Fernández de Luis, Roberto; Fernández, Jesús Rodríguez; Lezama, Luis; Arriortua, María I

2016-07-26

Ax(H3O)2-xMn5(HPO3)6 (A = Li, x = 0.55 (1-Li); A = Na, x = 0.72 (2-Na); A = K, x = 0.30 (3-K); A = NH4, x = 0.59 (4-NH4)) phases were synthesized by employing mild hydrothermal conditions. 1-Li was studied by single crystal X-ray diffraction, while sodium, potassium and ammonium containing analogues were obtained as polycrystalline samples and characterized by powder X-ray diffraction. The four compounds were characterized by ICP-Q-MS, thermal analysis and XPS, IR, UV/Vis and EPR spectroscopy. Single crystal data indicate that 1-Li crystallizes in the P3[combining macron]c1 space group with lattice parameters a = 10.3764(1) Å and c = 9.4017(1) Å with Z = 2. The crystal structure of these phases is constituted by a three-dimensional [Mn(ii)5(HPO3)6](2-) anionic skeleton templated by alkali metal and ammonium cations together with protonated water molecules. Such an inorganic framework is formed by layers of edge-sharing MnO6 octahedra placed in the ab plane and joined along the c direction through phosphite pseudotetrahedra. The sheets display 12-membered ring channels parallel to the c-axis, ca. 5 Å in diameter, where the extraframework species display a strong disorder. EPR measurements point to the existence of short range ferromagnetic interactions around 12 K. Magnetic susceptibility and heat capacity measurements show that all the compounds exhibit long range antiferromagnetic order below circa 4 K, with a significant magnetocaloric effect around the Neel temperature.

Study of the structural and thermal stability of Li0.3Co2/3Ni1/6Mn1/6O2

International Nuclear Information System (INIS)

Mahmoud, Abdelfattah; Saadoune, Ismael; Difi, Siham; Sougrati, Moulay Tahar; Lippens, Pierre-Emmanuel; Amarilla, José Manuel

2014-01-01

Thermal and structural stabilities of the delithiated positive electrode material Li x Co 2/3 Ni 1/6 Mn 1/6 O 2 were studied by X-ray diffraction, magnetic and thermogravimetric analysis. In the opposite to the classical electrode materials LiNiO 2 and LiCoO 2 , the structural symmetry (S.G. R-3 m) of the starting material LiCo 2/3 Ni 1/6 Mn 1/6 O 2 is preserved during the electrochemical cycling with a small variation of the unit cell parameters. Squid measurements evidenced that practically no Ni 2+ ions were present in the lithium slab even after the lithium extraction process. For the thermal stability, the highly oxidized phase Li 0.3 Co 2/3 Ni 1/6 Mn 1/6 O 2 was tested. This delithiated phase undergoes only 5.16% weight loss after heating up to 600 °C. This weight loss has no effect on the structure symmetry as the starting α-NaFeO 2 type structure was preserved during the thermal treatment. The obtained results coupled to the excellent electrochemical features of LiCo 2/3 Ni 1/6 Mn 1/6 O 2 clearly showits ability to compete with the commercialized cathode materials

Complex phosphates in the Li(Na)3PO4-InPO4 systems

International Nuclear Information System (INIS)

Potapova, A.M.; Zimina, G.V.; Smirnova, I.N.; Novoselov, A.V.; Spiridonov, F.M.; Stefanovich, S.Yu.

2008-01-01

Subsolidus sections in the systems Li 3 PO 4 -InPO 4 (950 deg C) and Na 3 PO 4 -InPO 4 (800, 900, and 1000 deg C) have been studied by X-ray powder diffraction. The compound Li 3 In(PO 4 ) 2 has been synthesized, and the NASICON-type solid solution Li 3(1-x) In 2+x (PO 4 ) 3 (0.67 ≤ x ≤ 0.80) has been found to exist. In the system Na 3 PO 4 -InPO 4 , the solid solution Na 3(1-x) In x/3 PO 4 (0 ≤ x ≤ 0.2) and two complex phosphates exist: Na 3 In(PO 4 ) 2 and Na 3 In 2 (PO 4 ) 3 . These complex phosphates are dimorphic, with the irreversible-transition temperature equal to 675 and 820 deg C, respectively. Na 3 In(PO 4 ) 2 degrades at 920 deg C. Ionic conductivity has been measured in some phases in the system [ru

[6-chloro-3-pyridylmethyl-3H]neonicotinoids as high-affinity radioligands for the nicotinic acetylcholine receptor: preparation using NaB3H4 and LiB3H4

International Nuclear Information System (INIS)

Latli, Bachir; Casida, J.E.

1996-01-01

NaB 3 H 4 and LiB 3 H 4 at 78% and 97% isotopic enrichments, respectively, were used in the synthesis of 3 H-labeled 1-(6-chloro-3-pyridyl)-methyl-2-nitromethyleneimidazolidine (CH-IMI) and N'-[(6-chloro-3-pyridyl)methyl]-n''-cyano-n'-methylacetamidine (acetamiprid) (two very potent insecticides) and of 1-(6-chloro-3-pyridyl)methyl-2-iminoimidazolidine (desnitro-IMI) (a metabolite of the commercial insecticides imidacloprid). 6-Chloronicotinoyl chloride was treated with either NaB 3 H 4 in methanol or LiB 3 H 4 in tetrahydrofuran and the resulting alcohol transformed to 2-chloro-5-chloromethylpyridine, which was then coupled to N-cyano-N'-methylacetamidine to give [ 3 H] acetamiprid (45 Ci/mmol). 2-Chloro-5-chloro[ 3 H]methylpyridine was also reacted with ethylenediamine and the product was either refluxed in absolute ethanol with 1,1-bis(methylthio)-2-nitro-ethylene to provide [ 3 H]CH-IMI or reacted in toluene with a solution of cyanogen bromide to produce [ 3 H] desnitro-IMI (each 55 Ci/mmol. (author)

Nuclear reaction rates and primordial 6Li

International Nuclear Information System (INIS)

Nollett, K.M.; Schramm, D.N.; Lemoine, M.; Schramm, D.N.; Lemoine, M.; Schramm, D.N.

1997-01-01

We examine the possibility that big-bang nucleosynthesis (BBN) may produce nontrivial amounts of 6 Li. If a primordial component of this isotope could be observed, it would provide a new fundamental test of big-bang cosmology, as well as new constraints on the baryon density of the universe. At present, however, theoretical predictions of the primordial 6 Li abundance are extremely uncertain due to difficulties in both theoretical estimates and experimental determinations of the 2 H(α,γ) 6 Li radiative capture reaction cross section. We also argue that present observational capabilities do not yet allow the detection of primeval 6 Li in very metal-poor stars of the galactic halo. However, if the critical cross section is very high in its plausible range and the baryon density is relatively low, then improvements in 6 Li detection capabilities may allow the establishment of 6 Li as another product of BBN. It is also noted that a primordial 6 Li detection could help resolve current concerns about the extragalactic D/H determination. copyright 1997 The American Physical Society

Flame photometric determination of Na, K and Li in uranium compounds

International Nuclear Information System (INIS)

Sabato, S.F.; Lordello, A.R.

1985-01-01

A flame photometric method for the determination of Na, K and Li in uranium compounds is described. The uranium is separated by solvent extraction from hydrochloric acid medium with tri-butyl phosphate. Amounts of uranium in order of 20 μg/ml don't cause any interference in the photometric results. The element Na presents a residual concentration due to the contamination of the reagents. The relative standard deviation is about 10% for the three elements. The relative error varies with the concentration of the element and it is between 1 and 24% for Na, between O and 12% for K and between O and 33% for Li. (Author) [pt

Vrijeme latencije kao indikator iskrivljavanja odgovora na upitnicima ličnosti

OpenAIRE

Parmač, Maja; Galić, Zvonimir; Jerneić, Željko

2009-01-01

Cilj istraživanja bio je provjeriti model disimulacije na česticama upitnika ličnosti koji su postavili Holden, Kroner, Fakken i Popham (1992). Model objašnjava procese koji se nalaze u osnovi razlika u vremenima odgovaranja iskrenih ispitanika i ispitanika koji iskrivljavaju svoje odgovore. Temeljna je pretpostavka modela da ispitanici prilikom odgovaranja na upitnik ličnosti uspoređuju čestice upitnika s trenutnom kognitivnom shemom te da postoji interakcija te sheme i socijalne poželjnosti...

Theoretical Study on Cyclopeptides as the Nanocarriers for Li+, Na+, K+ and F−, Cl−, Br−

Directory of Open Access Journals (Sweden)

Lili Liu

2015-01-01

Full Text Available The interaction process between a series of cyclopeptide compounds cyclo(Glyn  (n=4,6,8 and monovalent ions (Li+, Na+, K+, F−, Cl−, and Br− was studied using theoretical calculation. The mechanism of combination between the cyclo(Glyn and ions was discussed through binding energy, Mulliken electron population, and hydrogen bond. It was found that for the same cyclopeptide the binding energy has the order of cyclo(Glyn–Li+ > cyclo(Glyn–Na+ > cyclo(Glyn–K+ and cyclo(Glyn–F− > cyclo(Glyn–Br− > cyclo(Glyn–Cl−. The binding energy manifests the stable complex of cyclo(Glyn and ions can be formed, and the different energy shows the potential use of cyclo(Glyn as nanocarriers for metal ions or the extractant for ions separation.

Borophane as a Benchmate of Graphene: A Potential 2D Material for Anode of Li and Na-Ion Batteries.

Science.gov (United States)

Jena, Naresh K; Araujo, Rafael B; Shukla, Vivekanand; Ahuja, Rajeev

2017-05-17

Borophene, single atomic-layer sheet of boron ( Science 2015 , 350 , 1513 ), is a rather new entrant into the burgeoning class of 2D materials. Borophene exhibits anisotropic metallic properties whereas its hydrogenated counterpart borophane is reported to be a gapless Dirac material lying on the same bench with the celebrated graphene. Interestingly, this transition of borophane also rendered stability to it considering the fact that borophene was synthesized under ultrahigh vacuum conditions on a metallic (Ag) substrate. On the basis of first-principles density functional theory computations, we have investigated the possibilities of borophane as a potential Li/Na-ion battery anode material. We obtained a binding energy of -2.58 (-1.08 eV) eV for Li (Na)-adatom on borophane and Bader charge analysis revealed that Li(Na) atom exists in Li + (Na + ) state. Further, on binding with Li/Na, borophane exhibited metallic properties as evidenced by the electronic band structure. We found that diffusion pathways for Li/Na on the borophane surface are anisotropic with x direction being the favorable one with a barrier of 0.27 and 0.09 eV, respectively. While assessing the Li-ion anode performance, we estimated that the maximum Li content is Li 0.445 B 2 H 2 , which gives rises to a material with a maximum theoretical specific capacity of 504 mAh/g together with an average voltage of 0.43 V versus Li/Li + . Likewise, for Na-ion the maximum theoretical capacity and average voltage were estimated to be 504 mAh/g and 0.03 V versus Na/Na + , respectively. These findings unambiguously suggest that borophane can be a potential addition to the map of Li and Na-ion anode materials and can rival some of the recently reported 2D materials including graphene.

Fragmentation properties of 6Li

International Nuclear Information System (INIS)

Lovas, R.G.; Kruppa, A.T.; Beck, R.; Dickmann, F.

1987-01-01

The α+d and t+τ cluster structure of 6 Li is described in a microscopic α+d cluster model through quantities that enter into the description of cluster fragmentation processes. The states of the separate clusters α, d, t and τ are described as superpositions of Os Slater determinants belonging to different potential size parameters. To describe both the 6 Li and fragment state realistically, nucleon-nucleon forces optimized for the used model state spaces were constructed. The fragmentation properties predicted by them slightly differ from those calculated with some forces of common use provided the latter are modified so as to reproduce the α, d and 6 Li energies. (author) 61 refs.; 9 figs

Characterization of Al-Ti phases in cycled TiF{sub 3}-enhanced Na{sub 2}LiAlH{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Y. [Department of Physics, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway)]. E-mail: yumikon@ife.no; Fossdal, A. [Department of Physics, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway); Brinks, H.W. [Department of Physics, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway); Hauback, B.C. [Department of Physics, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway)

2006-06-08

TiF{sub 3}-enhanced Na{sub 2}LiAlH{sub 6} was investigated after dehydrogenation-hydrogenation cycles by synchrotron X-ray diffraction. There was no sign of Ti after ball-milling with TiF{sub 3}, but two types of Al-Ti phases were observed in the cycled samples. In a sample after measuring five pressure-composition isotherms in the temperature range from 170 to 250 deg. C, a fcc phase with a = 3.987 A was observed. This phase is considered to be Al{sub 3}Ti with the L1{sub 2} structure. Samples after one or four cycles at selected temperatures between 170 and 250 deg. C showed diffraction from another fcc phase with a {approx} 4.03 A. This indicates formation of an Al{sub 1-y}Ti {sub y} solid-solution phase with y {approx} 0.15 similar to previously reported for cycled NaAlH{sub 4} with Ti additives.

Transfer of 6Li break-up fragments at 6Li projectile energies far above the coulomb barrier

International Nuclear Information System (INIS)

Neumann, B.; Buschmann, J.; Rebel, H.; Gils, H.J.; Klewe-Nebenius, H.

1979-05-01

Transfer of beam-velocity fragments has been experimentally investigated in 6 Li induced reactions on 208 Pb and 209 Bi in the energy range Esub(Li) = 60-156 MeV. The experimental techniques involve the observation of the target residues and measurements of the recoil ranges of heavy residual nuclei produced by charged particle bombardment. The determination of the recoil energy enables the discrimination of different reaction paths leading to the same residual nuclei. ( 6 Li, xn+p) excitation functions prove to be very similar to (α,(x-1)n) reactions at Esub(α) approximately 2/3 x Esub(Li). The results present experimental evidence for a particular reaction type indicated in previous experiments: Dissociation of the 6 Li projectile with capture of the beam-velocity alpha particle indicating an (α,xn) reaction ('internal break-up'). (orig.) [de

Luminescent properties of UV excitable blue emitting phosphors MSr4(BO3)3:Ce3+ (M = Li and Na)

International Nuclear Information System (INIS)

Guo Chongfeng; Ding Xu; Seo, Hyo Jin; Ren Zhaoyu; Bai Jintao

2011-01-01

Research highlights: → Novel blue emitting phosphors borate MSr 4 (BO 3 ) 3 (M = Li or Na) were prepared first. → Luminescent properties of phosphors borate MSr 4 (BO 3 ) 3 (M = Li or Na) were investigated extensively as candidates of blue emitting phosphor used for UV excited LED. → The optimal concentrations of dopant Ce 3+ ions in compound MSr 4 (BO 3 ) 3 (M = Li or Na) were determined as 0.05 for Li and x = 0.09 for Na excited by UV light respectively. - Abstract: A series of Ce 3+ doped novel borate phosphors MSr 4 (BO 3 ) 3 (M = Li or Na) were successfully synthesized by traditional solid-state reaction. The crystal structures and the phase purities of samples were characterized by powder X-ray diffraction. The optimal concentrations of dopant Ce 3+ ions in compound MSr 4 (BO 3 ) 3 (M = Li or Na) were determined through the measurements of photoluminescence spectra of phosphors. Ce 3+ doped phosphors MSr 4 (BO 3 ) 3 (M = Li or Na) show strong broad band absorption in UV spectral region and bright blue emission under the excitation of 345 nm light. In addition, the temperature dependences of emission spectra of M 1+x Sr 4-2x Ce x (BO 3 ) 3 (M = Li or Na) phosphors with optimal composition x = 0.05 for Li and x = 0.09 for Na excited under 355 nm pulse laser were also investigated. The experimental results indicate that the M 1+x Sr 4-2x Ce x (BO 3 ) 3 (M = Li or Na) phosphors are promising blue emitting phosphors pumped by UV light.

Resonance strength of the 1175 keV resonance in 6Li(α, γ)10B

International Nuclear Information System (INIS)

Spear, R.H.; Switkowski, Z.E.; Kennedy, D.L.; Heggie, J.C.P.

1979-01-01

The resonance strength of the 1175-keV resonance in 6 Li(α, γ) 10 B has been remeasured using a Ge(Li) detector. The result obtained is 0.40+-0.06 eV. This is in good agreement with previous measurements using NaI(T1) detectors, provided that the earlier results are multiplied by the factor 6/10 to convert them to the centre-of-mass system. Some of the consequences which arise from the failure of previous workers to make this correction before evaluating the significance of their results are discussed

Synchrotron-Radiation X-Ray Investigation of Li+/Na+ Intercalation into Prussian Blue Analogues

Directory of Open Access Journals (Sweden)

Yutaka Moritomo

2013-01-01

Full Text Available Prussian blue analogies (PBAs are promising cathode materials for lithium ion (LIB and sodium ion (SIB secondary batteries, reflecting their covalent and nanoporous host structure. With use of synchrotron-radiation (SR X-ray source, we investigated the structural and electronic responses of the host framework of PBAs against Li+ and Na+ intercalation by means of the X-ray powder diffraction (XRD and X-ray absorption spectroscopy (XAS. The structural investigation reveals a robust nature of the host framework against Li+ and Na+ intercalation, which is advantageous for the stability and lifetime of the batteries. The spectroscopic investigation identifies the redox processes in respective plateaus in the discharge curves. We further compare these characteristics with those of the conventional cathode materials, such as, LiCoO2, LiFePO4, and LiMn2O4.

The Interstellar 7Li/6Li Ratio in the Diffuse Gas Near IC 443

Science.gov (United States)

Ritchey, A. M.; Taylor, C. J.; Federman, S. R.; Lambert, D. L.

2010-11-01

Supernova remnants are believed to be the primary acceleration sites of Galactic cosmic rays (GCR), which are essential to gas-phase interstellar chemistry since they are a major source of ionization in both diffuse and dense environments. The interaction of accelerated particles with interstellar gas will also synthesize isotopes of the light elements Li, Be, and B through the spallation of CNO nuclei (producing all stable LiBeB isotopes) and through α+α fusion (yielding 6Li and 7Li, only). Type II supernovae may provide an additional source of 7Li and 11B during core collapse through neutrino-induced spallation in the He and C shells of the progenitor star (the ν-process). However, direct observational evidence for light element synthesis resulting from cosmic-ray or neutrino-induced spallation is rare. Here, we examine 7Li/6Li isotope ratios along four lines of sight through the supernova remnant IC 443 using observations of the Li I λ6707 doublet made with the Hobby-Eberly Telescope (HET) at McDonald Observatory. The 7Li/6Li ratio in the general interstellar medium is expected to be similar to the ratio of ~12 that characterizes solar system material. A local enhancement in the cosmic-ray flux will act to lower 7Li/6Li, yielding a ratio of ~2 when cosmic rays dominate Li synthesis. Gamma-ray emission from IC 443 provides strong evidence for the interaction of cosmic rays accelerated by the remnant with the ambient atomic and molecular gas. Yet this material has also been contaminated by the ejecta of a Type II supernova, which should be enriched in 7Li. We are seeking 7Li/6Li ratios that are either higher than the solar system ratio as a result of the ν-process or lower due to cosmic-ray spallation. Since the fine structure separation of the Li I doublet is comparable to the isotope shift (~7 km s-1) and each fine structure line is further split into hyperfine components, the velocity structure along the line of sight must be carefully constrained if

THE NEW DETECTIONS OF 7Li/6Li ISOTOPIC RATIO IN THE INTERSTELLAR MEDIA

International Nuclear Information System (INIS)

Kawanomoto, S.; Kajino, T.; Aoki, W.; Ando, H.; Noguchi, K.; Tanaka, W.; Bessell, M.; Suzuki, T. K.; Honda, S.; Izumiura, H.; Kambe, E.; Okita, K.; Watanabe, E.; Yoshida, M.; Sadakane, K.; Sato, B.; Tajitsu, A.; Takada-Hidai, M.

2009-01-01

We have determined the isotopic abundance ratio of 7 Li/ 6 Li in the interstellar media (ISMs) along lines of sight to HD169454 and HD250290 using the High-Dispersion Spectrograph on the Subaru Telescope. We also observed ζ Oph for comparison with previous data. The observed abundance ratios were 7 Li/ 6 Li = 8.1 +3.6 -1.8 and 6.3 +3.0 -1.7 for HD169454 and HD250290, respectively. These values are in reasonable agreement with those observed previously in the solar neighborhood ISMs within ±2σ error bars and are also consistent with our measurement of 7 Li/ 6 Li = 7.1 +2.9 -1.6 for a cloud along the line of sight to ζ Oph. This is good evidence for homogeneous mixing and instantaneous recycling of the gas component in the Galactic disk. We also discuss several source compositions of 7 Li, Galactic cosmic-ray interactions, stellar nucleosynthesis, and big bang nucleosynthesis.

The reaction d(α,γ)6Li at low energies and the primordial nucleosynthesis of 6Li

International Nuclear Information System (INIS)

Cecil, F.E.; Yan, J.; Galovich, C.S.

1996-01-01

We have searched for the reaction d(α,γ) 6 Li at an α-d center-of-mass energy of 53 keV. An upper limit on the reaction S factor is 2.0x10 -7 MeVb at the 90% confidence level, corresponding to a limit on the synthesis of 6 Li from a standard big bang of 0.9% of the present abundance for a total baryon-to-photon ratio 2.86 10 6 Li-to- 7 Li isotopic abundance ratio immediately after a standard big bang is constrained to be less than 0.85%, considerably less than a recent measurement of this ratio in a metal-poor, Population II halo star. copyright 1996 The American Physical Society

Effect of divalent impurities on some physical properties of LiF and NaF; Influence des impuretes divalentes sur quelques proprietes physiques du LiF et du NaF

Energy Technology Data Exchange (ETDEWEB)

Laj, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-05-01

The ionic thermo-currents technique is applied to the study of impurity vacancy dipoles in LiF and NaF doped with several divalent cations. In LiF only one ITC band is observed whatever the impurity studied. In NaF on the contrary two ITC bands are present, one corresponding to the one observed in LiF, the other one, intense in the case of small impurities, at lower temperature. A parallel EPR study in the case of Mn{sup 2+} doped samples shows that the band observed in LiF and the corresponding one in NaF are due to the relaxation of dipoles formed by the association of an impurity and a vacancy in the next nearest position. The knowledge of the properties of the dipoles allows to show that the room temperature ionic conductivity of LiF is conditioned by the equilibrium: M{sup ++} {open_square}+ {yields} M{sup ++} + {open_square}+. It is also shown that the isolated cation vacancy originating from this dissociation is responsible for the enhancement of {gamma}-ray coloration of LiF doped with divalent cation impurities. A paramagnetic center ascribed to the presence of Mn{sup 0} isolated in the lattice is also studied. The value of the hyperfine interaction and its temperature dependence are in good agreement with both the theory and the other experimental results. Finally it is shown that the disappearance of dipoles by annealing is related to the formation of complexes involving OH{sup -} ions, probably of the M(OH){sub 2} type, with the two OH{sup -} ions occupying a single fluorine site. (author) [French] La technique des thermocourants ioniques est appliquee a l'etude des dipoles lacune-impurete dans LiF et NaF dopes avec plusieurs cations divalents. Dans LiF on met en evidence un seul pic de thermocourant quelle que soit l'impurete consideree. Dans NaF au contraire deux pics de thermocourants sont presents, l'un correspondant a celui observe dans LiF, l'autre, dominant dans le cas des impuretes de petite taille, a plus basse temperature. Une etude parallelle

Effect of divalent impurities on some physical properties of LiF and NaF; Influence des impuretes divalentes sur quelques proprietes physiques du LiF et du NaF

Energy Technology Data Exchange (ETDEWEB)

Laj, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-05-01

The ionic thermo-currents technique is applied to the study of impurity vacancy dipoles in LiF and NaF doped with several divalent cations. In LiF only one ITC band is observed whatever the impurity studied. In NaF on the contrary two ITC bands are present, one corresponding to the one observed in LiF, the other one, intense in the case of small impurities, at lower temperature. A parallel EPR study in the case of Mn{sup 2+} doped samples shows that the band observed in LiF and the corresponding one in NaF are due to the relaxation of dipoles formed by the association of an impurity and a vacancy in the next nearest position. The knowledge of the properties of the dipoles allows to show that the room temperature ionic conductivity of LiF is conditioned by the equilibrium: M{sup ++} {open_square}+ {yields} M{sup ++} + {open_square}+. It is also shown that the isolated cation vacancy originating from this dissociation is responsible for the enhancement of {gamma}-ray coloration of LiF doped with divalent cation impurities. A paramagnetic center ascribed to the presence of Mn{sup 0} isolated in the lattice is also studied. The value of the hyperfine interaction and its temperature dependence are in good agreement with both the theory and the other experimental results. Finally it is shown that the disappearance of dipoles by annealing is related to the formation of complexes involving OH{sup -} ions, probably of the M(OH){sub 2} type, with the two OH{sup -} ions occupying a single fluorine site. (author) [French] La technique des thermocourants ioniques est appliquee a l'etude des dipoles lacune-impurete dans LiF et NaF dopes avec plusieurs cations divalents. Dans LiF on met en evidence un seul pic de thermocourant quelle que soit l'impurete consideree. Dans NaF au contraire deux pics de thermocourants sont presents, l'un correspondant a celui observe dans LiF, l'autre, dominant dans le cas des impuretes de petite taille, a plus basse temperature

Fabrication and characterization of 6Li-enriched Li2TiO3 pebbles for a high Li-burnup irradiation test

International Nuclear Information System (INIS)

Tsuchiya, Kunihiko; Kawamura, Hiroshi

2006-10-01

Lithium titanate (Li 2 TiO 3 ) pebbles are considered to be a candidate material of tritium breeders for fusion reactor from viewpoints of easy tritium release at low temperatures (about 300degC) and chemical stability. In the present study, trial fabrication tests of 6 Li-enriched Li 2 TiO 3 pebbles of 1mm in diameter were carried out by a wet process with a dehydration reaction, and characteristics of the 6 Li-enriched Li 2 TiO 3 pebbles were evaluated for preparation of a high Li-burnup test in a testing reactor. Powder of 96at% 6 Li-enriched Li 2 TiO 3 was prepared by a solid state reaction, and two kinds of 6 Li-enriched Li 2 TiO 3 pebbles, namely un-doped and TiO 2 -doped Li 2 TiO 3 pebbles, were fabricated by the wet process. Based on results of the pebble fabrication tests, two kinds of 6 Li-enriched Li 2 TiO 3 pebbles were successfully fabricated with target values (density: 80-85%T.D., grain size: 2 TiO 3 pebbles was a satisfying value of about 1.05. Contact strength of these pebbles was about 6300MPa, which was almost the same as that of the Li 2 TiO 3 pebbles with natural Li. (author)

Bibliographical review about Na/Li geo-thermometry and lithium isotopes applied to worldwide geothermal waters. Final report

International Nuclear Information System (INIS)

Sanjuan, B.; Millot, R.

2009-09-01

This study is performed within the framework of the FP6 European project HITI (High Temperature Instruments for supercritical geothermal reservoir characterization and exploitation). This research project, co-funded by EU and the different partners, aims to provide geophysical and geochemical sensors and methods to evaluate deep geothermal wells up to supercritical conditions (T > 370 deg. C), which are more cost-effective than those of the conventional wells. A deep geothermal well is currently being drilled for this purpose into the Krafla area, Iceland, as part of the IDDP ('Iceland Deep Drilling Project') and with joint funding from Icelandic industry and science Institutes. Another deep well will be drilled in the Reykjanes peninsula, Iceland, within the framework of the same project. This study, a bibliographical review about the Na/Li geo-thermometer and lithium isotopes applied on the world geothermal waters, is the first step of the task envisaged by BRGM to use and validate the sodium-lithium (Na-Li) chemical geo-thermometer on Icelandic geothermal waters at temperatures ranging from 25 to 500 deg. C. In this study, more than 120 temperature and chemical data from world geothermal and oil-fields, sedimentary basins, oceanic ridges, emerged rifts and island arcs have been collected and investigated. These additional data have allowed to confirm and refine the three existing Na/Li thermometric relationships. Moreover, a new Na/Li thermometric relationship relative to the processes of seawater or dilute seawater-basalt interaction occurring in the oceanic ridges and emerged rifts is proposed. Even if the running of Na/Li is still poorly understood, the existence of a new thermometric relationship confirms that the Na/Li ratios not only depend on the temperature but also on other parameters such as the fluid salinity and origin, or the nature of the reservoir rocks in contact with the geothermal fluids. For most of the geothermal waters in contact with

Velocity of sound in, and adiabatic compressibility of, Molten LiF-NaF, LiF-KF, NaF-KF mixtures

International Nuclear Information System (INIS)

Minchenko, V.I.; Konovalov, Y.V.; Smirnov, M.V.

1986-01-01

The authors measured the velocity of sound as a function of temperature at 1.5 zHM frequency in LiF-NaF, NaF-KF, LiF-KF melts over the entire range of their compositions. The measurements were made by comparison of the phases of a reference pulse signal and a signal reflected from the bottom of the crucible. The specified temperatures were maintained constant within plus or minus 1 degree. The sound conductor consisted of a cylindrical rod of sintered beryllium oxide, which does not interact with test melts. The study shows that the velocity of sound decreases linearly with increase of the temperature. The values of the constants of the empirical equations are presented in a table, with indication of the temperature range. The dependence of the velocity of sound on composition of the melts is shown, where isotherms for 1250 K are given as an example. Variation of the composition by 1-2 mole % leads to increase or decrease of the velocity of sound by 5-10 m

The different Li/Na ion storage mechanisms of nano Sb2O3 anchored on graphene

Science.gov (United States)

Li, Hai; Qian, Kun; Qin, Xianying; Liu, Dongqing; Shi, Ruiying; Ran, Aihua; Han, Cuiping; He, Yan-Bing; Kang, Feiyu; Li, Baohua

2018-05-01

The antimony oxide/reduced graphene oxide (Sb2O3/rGO) nanocomposites are used as anode of Li-ion and Na-ion batteries (LIBs and NIBs). However, it is unclear about Li-ion and Na-ion storage mechanism in Sb2O3/rGO nanocomposites. Herein, the conversion-alloying mechanisms of Sb2O3/rGO anodes for Na-ion and Li-ion storage are comparatively studied with a combined in-situ XRD and quasi in-situ XPS method. The distinct behaviours are monitored during (de)lithiation and (de)sodiation with respect to crystal structure and chemical composition evolution. It is evidenced that the Na-ion can be easily transported to the inner part of the Sb2O3, where the Li-ion almost cannot reach, leading to a fully transformation during sodiation. In addition, the conversion reaction product of amorphous Na2O display their better chemical stability than amorphous Li2O during electrochemical cycles, which contribute to a stable and long cycling life of NIBs. This work gain insight into the high-capacity anodes with conversation-alloying mechanism for NIBs.

Crystallization behavior of (1 - x)Li2O.xNa2O.Al2O3.4SiO2 glasses

International Nuclear Information System (INIS)

Wang, Moo-Chin; Cheng, Chih-Wei; Chang, Kuo-Ming; Hsi, Chi-Shiung

2010-01-01

The crystallization behavior of the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of β-spodumene. The isothermal crystallization kinetics of β-spodumene from the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of β-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na 2 O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na 2 O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses.

Destabilized LiBH4-NaAlH4 Mixtures Doped with Titanium Based Catalysts

DEFF Research Database (Denmark)

Shi, Qing; Yu, Xuebin; Feidenhans'l, Robert

2008-01-01

We investigate the hydrogen storage properties of the mixed complex hydride LiBH4-NaAlH4 system, both undoped and doped with a TiCl3 additive. The mixed system is found to initiate a transformation to LiBH4-NaAlH4 after ball-milling, and the doped system is found to have a significant lower hydro...

Pressure-induced changes in Cr3+-doped elpasolites and LiCaAlF6: Interpretation of macroscopic data

DEFF Research Database (Denmark)

Trueba, A. ,; García Lastra, Juan Maria; Aramburu, J. A.

2010-01-01

In the research of pressure effects on Cr3+-doped insulating lattices, it is crucial to understand the dependence of the 10Dq parameter on the sample volume, V. This problem is explored in the present work through ab initio calculations on Cr3+-doped K2NaScF6, Cs2NaYCl6, and Cs2NaYBr6 elpasolite...... dependence on V−m/3 for LiCaAlF6:Cr3+ where the measured exponent m=2.3 is seemingly anomalous when compared to the values found for ruby (m=4.5) or NiO (m=5)....

Evaluation of Ce3+ and alkali metal ions Co-doped LiSrAlF6 crystalline scintillators

International Nuclear Information System (INIS)

Wakahara, Shingo; Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui; Pejchal, Jan; Kurosawa, Shunsuke; Suzuki, Shotaro; Kawaguchi, Noriaki; Fukuda, Kentaro; Yoshikawa, Akira

2013-01-01

High scintillation efficiency of Eu-doped LiSrAlF 6 (LiSAF) and LiCaAlF 6 (LiCAF) codoped with alkali metal ions has been reported in our recent studies. Thus in this paper, we demonstrated the scintillation properties of 1% Ce-doped LiSAF crystals with 1% alkali metal ions co-doping to increase the light yield and understand the scintillation mechanism. The crystals showed intense emission band corresponding to the 5d-4f transition of Ce 3+ , and their light yields under thermal neutron excitation were higher than that of the Ce only doped crystal. Especially, the light yield of Ce–Na co-doped crystal exceeded about two times that of Ce only doped one. -- Highlights: ► Ce-doped and alkali metal co-doped LiSAF crystals were grown by μ-PD method. ► Alkali metal co-doped crystals showed higher light yield than Ce only doped crystal. ► Decay time of alkali metal co-doped LiSAF were longer than that of Ce only doped one

In Situ Tracking Kinetic Pathways of Li+/Na+ Substitution during Ion-Exchange Synthesis of LixNa1.5-xVOPO4F0.5.

Science.gov (United States)

Park, Young-Uk; Bai, Jianming; Wang, Liping; Yoon, Gabin; Zhang, Wei; Kim, Hyungsub; Lee, Seongsu; Kim, Sung-Wook; Looney, J Patrick; Kang, Kisuk; Wang, Feng

2017-09-13

Ion exchange is a ubiquitous phenomenon central to wide industrial applications, ranging from traditional (bio)chemical separation to the emerging chimie douce synthesis of materials with metastable structure for batteries and other energy applications. The exchange process is complex, involving substitution and transport of different ions under non-equilibrium conditions, and thus difficult to probe, leaving a gap in mechanistic understanding of kinetic exchange pathways toward final products. Herein, we report in situ tracking kinetic pathways of Li + /Na + substitution during solvothermal ion-exchange synthesis of Li x Na 1.5-x VOPO 4 F 0.5 (0 ≤ x ≤ 1.5), a promising multi-Li polyanionic cathode for batteries. The real-time observation, corroborated by first-principles calculations, reveals a selective replacement of Na + by Li + , leading to peculiar Na + /Li + /vacancy orderings in the intermediates. Contradicting the traditional belief of facile topotactic substitution via solid solution reaction, an abrupt two-phase transformation occurs and predominantly governs the kinetics of ion exchange and transport in the 1D polyanionic framework, consequently leading to significant difference of Li stoichiometry and electrochemical properties in the exchanged products. The findings may help to pave the way for rational design of ion exchange synthesis for making new materials.

Removal of SO42− from Li2CO3 by Recrystallization in Na2CO3 Solution

Directory of Open Access Journals (Sweden)

Wei Cai

2018-01-01

Full Text Available Li2CO3 with high purity is an important raw material for the fabrication of lithium rechargeable batteries. This paper reports a facile recrystallization way to produce Li2CO3 with high purity from commercial Li2CO3 containing 0.8 wt % of SO42− by the treatment of the commercial Li2CO3 in Na2CO3 solution. The increase of temperature from 30 °C to 90 °C favored the recrystallization of Li2CO3 in Na2CO3 solution and promoted the removal of SO42− adsorbed or doped on/in the commercial Li2CO3. The content of SO42− in Li2CO3 decreased to 0.08 wt % after the treatment of the commercial Li2CO3 in 1.0 mol·L−1 Na2CO3 solution at 90 °C for 10.0 h.

Photoionization of Li and Na in Debye plasma environments

International Nuclear Information System (INIS)

Sahoo, Satyabrata; Ho, Y.K.

2006-01-01

A calculation of the photoionization cross sections is presented for alkali-metal atoms such as Li and Na in plasma environments. The computational scheme is based on the complex coordinate rotation method. A model potential formalism has been used to simplify the computational complexity of the problems of making quantitative predictions of properties and interactions of many electron systems in Debye plasmas. The plasma environment is found to appreciably influence the photoionization cross sections. In this regard the photoionization cross sections of isolated atoms are also discussed that is found to be in good agreement with the previous theoretical results. It is observed that the strong plasma screening effect remarkably alters the photoionization cross sections near the ionization threshold. The Cooper minimum in the photoionization cross sections of Na shifts toward the higher energy as the plasma screening effect increases. For Li, the Cooper minimum is uncovered in strong plasma environments. This is the first time such structures have been determined

Bibliographical review about Na/Li geo-thermometry and lithium isotopes applied to worldwide geothermal waters. Final report

Energy Technology Data Exchange (ETDEWEB)

Sanjuan, B.; Millot, R.

2009-09-15

This study is performed within the framework of the FP6 European project HITI (High Temperature Instruments for supercritical geothermal reservoir characterization and exploitation). This research project, co-funded by EU and the different partners, aims to provide geophysical and geochemical sensors and methods to evaluate deep geothermal wells up to supercritical conditions (T > 370 deg. C), which are more cost-effective than those of the conventional wells. A deep geothermal well is currently being drilled for this purpose into the Krafla area, Iceland, as part of the IDDP ('Iceland Deep Drilling Project') and with joint funding from Icelandic industry and science Institutes. Another deep well will be drilled in the Reykjanes peninsula, Iceland, within the framework of the same project. This study, a bibliographical review about the Na/Li geo-thermometer and lithium isotopes applied on the world geothermal waters, is the first step of the task envisaged by BRGM to use and validate the sodium-lithium (Na-Li) chemical geo-thermometer on Icelandic geothermal waters at temperatures ranging from 25 to 500 deg. C. In this study, more than 120 temperature and chemical data from world geothermal and oil-fields, sedimentary basins, oceanic ridges, emerged rifts and island arcs have been collected and investigated. These additional data have allowed to confirm and refine the three existing Na/Li thermometric relationships. Moreover, a new Na/Li thermometric relationship relative to the processes of seawater or dilute seawater-basalt interaction occurring in the oceanic ridges and emerged rifts is proposed. Even if the running of Na/Li is still poorly understood, the existence of a new thermometric relationship confirms that the Na/Li ratios not only depend on the temperature but also on other parameters such as the fluid salinity and origin, or the nature of the reservoir rocks in contact with the geothermal fluids. For most of the geothermal waters in contact

Comparison of electrochemical performances of olivine NaFePO4 in sodium-ion batteries and olivine LiFePO4 in lithium-ion batteries.

Science.gov (United States)

Zhu, Yujie; Xu, Yunhua; Liu, Yihang; Luo, Chao; Wang, Chunsheng

2013-01-21

Carbon-coated olivine NaFePO(4) (C-NaFePO(4)) spherical particles with a uniform diameter of ∼80 nm are obtained by chemical delithiation and subsequent electrochemical sodiation of carbon-coated olivine LiFePO(4) (C-LiFePO(4)), which is synthesized by a solvothermal method. The C-NaFePO(4) electrodes are identical (particle size, particle size distribution, surface coating, and active material loading, etc.) to C-LiFePO(4) except that Li ions in C-LiFePO(4) are replaced by Na ions, making them ideal for comparison of thermodynamics and kinetics between C-NaFePO(4) cathode in sodium-ion (Na-ion) batteries and C-LiFePO(4) in lithium-ion (Li-ion) batteries. In this paper, the equilibrium potentials, reaction resistances, and diffusion coefficient of Na in C-NaFePO(4) are systematically investigated by using the galvanostatic intermittent titration technique (GITT), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), and compared to those of the well-known LiFePO(4) cathodes in Li-ion batteries. Due to the lower diffusion coefficient of Na-ion and higher contact and charge transfer resistances in NaFePO(4) cathodes, the rate performance of C-NaFePO(4) in Na-ion batteries is much worse than that of C-LiFePO(4) in Li-ion batteries. However, the cycling stability of C-NaFePO(4) is almost comparable to C-LiFePO(4) by retaining 90% of its capacity even after 100 charge-discharge cycles at a charge-discharge rate of 0.1 C.

Endurance testing with Li/Na electrolyte

Energy Technology Data Exchange (ETDEWEB)

Ong, E.T.; Remick, R.J.; Sishtla, C.I. [Institute of Gas Technology, Des Plaines, IL (United States)

1996-12-31

The Institute of Gas Technology (IGT), under subcontract to M-C Power Corporation under DOE funding, has been operating bench-scale fuel cells to investigate the performance and endurance issues of the Li/Na electrolyte because it offers higher ionic conductivity, higher exchange current densities, lower vapor pressures, and lower cathode dissolution rates than the Li/K electrolyte. These cells have continued to show higher performance and lower decay rates than the Li/K cells since the publication of our two previous papers in 1994. In this paper, test results of two long-term 100-cm{sup 2} bench scale cells are discussed. One cell operated continuously at 160 mA/cm{sup 2} for 17,000 hours with reference gases (60H{sub 2}/20CO{sub 2}/20H{sub 2}O fuel at 75% utilization and 30CO{sub 2}/70 air oxidant humidified at room temperature at 50% utilization). The other cell operated at 160 mA/cm{sup 2} for 6900 hours at 3 atm with system gases (64H{sub 2}/16CO{sub 2}/20H{sub 2}O at 75% utilization and an M-C Power system-defined oxidant at 40% utilization). Both cells have shown the highest performance and longest endurance among IGT cells operated to date.

Microstructural Analysis of the Effects of Thermal Runaway on Li-Ion and Na-Ion Battery Electrodes

Energy Technology Data Exchange (ETDEWEB)

Finegan, Donal [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Robinson, James B. [University College London; Heenan, Thomas M. M. [University College London; Smith, Katherine [Sharp Laboratories of Europe; Kendrick, Emma [Sharp Laboratories of Europe; University College London; Brett, Daniel J. L. [University College London; Shearing, Paul R. [University College London

2017-12-06

Thermal runaway is a phenomenon that occurs due to self-sustaining reactions within batteries at elevated temperatures resulting in catastrophic failure. Here, the thermal runaway process is studied for a Li-ion and Na-ion pouch cells of similar energy density (10.5 Wh, 12 Wh, respectively) using accelerating rate calorimetry (ARC). Both cells were constructed with a z-fold configuration, with a standard shutdown separator in the Li-ion and a low-cost polypropylene (PP) separator in the Na-ion. Even with the shutdown separator, it is shown that the self-heating rate and rate of thermal runaway in Na-ion cells is significantly slower than that observed in Li-ion systems. The thermal runaway event initiates at a higher temperature in Na-ion cells. The effect of thermal runaway on the architecture of the cells is examined using X-ray microcomputed tomography, and scanning electron microscopy (SEM) is used to examine the failed electrodes of both cells. Finally, from examination of the respective electrodes, likely due to the carbonate solvent containing electrolyte, it is suggested that thermal runaway in Na-ion batteries (NIBs) occurs via a similar mechanism to that reported for Li-ion cells.

Thermal expansion and temperature variation of elastic constants of Li(H,D) and Na(H,D) systems

International Nuclear Information System (INIS)

Islam, A.K.M.A.; Hoque, M.T.

1994-11-01

An analysis of thermal expansion of Li(H,D) systems up to melting temperature has been performed using the theory of anharmonic lattice. The study has for the first time been extended to Na(H,D) systems where very little or no data are available. The calculated lattice constants of Li(H,D) systems show quite good agreement with experiment. The success of the present calculation with Li(H,D) and room temperature lattice constant data for Na(H,D) given an indication of the reliability of the computed lattice constants and thermal expansion coefficients for Na(H,D) systems. The study also allows us to predict the hitherto unknown lattice constants of Na(H,D) crystal at 0K. The temperature dependence of elastic constants for Li(H,D) systems has also been evaluated. Comparison with measurements shows the reliability of the present calculations. (author). 45 refs, 4 figs

Electron transfer in keV Li+-Na*(3p) collisions: Pt.2. Molecular basis model

International Nuclear Information System (INIS)

Machholm, M.; Courbin, C.

1996-01-01

The velocity dependence of state-to-state integral cross sections for electron transfer and excitation in Li + -Na(3s, 3p) collisions is studied in the 0.05-0.3 au velocity range using the impact parameter semi-classical method and a 28-state molecular orbital basis model including a common translation factor. The initial orbital alignment dependence of electron transfer is in fair agreement with recent experiments and with atomic orbital model calculations. The main electron transfer channel from Na*(3p) is to the Li*(2p) states. The integral cross sections from an aligned or oriented Na*(3p) state to an aligned or oriented Li*(2p) state and vice versa and the corresponding alignment and orientation parameters are presented as a function of the impact velocity. (author)

Structural and impurity phase transitions of LiNaSO4:RE probed using cathodo-thermoluminescence

Science.gov (United States)

Maghrabi, M.; Finch, A. A.; Townsend, P. D.

2008-11-01

Spectrally resolved cathodo-thermoluminescence spectra of rare earth (RE) doped LiNaSO4 measured from 20 to 673 K reveal several anomalies in the RE emission lines and intensities. The low (20-300 K) temperature data show a discontinuous change in intensity at ~170 K that is either a marked intensity enhancement or a drop truncating the entire spectrum. Such an effect on the host luminescence has previously been assigned to a transition between cubic and hexagonal polymorphs of ice nanoparticle inclusions. Similar, but less profound anomalies are seen above room temperature (300-673 K) where the changes take the form of either a discontinuity in intensity at ~480 K or reduced intensity in the range 430-530 K. There are changes in the relative intensities of different emission lines of the same dopant in this temperature range. Such high temperature variations are ascribed to structural phase changes within the LiNaSO4 crystals. The behaviours may result from Li-poor surfaces or twin boundaries behaving like Na2SO4. This phase change is suggested in the open literature for LiNaSO4 but not yet fully documented, perhaps because the effects span a wide range of temperatures or due to experimental features inherent in most luminescence facilities.

Effect of divalent impurities on some physical properties of LiF and NaF

International Nuclear Information System (INIS)

Laj, C.

1969-05-01

The ionic thermo-currents technique is applied to the study of impurity vacancy dipoles in LiF and NaF doped with several divalent cations. In LiF only one ITC band is observed whatever the impurity studied. In NaF on the contrary two ITC bands are present, one corresponding to the one observed in LiF, the other one, intense in the case of small impurities, at lower temperature. A parallel EPR study in the case of Mn 2+ doped samples shows that the band observed in LiF and the corresponding one in NaF are due to the relaxation of dipoles formed by the association of an impurity and a vacancy in the next nearest position. The knowledge of the properties of the dipoles allows to show that the room temperature ionic conductivity of LiF is conditioned by the equilibrium: M ++ □+ → M ++ + □+. It is also shown that the isolated cation vacancy originating from this dissociation is responsible for the enhancement of γ-ray coloration of LiF doped with divalent cation impurities. A paramagnetic center ascribed to the presence of Mn 0 isolated in the lattice is also studied. The value of the hyperfine interaction and its temperature dependence are in good agreement with both the theory and the other experimental results. Finally it is shown that the disappearance of dipoles by annealing is related to the formation of complexes involving OH - ions, probably of the M(OH) 2 type, with the two OH - ions occupying a single fluorine site. (author) [fr

Raman spectra from very concentrated aqueous NaOH and from wet and dry, solid, and anhydrous molten, LiOH, NaOH, and KOH.

Science.gov (United States)

Walrafen, George E; Douglas, Rudolph T W

2006-03-21

High-temperature, high-pressure Raman spectra were obtained from aqueous NaOH solutions up to 2NaOHH2O, with X(NaOH)=0.667 at 480 K. The spectra corresponding to the highest compositions, X(NaOH)> or =0.5, are dominated by H3O2-. An IR xi-function dispersion curve for aqueous NaOH, at 473 K and 1 kbar, calculated from the data of Franck and Charuel indicates that the OH- ion forms H3O2- by preferential H bonding with nonhydrogen-bonded OH groups. Raman spectra from wet to anhydrous, solid LiOH, NaOH, and KOH yield sharp, symmetric OH- stretching peaks at 3664, 3633, and 3596 cm(-1), respectively, plus water-related, i.e., H3O2-, peaks near LiOH, 3562 cm(-1), NaOH, 3596 cm(-1), and, KOH, 3500 cm(-1). Absence of H3O2- peaks from the solid assures that the corresponding melt is anhydrous. Raman spectra from the anhydrous melts yield OH- stretching peak frequencies: LiOH, 3614+/-4 cm(-1), 873 K; NaOH, 3610+/-2 cm(-1), 975 K; and, KOH, 3607+/-2 cm(-1), 773 K, but low-frequency asymmetry due to ion-pair interactions is present which is centered near 3550 cm(-1). The ion-pair-related asymmetry corresponds to the sole IR maximum near 3550 cm(-1) from anhydrous molten NaOH, at 623 K. Bose-Einstein correction of published low-frequency Raman data from molten LiOH revealed an acoustic phonon, near 205 cm(-1), related to restricted translation of OH- versus Li+, and an optical phonon, at 625 cm(-1) and tau approximately 0.05 ps, due to protonic precession and/or pendular motion. Strong H bonding between water and the O atom of OH- forms H3O2-, but the proton of OH- does not bond with H significantly. Large Raman bandwidths (aqueous solutions) are explained in terms of inhomogeneous broadening due to proton transfer in a double well. Vibrational assignments are presented for H3O2-.

[6-chloro-3-pyridylmethyl-{sup 3}H]neonicotinoids as high-affinity radioligands for the nicotinic acetylcholine receptor: preparation using NaB{sup 3}H{sub 4} and LiB{sup 3}H{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Latli, Bachir; Casida, J.E. [California Univ., Berkeley, CA (United States). Dept. of Environmental Science Policy and Management; Chit Than; Morimoto, Hiromi; Williams, P.G. [Lawrence Berkeley National Lab., CA (United States)

1996-11-01

NaB{sup 3}H{sub 4} and LiB{sup 3}H{sub 4} at 78% and 97% isotopic enrichments, respectively, were used in the synthesis of {sup 3}H-labeled 1-(6-chloro-3-pyridyl)-methyl-2-nitromethyleneimidazolidine (CH-IMI) and N`-[(6-chloro-3-pyridyl)methyl]-n``-cyano-n`-methylacetamidine (acetamiprid) (two very potent insecticides) and of 1-(6-chloro-3-pyridyl)methyl-2-iminoimidazolidine (desnitro-IMI) (a metabolite of the commercial insecticides imidacloprid). 6-Chloronicotinoyl chloride was treated with either NaB{sup 3}H{sub 4} in methanol or LiB{sup 3}H{sub 4} in tetrahydrofuran and the resulting alcohol transformed to 2-chloro-5-chloromethylpyridine, which was then coupled to N-cyano-N`-methylacetamidine to give [{sup 3}H] acetamiprid (45 Ci/mmol). 2-Chloro-5-chloro[{sup 3}H]methylpyridine was also reacted with ethylenediamine and the product was either refluxed in absolute ethanol with 1,1-bis(methylthio)-2-nitro-ethylene to provide [{sup 3}H]CH-IMI or reacted in toluene with a solution of cyanogen bromide to produce [{sup 3}H] desnitro-IMI (each 55 Ci/mmol). (author).

Crystallization behavior of Li2O-SiO2, Na2O-SiO2 and Na2O-CaO-SiO2 glasses; Li2O-SiO2, Na2O-SiO2, Na2O-CaO-SiO2 kei glass no kessho sekishutsu kyodo

Energy Technology Data Exchange (ETDEWEB)

Tsutsumi, K.; Otake, J.; Nagasaka, T.; Hino, M. [Tohoku University, Sendai (Japan)

1998-06-01

It has been known that crystallization of mold powder is effective on the disturbance of heat transfer between mold and solidified shell in production of middle carbon steel slabs in continuous casting process. But it has not yet been made clear which composition of mold powder is the most suitable for crystallization. The crystallization behavior of Li2O-SiO2, Na2O-SiO2 and Na2O-CaO-SiO2 glasses was observed by differential thermal analysis (DTA) and hot-thermocouple methods with DTA in the present work. As a result, addition of alkaline metal and alkaline earth metal oxides to SiO2 increased the critical cooling rate for glass formation in binary system of Li2O-SiO2 and Na2O-SiO2 and Li2O-SiO2 system crystallized easier than Na2O-SiO2 system. In ternary system of Na2O-CaO-SiO2, addition of Na2O hurried the critical cooling rate at CaO/SiO2=0.93 mass ratio, but the rate was almost constant in the composition range of more than 15 mass% Na2O. The slag of CaO/SiO2=0.93 made the rate faster than the slag of CaO/SiO2=0.47 at constant content of 10mass% Na2O. 17 refs., 10 figs., 3 tabs.

Phase relations in the M2MoO4 - Ag2MoO4 - Hf(MoO4)2 (M=Li, Na) systems

International Nuclear Information System (INIS)

Bazarova, Zh.G.; Bazarov, B.G.; Balsanova, L.V.

2002-01-01

The M 2 MoO 4 - Ag 2 MoO 4 - Hf(MoO 4 ) 2 (M=Li, Na) systems were studied by X-ray diffraction and differential thermal analyses in the subsolidus area (450 - 500 Deg C) for the first time. The formation of the binary compound with the variable composition Li 4-x Hf 1+0.2x (MoO 4 ) 4 (0 ≤ x ≤ 0.6) in the Li 2 MoO 4 - Hf(MoO 4 ) 2 system and the ternary molybdates Li 4 Ag 2 Hf(MoO 4 ) 5 (S 1 ) and Na 2 Ag 2 Hf(MoO 4 ) 4 (S 2 ) was established and the thermal characteristics of the prepared compounds were examined. The new binary molybdate Ag 2 Hf(MoO 4 ) 3 was prepared by the reaction between Ag 2 MoO 4 and Hf(MoO 4 ) 2 [ru

Nano-glass ceramic cathodes for Li+/Na+ mixed-ion batteries

DEFF Research Database (Denmark)

He, Wen; Zhang, Xudong; Jin, Chao

2017-01-01

reactions, and the influences of molar ratio of Fe/V on the structure and electrochemical properties of NGCs. This nanoscale design offers a new possibility improved the electrochemical performances of Li+/Na+ mixed-ion batteries (LNMIBs). The NGCs-3 electrode exhibits a higher discharge capacity (145 mAh g...

The tin-rich copper lithium stannides: Li3Cu6Sn4 and Li2CuSn2

International Nuclear Information System (INIS)

Fuertauer, Siegfried; Flandorfer, Hans; Effenberger, Herta S.

2015-01-01

The Sn rich ternary intermetallic compounds Li 3 Cu 6 Sn 4 (CSD-427097) and Li 2 CuSn 2 (CSD-427098) were synthesized from the pure elements by induction melting and annealing at 400 C. Structural investigations were performed by powder- and single-crystal XRD. Li 3 Cu 6 Sn 4 crystallizes in space group P6/mmm; it is structurally related to but not isotypic with MgFe 6 Ge 6 (a = 5.095(2) Aa, c = 9.524(3) Aa; wR 2 = 0.059; 239 unique F 2 -values, 17 free variables). Li 3 Cu 6 Sn 4 is characterized by two sites with a mixed Cu:Sn occupation. In contrast to all other Cu-Li-Sn compounds known so far, any mixed occupation was found for Cu-Li pairs only. In addition, one Li site is only half occupied. The second Sn rich phase is Li 2 CuSn 2 (space group I4 1 /amd, a = 4.4281(15) Aa, c = 19.416(4) Aa; wR 2 = 0.033; 213 unique F 2 -values, 12 atom free variables); it is the only phase in the Cu-Li-Sn system which is noted for full ordering. Both crystal structures exhibit 3D-networks which host Li atoms in channels. They are important for understanding the lithiation mechanism in Cu-Sn electrodes for Li-ion batteries.

Low-energy cross sections of the BBN reaction d({alpha},{gamma}){sup 6}Li by Coulomb dissociation of {sup 6}Li

Energy Technology Data Exchange (ETDEWEB)

Heil, Michael; Suemmerer, Klaus [GSI Darmstadt (Germany); Hammache, Fairouz [IPN Orsay (France); Galaviz, Daniel [TU Darmstadt (Germany); Typel, Stefan [GANIL Caen (France)

2008-07-01

The primordial abundances of D, ({sup 3}He), {sup 4}He, and {sup 7}Li can be used to infer the baryon density of the Universe based on the framework of Big-Bang Nucleosynthesis (BBN). By precision measurements of the cosmic microwave background (CMB) an independent method became available recently. This lead to a renewed interest for BBN. Together with the recent observation of {sup 6}Li in old stars and the problems to reconcile calculated primordial {sup 7}Li abundances with those predicted on the basis of CMB results, the production of both, {sup 6}Li and {sup 7}Li in BBN has been reinvestigated. One important ingredient is the low-energy S-factor of the d-alpha radiative-capture reaction. Up to now, the only available experimental result by Kiener et al. (1991) introduced an uncertainty of about a factor of 20 in the {sup 6}Li yield. We have therefore reinvestigated the d-alpha reaction with the help of Coulomb dissociation (CD) of {sup 6}Li at 150 MeV/nucleon at GSI. CD is the only practical way to study the low-energy S-factor (which involves l=2 multipolarity) due to the large number of E2 photons contained in the equivalent-photon flux. Preliminary results indicate a drop of the S-factor as predicted by theory, contrary to the constant low-energy S-factor resulting from the previous study.

Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions

DEFF Research Database (Denmark)

Poel, Mike van der; Nielsen, C.V.; Rybaltover, M.

2002-01-01

We measure angle differential cross sections (DCS) in Li+ + Na --> Li + Na+ electron transfer collisions in the 2.7-24 keV energy range. We do this with a newly constructed apparatus which combines the experimental technique of cold target recoil ion momentum spectroscopy with a laser-cooled target...... of the de Broglie wavelength lambda(dB) = 150 fm at a velocity v = 0.20 au and the effective atomic diameter for electron capture 2R = 20 au. Parallel AO and MO semiclassical coupled-channel calculations of the Na(3s, 3p) --> Li(2s, 2p) state-to-state collision amplitudes have been performed, and quantum...

The effect of positronium formation in e+ -Li and e+ -Na scattering

International Nuclear Information System (INIS)

Adhikari, S.K.; Ghosh, A.S.; Ray, H.

1994-02-01

The e + -Li and e + -Na scattering are studied, using the close coupling approximation in the static and coupled static expansion schemes. The effect of the positronium formation on the elastic channel is found to be strong in both cases. In the case of the lithium atom the effect is dramatic; the inclusion of the positronium formation channels transforms the purely repulsive effective e + -Li S wave (static) potential to a predominantly attractive (coupled static) potential. In this case, in the static model δ(0) - δ(∞) = π. According to Levinson's theorem this suggests the presence of a S wave bound or continuum bound state in the e + -Li system. (author)

Study of the 6Li(p,π+)7Li reaction at 600 MeV

International Nuclear Information System (INIS)

Bauer, T.; Beurtey, R.; Boudard, A.; Bruge, G.; Chaumeaux, A.; Couvert, P.; Duhm, H.H.; Garreta, D.; Matoba, M.; Terrein, Y.; Aslanides, E.; Bertini, R.; Brochard, F.; Gorodetzky, Ph.; Hibou, F.; Bimbot, L.; Le Bornec, Y.; Tatischeff, B.; Dillig, M.

1977-01-01

The positive pion production through the 6 Li(p,π + ) reaction at 600 MeV has been studied using the high-resolution magnetic spectrometer SPES I. Differential cross sections have been measured from 5 0 to 35 0 sub(lab). The 6 Li(p,π + ) reaction feeds preferentially the 4.63 MeV 7/2 - level of 7 Li. The results of a calculation based on two- and three-nucleon diagrams with π and rho exchange between the projectile and a bound nucleon are also presented. (Auth.)

Improved Dehydrogenation Properties of 2LiNH2-MgH2 by Doping with Li3AlH6

Directory of Open Access Journals (Sweden)

Shujun Qiu

2017-01-01

Full Text Available Doping with additives in a Li-Mg-N-H system has been regarded as one of the most effective methods of improving hydrogen storage properties. In this paper, we prepared Li3AlH6 and evaluated its effect on the dehydrogenation properties of 2LiNH2-MgH2. Our studies show that doping with Li3AlH6 could effectively lower the dehydrogenation temperatures and increase the hydrogen content of 2LiNH2-MgH2. For example, 2LiNH2-MgH2-0.1Li3AlH6 can desorb 6.43 wt % of hydrogen upon heating to 300 °C, with the onset dehydrogenation temperature at 78 °C. Isothermal dehydrogenation testing indicated that 2LiNH2-MgH2-0.1Li3AlH6 had superior dehydrogenation kinetics at low temperature. Moreover, the release of byproduct NH3 was successfully suppressed. Measurement of the thermal diffusivity suggests that the enhanced dehydrogenation properties may be ascribed to the fact that doping with Li3AlH6 could improve the heat transfer for solid–solid reaction.

Recent Progress in Graphite Intercalation Compounds for Rechargeable Metal (Li, Na, K, Al)-Ion Batteries.

Science.gov (United States)

Xu, Jiantie; Dou, Yuhai; Wei, Zengxi; Ma, Jianmin; Deng, Yonghong; Li, Yutao; Liu, Huakun; Dou, Shixue

2017-10-01

Lithium-ion batteries (LIBs) with higher energy density are very necessary to meet the increasing demand for devices with better performance. With the commercial success of lithiated graphite, other graphite intercalation compounds (GICs) have also been intensively reported, not only for LIBs, but also for other metal (Na, K, Al) ion batteries. In this Progress Report, we briefly review the application of GICs as anodes and cathodes in metal (Li, Na, K, Al) ion batteries. After a brief introduction on the development history of GICs, the electrochemistry of cationic GICs and anionic GICs is summarized. We further briefly summarize the use of cationic GICs and anionic GICs in alkali ion batteries and the use of anionic GICs in aluminium-ion batteries. Finally, we reach some conclusions on the drawbacks, major progress, emerging challenges, and some perspectives on the development of GICs for metal (Li, Na, K, Al) ion batteries. Further development of GICs for metal (Li, Na, K, Al) ion batteries is not only a strong supplement to the commercialized success of lithiated-graphite for LIBs, but also an effective strategy to develop diverse high-energy batteries for stationary energy storage in the future.

Organic anodes and sulfur/selenium cathodes for advanced Li and Na batteries

Science.gov (United States)

Luo, Chao

To address energy crisis and environmental pollution induced by fossil fuels, there is an urgent demand to develop sustainable, renewable, environmental benign, low cost and high capacity energy storage devices to power electric vehicles and enhance clean energy approaches such as solar energy, wind energy and hydroenergy. However, the commercial Li-ion batteries cannot satisfy the critical requirements for next generation rechargeable batteries. The commercial electrode materials (graphite anode and LiCoO 2 cathode) are unsustainable, unrenewable and environmental harmful. Organic materials derived from biomasses are promising candidates for next generation rechargeable battery anodes due to their sustainability, renewability, environmental benignity and low cost. Driven by the high potential of organic materials for next generation batteries, I initiated a new research direction on exploring advanced organic compounds for Li-ion and Na-ion battery anodes. In my work, I employed croconic acid disodium salt and 2,5-Dihydroxy-1,4-benzoquinone disodium salt as models to investigate the effects of size and carbon coating on electrochemical performance for Li-ion and Na-ion batteries. The results demonstrate that the minimization of organic particle size into nano-scale and wrapping organic materials with graphene oxide can remarkably enhance the rate capability and cycling stability of organic anodes in both Li-ion and Na-ion batteries. To match with organic anodes, high capacity sulfur and selenium cathodes were also investigated. However, sulfur and selenium cathodes suffer from low electrical conductivity and shuttle reaction, which result in capacity fading and poor lifetime. To circumvent the drawbacks of sulfur and selenium, carbon matrixes such as mesoporous carbon, carbonized polyacrylonitrile and carbonized perylene-3, 4, 9, 10-tetracarboxylic dianhydride are employed to encapsulate sulfur, selenium and selenium sulfide. The resulting composites exhibit

The phase transformation and crystallization kinetics of (1 - x)Li2O-xNa2O-Al2O3-4SiO2 glasses

International Nuclear Information System (INIS)

Wang, Moo-Chin; Li, Wang-Long; Cheng, Chih-Wei; Chang, Kuo-Ming; Chen, Yong-Feng; Hsi, Chi-Shiung

2010-01-01

The phase transformation and crystallization kinetics of (1 - x)Li 2 O-xNa 2 O-Al 2 O 3 -4SiO 2 glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na 2 O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na 2 O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 ± 22.2 to 284.0 ± 10.8 kJ mol -1 when the Na 2 O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 ± 10.8 to 446.0 ± 23.2 kJ mol -1 when the Na 2 O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li 2 O-xNa 2 O-Al 2 O 3 -4SiO 2 glasses.

Terahertz reflection spectroscopy of aqueous NaCl and LiCl solutions

DEFF Research Database (Denmark)

Jepsen, Peter Uhd; Merbold, Hannes

2010-01-01

frequencies. Whereas both the real and imaginary part of the permittivity of NaCl increases with concentration,we see that the imaginary part of the permittivity of LiCl (related to the absorption)decreases with increasing salt concentration. We relate these changes to the behavior...

Electrokinetic properties of tantalum oxide deposited on model substrate in NaCl and LiCl solutions

International Nuclear Information System (INIS)

Sidorova, M.P.; Bogdanova, N.F.; Ermakova, L.Eh.; Bobrov, P.V.

1997-01-01

Electrokinetic characteristics of tantalum oxide have been studied using a model system - a plane-parallel capillary in chloride solutions containing monocharge (H + , Na + , Li + ) counterions in a wide range of pH and concentrations. It is shown that position of isoelectric point (IEP) of Ta 2 O 5 depends on concentration and type of counterion, moreover, the dependence is not explained in the framework of classical notions of the influence of counterion specific adsorption on IEP position. Electrokinetic potential of Ta 2 O-5 surface at the background of diluted LiCl solutions is higher in its absolute value, than at the background of NaCl solutions according to direct lyotropic series. The results of measurements of the capillary resistance dependence on pH at the background of NaCl and LiCl solutions 10 -3 -10 -1 M are used for the calculation of efficiency and specific surface conductivity factors

The cosmic 6Li and 7Li problems and BBN with long-lived charged massive particles

International Nuclear Information System (INIS)

Karsten, Jedamzik

2007-01-01

Charged massive particles (CHAMPs), when present during the Big Bang nucleosynthesis (BBN) era, may significantly alter the synthesis of light elements when compared to a standard BBN scenario. This is due to the formation of bound states with nuclei. This paper presents a detailed numerical and analytical analysis of such CHAMP BBN. All reactions important for predicting light-element yields are calculated within the Born approximation. Three prior neglected effects are treated in detail: (a) photo destruction of bound states due to electromagnetic cascades induced by the CHAMP decay, (b) late-time efficient destruction/production of H 2 , Li 6 , and Li 7 due to reactions on charge Z = 1 nuclei bound to CHAMPs, and (c) CHAMP exchange between nuclei. Each of these effects may induce orders-of-magnitude changes in the final abundance yields. The study focusses on the impact of CHAMPs on a possible simultaneous solution of the Li 6 and Li 7 problems. It is shown that a prior suggested simultaneous solution of the Li 6 and Li 7 problems for a relic decaying at τ x ∼ 1000 s is only very weakly dependent on the relic being neutral or charged, unless its hadronic branching ratio is B h -4 very small. By use of a Monte-Carlo analysis it is shown that within CHAMP BBN the existence of further parameter space for a simultaneous solution of the Li 6 and Li 7 problem for long decay times τ x ≥ 10 6 s seems possible but fairly unlikely. (author)

Partial exchange of the Li+, Na+ and K+ alkaline cations in the HNi(PO4).H2O layered compound

International Nuclear Information System (INIS)

Escobal, Jaione; Mesa, Jose; Pizarro, Jose; Bazan, Begona; Arriortua, Maria; Rojo, Teofilo

2006-01-01

The exchange of the Li + (1), Na + (2) and K + (3) alkaline cations in the layered HNi(PO 4 ).H 2 O was carried out starting from a methanolic solution containing the Li(OH).H 2 O hydroxide for (1) and the M(OH) (M=Na and K) hydroxides together with the (C 6 H 13 NH 2 ) 0.75 HNiPO 4 .H 2 O phases for (2) and (3). The compounds are stable until, approximately, 280 o C for (1) and 400 deg. C for phases (2) and (3), respectively. The IR spectra show the bands belonging to the water molecule and the (PO 4 ) 3- oxoanion. The diffuse reflectance spectra indicate the existence of Ni(II), d 8 , cations in slightly distorted octahedral geometry. The calculated Dq and Racah (B and C) parameters have a mean value of Dq=765, B=905 and C=3895cm -1 , respectively, in accordance with the values obtained habitually for this octahedral Ni(II) cation. The study of the exchange process performed by X-ray powder diffraction indicates that the exchange of the Li + cation in the lamellar HNi(PO 4 ).H 2 O phase is the minor rapid reaction, whereas the exchange of the Na + and K + cations needs the presence of the intermediate (C 6 H 13 NH 2 ) 0.75 HNiPO 4 .H 2 O intercalate in order to obtain the required product with the sodium and potassium ions. The Scanning electronic microscopy (SEM) images show a mean size of particle of 5μm. The Li + exchanged compound exhibits small ionic conductivity (Ωcm -1 is in the 10 -8 -10 -9 range) probably restrained by the methanol solvent. Magnetic measurements carried out from 5K to room temperature indicate antiferromagnetic coupling as the major interaction in the three phases. Notwithstanding the Li and K phases show a weak ferromagnetism at low temperatures

Crystal growth and evaluation of scintillation properties of Eu and alkali-metal co-doped LiSrAlF{sub 6} single crystals for thermal neutron detector

Energy Technology Data Exchange (ETDEWEB)

Wakahara, Shingo; Yokota, Yuui; Yamaji, Akihiro; Fujimoto, Yutaka; Sugiyama, Makoto; Kurosawa, Shunsuke [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Pejchal, Jan [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Institute of Physics AS CR, Cukrovarnicka 10, Prague 16253 (Czech Republic); Kawaguchi, Noriaki [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Tokuyama, Co. Ltd., Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 (Japan); Fukuda, Kentaro [Tokuyama, Co. Ltd., Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

2012-12-15

In recent work, Na co-doping have found to improve the light output of Eu doped LiCaAlF{sub 6} (Eu:LiCAF) for thermal neutron scintillator. We grew Eu 2% and alkali metal 1% co-doped LiSAF crystals by Micro-Pulling down method to understand the effect of alkali metal co-doping on scintillation properties and mechanism compared with LiCAF. In photo- and {alpha}-ray induced radio-luminescence spectra of the all grown crystals, the emissions from d-f transition of Eu{sup 2+} were observed. Without relation to excitation source, decay times of co-doped LiSAF were longer than Eu only doped one. The light yield of Na, K and Cs co-doped LiSAF under {sup 252}Cf neutron excitation were improved. Especially, K co-doped Eu:LiSAF reached 33200 ph/n, which outperformed Eu only doped one by approximately 20% (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Neutron flux measurement with 6Li and 7Li dual glass scintillators by γ compensation method

International Nuclear Information System (INIS)

Ji Changsong; Zhang Shulan; Zhang Shuheng

1996-01-01

Based on the characteristics of 6 Li glass scintillator which is sensitive to both neutron and gamma rays, and 7 Li glass scintillator which is sensitive to gamma rays only, a new method of detecting weak neutron flux under interference of strong gamma radiation has been investigated by means of 6 Li- 7 Li pair glass scintillator gamma compensation method. The result of neutron flux measurement by above-mentioned method with an error of about 1% when the gamma ray interference is up to 18.7% has been obtained

Neutron flux measurement with 6Li and 7Li dual glass scintillators by γ compensation method

International Nuclear Information System (INIS)

Ji Changsong; Zhang Shulan; Zhang Shuheng

1998-01-01

Based on the characteristics of 6 Li glass scintillator which is sensitive to both neutron and gamma rays, and 7 Li glass scintillator which is sensitive to gamma rays only, a new method of detecting weak neutron flux under interference of strong gamma radiation has been investigated by mans of 6 Li- 7 Li dual glass scintillator gamma compensation method. The result of neutron flux measurement by above-mentioned method with an error of about 1% when the gamma ray interference is up to 18.7% has been obtained

6Li-doped silicate glass for thermal neutron shielding

International Nuclear Information System (INIS)

Stone, C.A.; Blackburn, D.H.; Kauffman, D.A.; Cranmer, D.C.; Olmez, I.

1994-01-01

Glass formulations are described that contain high concentrations of 6 Li and are suitable for use as thermal neutron shielding. One formulation contained 31 mol% of 6 Li 2 O and 69 mol% of SiO 2 . Studies were performed on a second formulation that contained as much as 37 mol% of 6 Li 2 O and 59 mol% of SiO 2 , with 4 mol% Al 2 O 3 added to prevent crystallization at such high 6 Li 2 O concentrations. These lithium silicate glasses can be formed into a variety of shapes using conventional glass fabrication techniques. Examples include flat plates, disks, hollow cylinders, and other more complex geometries. Both in-beam and in-core experiments have been performed to study the use and durability of Li silicate glasses. In-core experiments show the glass can withstand the intense radiation fields near the core of a reactor. The neutron attenuation of the glasses used in these studies was 90%/mm. In-beam studies show that the glass is effective for reducing the gamma-ray and neutron fields near experiments. ((orig.))

The interstellar lithium abundance and the 7Li/6Li ratio

International Nuclear Information System (INIS)

Ferlet, R.; Dennefeld, M.

1985-01-01

The λ 6708 doublet of interstellar Li I has been observed at high spectral resolution (3.km s -1 ) and very good signal to noise ratio (∼ 4000) towards δ Sco and ζ Oph. Using a profile fitting method, we derive for the first time outside the solar system a 7 Li/ 6 Li ratio of 38 for a diffuse cloud in front of ζ Oph. Even the lower limit of the error bar is incompatible with the ratio measured in meteorites and is not explained by recent models of galactic evolution. The existence of a local inhomogeneity is suggested. Finally, as for other alkalis, lithium is depleted on to dust grains in the diffuse interstellar medium [fr

Puzzle of the 6Li Quadrupole Moment: Steps toward Solving It

International Nuclear Information System (INIS)

Blokhintsev, L.D.; Kukulin, V.I.; Pomerantsev, V.N.

2005-01-01

The problem of the origin of the quadrupole deformation in the 6 Li ground state is investigated with allowance for the three-deuteron component of the 6 Li wave function. Two long-standing puzzles related to the tensor interaction in the 6 Li nucleus are known: that of an anomalous smallness of the 6 Li quadrupole moment (being negative, it is smaller in magnitude than the 7 Li quadrupole moment by a factor of 5) and that of an anomalous behavior of the tensor analyzing power T 2q in the scattering of polarized 6 Li nuclei on various targets. It is shown that a large (in magnitude) negative exchange contribution to the 6 Li quadrupole moment from the three-deuteron configuration cancels almost completely the 'direct' positive contribution due to the αd folding potential. As a result, the total quadrupole moment proves to be close to zero and highly sensitive to fine details of the tensor nucleon-nucleon interaction in the 4 He nucleus and of its wave function

The Watanabe model for 6Li-nucleus optical potential

International Nuclear Information System (INIS)

Abul-Magd, A.Y.; Rabie, A.; El-Gazzar, M.A.

1980-09-01

Optical potentials for the scattering of 6 Li projectiles are calculated using the Watanabe model and an α+d cluster model wave function for 6 Li. Reasonable fits to the elastic differential cross-section and vector polarization are obtained. (author)

Quantum-chemical study of structure and stability of hydride complexes Li4BeH6 and Li4MgH6

International Nuclear Information System (INIS)

Zyubin, A.S.; Charkin, O.P.; Klabo, D.A.; Shlojfer, P.R.

1993-01-01

Nonempirical calculations of geometrical structure, electronic structure and relative energies of a wide range of different configurations of Li 4 MH 6 (M = Be, Mg) molecules were conducted in order to predict the existence of complex hydrides with high hydrogen content. It was revealed, that Li 4 MH 6 molecules were stable to decomposition and could exist in isolated state or in inert matrices. Li 4 MH 6 systems are noted for existence of several isomers with energy, close to the basic structure. The presence of M atoms with coordination number (CN) equal to four is considered to be their common feature. The structure, where CN of Be and Mg is equal to three, are less stable. Configurations, including M atoms with CN = 5 or 6, are much more unfavorable from the viewpoint of energy

Density functional theory studies on theelectronic, structural, phonon dynamicaland thermo-stability properties of bicarbonates MHCO3, M D Li, Na, K

Energy Technology Data Exchange (ETDEWEB)

Duan, Yuhua; Zhang, Bo; Sorescu, Dan C.; Johnson, Karl; Majzoub, Eric H; Luebke, David R.

2012-07-01

The structural, electronic, phonon dispersion and thermodynamic properties of MHCO3 (M D Li, Na, K) solids were investigated using density functional theory. The calculated bulk properties for both their ambient and the high-pressure phases are in good agreement with available experimental measurements. Solid phase LiHCO3 has not yet been observed experimentally. We have predicted several possible crystal structures for LiHCO3 using crystallographic database searching and prototype electrostatic ground state modeling. Our total energy and phonon free energy .FPH/ calculations predict that LiHCO3 will be stable under suitable conditions of temperature and partial pressures of CO2 and H2O. Our calculations indicate that the HCO 3 groups in LiHCO3 and NaHCO3 form an infinite chain structure through O H O hydrogen bonds. In contrast, the HCO 3 anions form dimers, .HCO 3 /2, connected through double hydrogen bonds in all phases of KHCO3. Based on density functional perturbation theory, the Born effective charge tensor of each atom type was obtained for all phases of the bicarbonates. Their phonon dispersions with the longitudinal optical–transverse optical splitting were also investigated. Based on lattice phonon dynamics study, the infrared spectra and the thermodynamic properties of these bicarbonates were obtained. Over the temperature range 0–900 K, the FPH and the entropies (S) of MHCO3 (M D Li, Na, K) systems vary as FPH.LiHCO3/ > FPH.NaHCO3/ > FPH.KHCO3/ and S.KHCO3/ > S.NaHCO3/ > S.LiHCO3/, respectively, in agreement with the available experimental data. Analysis of the predicted thermodynamics of the CO2 capture reactions indicates that the carbonate/bicarbonate transition reactions for Na and K could be used for CO2 capture technology, in agreement with experiments.

Fast neutron measurements with 7Li and 6Li enriched CLYC scintillators

International Nuclear Information System (INIS)

Giaz, A.; Blasi, N.; Boiano, C.; Brambilla, S.; Camera, F.; Cattadori, C.; Ceruti, S.; Gramegna, F.; Marchi, T.; Mattei, I.; Mentana, A.; Million, B.; Pellegri, L.; Rebai, M.; Riboldi, S.; Salamida, F.; Tardocchi, M.

2016-01-01

The recently developed Cs 2 LiYCl 6 :Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (<5% at 662 keV) but also for their capability to identify and measure the energy of both gamma rays and fast/thermal neutrons. The thermal neutrons were detected by the 6 Li(n,α)t reaction while for the fast neutrons the 35 Cl(n,p) 35 S and 35 Cl(n,α) 32 P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9–3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on 35 Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a 7 LiF target. We tested a CLYC detector 6 Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector 7 Li-enriched at more than 99%, which is suitable for fast neutron measurements.

The kinetic and mechanistic aspects of the oxidative dehydrogenation of ethane over Li/Na/MgO catalysts

NARCIS (Netherlands)

Swaan, H.M.; Swaan, H.M.; Toebes, A.; Toebes, A.; van Ommen, J.G.; Seshan, Kulathuiyer; Ross, J.R.H.; Ross, J.R.H.

1992-01-01

Kinetic and mechanistic aspects of the oxidative dehydrogenation of ethane catalysed by Li/MgO and Li/Na/MgO have been investigated. Initial rate measurements at 600°C; revealed that the Li/MgO catalyst produced C2H4, CO2, CO and H2 by parallel reactions whereas the sodium-promoted catalyst produced

Nuclear spin polarized alkali beams (Li and Na): Production and acceleration

International Nuclear Information System (INIS)

Jaensch, H.; Becker, K.; Blatt, K.; Leucker, H.; Fick, D.

1987-01-01

Recent improvements of the Heidelberg source for polarized heavy ions (PSI) are described. By means of optical pumping in combination with the existing multipole separation magnet the beam figure of merit (polarization 2 x intensity) was doubled. 7 Li and 23 Na atomic beams can now be produced in pure hyperfine magnetic substates. Fast switching of the polarization is achieved by an adiabatic medium field transition. The hyperfine magnetic substate population is determined by laser-induced fluorescence spectroscopy. In routine operation atomic beams with nuclear polarization p α ≥0.85 (α=z, zz) are obtained. The acceleration of polarized 23 Na - ions by a 12 MV tandem accelerator introduces a new problem: the energy at the terminal stripper foil is not sufficient to produce a usable yield of naked ions. For partially stripped ions hyperfine interaction of the remaining electrons with the nuclear spin reduces the nuclear polarization. Using in addition the Heidelberg postaccelerator 23 Na 9+ beams of energies between 49 and 184 MeV were obtained with an alignment on target of P zz ≅0.45. 7 Li beams have also been accelerated up to 45 MeV with an alignment of P zz =0.69. (orig.)

Recent Progress in Graphite Intercalation Compounds for Rechargeable Metal (Li, Na, K, Al)‐Ion Batteries

Science.gov (United States)

Xu, Jiantie; Dou, Yuhai; Wei, Zengxi; Li, Yutao; Liu, Huakun; Dou, Shixue

2017-01-01

Abstract Lithium‐ion batteries (LIBs) with higher energy density are very necessary to meet the increasing demand for devices with better performance. With the commercial success of lithiated graphite, other graphite intercalation compounds (GICs) have also been intensively reported, not only for LIBs, but also for other metal (Na, K, Al) ion batteries. In this Progress Report, we briefly review the application of GICs as anodes and cathodes in metal (Li, Na, K, Al) ion batteries. After a brief introduction on the development history of GICs, the electrochemistry of cationic GICs and anionic GICs is summarized. We further briefly summarize the use of cationic GICs and anionic GICs in alkali ion batteries and the use of anionic GICs in aluminium‐ion batteries. Finally, we reach some conclusions on the drawbacks, major progress, emerging challenges, and some perspectives on the development of GICs for metal (Li, Na, K, Al) ion batteries. Further development of GICs for metal (Li, Na, K, Al) ion batteries is not only a strong supplement to the commercialized success of lithiated‐graphite for LIBs, but also an effective strategy to develop diverse high‐energy batteries for stationary energy storage in the future. PMID:29051856

Transport properties of molten-salt reactor fuel mixtures: the case of Na, Li, Be/F and Li, Be, Th/F salts

International Nuclear Information System (INIS)

Ignatiev, V.; Merzlyakov, A.; Afonichkin, V.; Khokhlov, V.; Salyulev, A.

2003-01-01

In this paper we have compiled transport properties information, available, on two types of FLiBe based salt mixtures (Na,Li,Be/F and Li,Be,Th/F) that are presently of importance in the design of innovative molten-salt burner reactors. Estimated and/or experimental values measured (particularly, from prior US and Russian studies, as well our recent studies) are given for the following properties: viscosity, thermal conductivity, phase transition behaviour, heat capacity, density and thermal expansion. (author)

Transport properties of molten-salt reactor fuel mixtures: the case of Na, Li, Be/F and Li, Be, Th/F salts

Energy Technology Data Exchange (ETDEWEB)

Ignatiev, V; Merzlyakov, A [Kurchatov Institute - KI (Russian Federation); Afonichkin, V; Khokhlov, V; Salyulev, A [Institute of High Temperature Electrochemisty (IHTE), RF Yuri Golovatov, Konstantin Grebenkine, Vladimir Subbotin Institute of Technical Physics (VNIITF) (Russian Federation)

2003-07-01

In this paper we have compiled transport properties information, available, on two types of FLiBe based salt mixtures (Na,Li,Be/F and Li,Be,Th/F) that are presently of importance in the design of innovative molten-salt burner reactors. Estimated and/or experimental values measured (particularly, from prior US and Russian studies, as well our recent studies) are given for the following properties: viscosity, thermal conductivity, phase transition behaviour, heat capacity, density and thermal expansion. (author)

Thermal analysis and phase diagrams of the LiF BiF{sub 3} e NaF BiF{sub 3} systems; Analise termica e diagramas de fase dos sistemas LiF-BiF{sub 3} e NaF-BiF{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Gerson Hiroshi de Godoy

2013-07-01

Investigations of the binary systems LiF-BiF{sub 3} and NaF-BiF{sub 3} were performed with the objective of clarifying the thermal behavior and phase equilibria of these systems and their intermediary phases, an important requisite for high-quality crystal growth. Several samples in the entire range of compositions (0 to 100 mol% BiF{sub 3}) of both systems were subjected to experiments of differential thermal analysis (DTA) and thermogravimetry (TG), and also of differential scanning calorimetry (DSC). A few specific compositions were selected for X-ray diffraction to supplement the experimental data. Due to the high vulnerability of BiF{sub 3} to oxygen contamination, its volatility and propensity to destroy metal parts upon heating, it was necessary to determine the optimal conditions for thermal analysis before investigating the systems themselves. Phase relations in the system LiF-BiF{sub 3} were completely clarified and a phase diagram was calculated and evaluated via the commercial software Factsage. The diagram itself consists in a simple peritectic system in which the only intermediary compound, LiBiF{sub 4}, decomposes into LiF and a liquid phase. The NaF-BiF{sub 3} system could not be completely elucidated and the phase relations in the NaF poor side (> 50% BiF{sub 3}) are still unknown. In the NaF rich side, however, the possible peritectoid decomposition of the compound NaBiF{sub 4} was identified. In both systems X-ray diffraction yielded crystal structures discrepant with the literature for the intermediary phases, LiBiF{sub 4}, NaBiF{sub 4} and a solid solution of NaF and BiF{sub 3} called {sup I.} The observed structures remain unknown and explanations for the discrepancies were proposed. (author)

Crystallization behavior of (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses

Energy Technology Data Exchange (ETDEWEB)

Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Cheng, Chih-Wei; Chang, Kuo-Ming [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.t [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

2010-07-02

The crystallization behavior of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of {beta}-spodumene. The isothermal crystallization kinetics of {beta}-spodumene from the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of {beta}-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na{sub 2}O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses.

Technology of preparation for low density 6Li(H,D) solid micro-target

International Nuclear Information System (INIS)

Wang Xisheng; Zeng Jiaquan; Li Qiang

2002-01-01

Low density 6 Li(H,D) micro-targets are prepared by loose sintering 6 LiH or 6 LiD powder in a tiny gold cylinder and soaking for 30 min up to 430 degree C at the rate of 10 degree C/h in argon. The dimension of the micro-targets is as tiny as 0.6-1.0 mm for diameter and 1-2 mm for length. Densities of 6 LiH and 6 LiD without Parylene C is (0.283 +- 0.009) g/cm 3 and (0.369 +- 0.009) g/cm 3 , respectively while 6 LiD targets with Parylene C is only (0.301 +- 0.010) g/cm 3 . The Parylene C has no effect on purity, deuterium abundance and 6 Li abundance of the sintered micro-targets. It's effective to keep 6 Li(H,D) purity by strict control of argon atmosphere

Electrochemical behavior of boron in LiF-NaF-KF- melts

DEFF Research Database (Denmark)

Polyakova, L.P.; Bukatova, G.A.; Polyakova, E.G.

1996-01-01

The electrochemical reduction of B(III) to B(0) in KBF4-LiF-NaF-KF melts has been studied by voltammetric and chronopotentiometric methods, Glassy carbon, Pt, and Ag were used as working electrode materials. Only in the case of Ag was the reduction not complicated by interaction between boron...

NaLaTi_2O_6 nanosheet as a potential anode material for lithium ion batteries

International Nuclear Information System (INIS)

Geng, Qiao; Cao, Liyun; Kong, Xingang; Xu, Zhanwei; Huang, Jianfeng; Li, Jiayin; Cheng, Yayi

2016-01-01

Highlights: • NaLaTi_2O_6 nanosheet was achieved by a simple one-step hydrothermal method. • NaLaTi_2O_6 was reported for the first time as an anode material. • NaLaTi_2O_6 shown a high discharge capacity of about 180 mAh/g at 100 mA/g. - Abstract: NaLaTi_2O_6 nanosheet was achieved by one-step hydrothermal method and was reported for the first time as an anode material for lithium ion batteries. The phase structure and morphology analysis reveals that pure pervoskite NaLaTi_2O_6 possesses nanosheet morphology with thickness of about 20 nm and length of several hundred nanometers. The electrochemical performances demonstrate that NaLaTi_2O_6 has a good lithium ion insertion/extraction ability with a discharge capacity of about 180 mAh/g, which is slightly larger than Li_4Ti_5O_1_2 theoretical capacity (175 mAh/g). Even more, after 1000 charge-discharge cycles at 100 mA/g, it still maintains a discharge capacity of 165 mAh/g, suggesting that NaLaTi_2O_6 could be explored as a potential anode material for lithium ion batteries.

Thermal analysis and phase diagrams of the LiF BiF3 e NaF BiF3 systems

International Nuclear Information System (INIS)

Nakamura, Gerson Hiroshi de Godoy

2013-01-01

Investigations of the binary systems LiF-BiF 3 and NaF-BiF 3 were performed with the objective of clarifying the thermal behavior and phase equilibria of these systems and their intermediary phases, an important requisite for high-quality crystal growth. Several samples in the entire range of compositions (0 to 100 mol% BiF 3 ) of both systems were subjected to experiments of differential thermal analysis (DTA) and thermogravimetry (TG), and also of differential scanning calorimetry (DSC). A few specific compositions were selected for X-ray diffraction to supplement the experimental data. Due to the high vulnerability of BiF 3 to oxygen contamination, its volatility and propensity to destroy metal parts upon heating, it was necessary to determine the optimal conditions for thermal analysis before investigating the systems themselves. Phase relations in the system LiF-BiF 3 were completely clarified and a phase diagram was calculated and evaluated via the commercial software Factsage. The diagram itself consists in a simple peritectic system in which the only intermediary compound, LiBiF 4 , decomposes into LiF and a liquid phase. The NaF-BiF 3 system could not be completely elucidated and the phase relations in the NaF poor side (> 50% BiF 3 ) are still unknown. In the NaF rich side, however, the possible peritectoid decomposition of the compound NaBiF 4 was identified. In both systems X-ray diffraction yielded crystal structures discrepant with the literature for the intermediary phases, LiBiF 4 , NaBiF 4 and a solid solution of NaF and BiF 3 called I. The observed structures remain unknown and explanations for the discrepancies were proposed. (author)

On the roles of the dopants in LiF: Mg,Cu,Na,Si thermoluminescent material

International Nuclear Information System (INIS)

Lee, J. I.; Kim, J. L.; Chang, S. Y.; Chung, K. S.; Choe, H. S.

2005-01-01

In this paper, some results of the study on the roles of the dopants in the LiF:Mg,Cu,Na,Si thermoluminescent (TL) material that was developed at the Korea Atomic Energy Research Inst. for radiation protection are presented. Although there have been many studies to investigate the roles of the dopants in LiF:Mg,Cu,P TL material in the TL process, there are some discrepancies in the understanding of the roles of Cu and P between various researchers. In case of LiF:Mg,Cu,Na,Si TL material, there are a few studies on the roles of the dopants. Three kinds of samples in each of which one dopant is excluded, and the optimised sample, were prepared for this study. The measurements and analysis of the three-dimensional TL spectra, based on the temperature, wavelength and intensity, and the glow curves for those samples are used in this study. The results show that Mg plays a role in the trapping of the charge carriers and Cu plays a role in the luminescence recombination process; however, the effect of Na and Si on the glow curve structure and the TL emission spectra is much less than that of Mg and Cu. It is considered that Na and Si each plays a role in the improvement of the luminescence efficiency. (authors)

Vapor Pressure Measurements of LiBH4, NaBH 4 and Ca(BH4)2 using Knudsen Torsion Effusion Gravimetric Method

Science.gov (United States)

Danyan, Mohammad Masoumi

Hydrogen storage is one of the critical technologies needed on the path towards commercialization for mobile applications. In the past few years, a range of new light weight hydrogen containing material has been discovered with good storage properties. Among them, lithium borohydride (LiBH 4) sodium borohydride (NaBH4) and calcium borohydride (Ca(BH 4)2) have shown promising results to be used as solid state hydrogen storage material. In this work, we have determined equilibrium vapor pressures of LiBH 4 NaBH4 and Ca(BH4)2 obtained by Torsion effusion thermogravimetric method. Results for all the three hydrides exhibited that a small fraction of the materials showed congruency, and sublimed as gaseous compound, but the majority of the material showed incongruent vaporization. Two Knudsen cells of 0.3 and 0.6mm orifice size was employed to measure the total vapor pressures. A Whitman-Motzfeldt method is used to extrapolate the measured vapor pressures to zero orifice size to calculate the equilibrium vapor pressures. In the case of LiBH4 we found that 2% of the material evaporated congruently (LiBH4(s) → LiBH4(g)) according to the equation: logPLiBH4/P 0 =-3263.5 +/-309/T + (1.079 +/-0.69) and rest as incongruent vaporization to LiH, B, and hydrogen gas according to the equation logPeq/P0 =(-3263.5 +/-309)/T+ (2.458 +/-0.69) with DeltaH evap.= 62.47+/-5.9 kJ/mol of H2, DeltaSevap. = 47.05+/-13 J/mol of H2.K. The NaBH4 also had somewhat similar behavior, with 9% congruent evaporation and equilibrium vapor pressure equation of logPLiBH4=-7700+/-335/ T+ (6.7+/-1.5) and 91% incongruent decomposition to Na and Boron metal, and hydrogen gas. The enthalpy of vaporization; DeltaHevap. = 147.2+/-6.4kJ/molH2 and DeltaSevap.= 142 +/-28 kJ/molH2.K (550-650K). The Ca(BH4) 2 exhibited similar vaporization behavior with congruency of 3.2%. The decomposition products are CaH2 and Boron metal with evolution of hydrogen gas varying with the pressure equation as logPeq /P0 =(-1562

Cation incorporation into zirconium oxide in LiOH, NaOH, and KOH solutions

International Nuclear Information System (INIS)

Jeong, Y.H.; Kim, K.H.; Baek, J.H.

1999-01-01

To investigate the cation incorporation into zirconium oxide, SIMS analysis was performed on the specimens prepared to have an equal oxide thickness in LiOH, NaOH, and KOH solutions. Even though they have an equal oxide thickness in LiOH, NaOH, and KOH solutions, the penetration depth of cation into the oxide decreased with an increase in the ionic radius of cation. The cation is considered to control the corrosion in alkali hydroxide solutions and its effect is dependent on the concentration of alkali and the oxide thickness. The slight enhancement of the corrosion rate at a low concentration is thought to be caused by cation incorporation into oxide, while the significant acceleration at a high concentration is due to the transformation of oxide microstructures that would be also induced by cation incorporation into oxide. (orig.)

Hydrogen storage properties of Na-Li-Mg-Al-H complex hydrides

International Nuclear Information System (INIS)

Tang Xia; Opalka, Susanne M.; Laube, Bruce L.; Wu Fengjung; Strickler, Jamie R.; Anton, Donald L.

2007-01-01

Lightweight complex hydrides have attracted attention for their high storage hydrogen capacity. NaAlH 4 has been widely studied as a hydrogen storage material for its favorable reversible operating temperature and pressure range for automotive fuel cell applications. The increased understanding of NaAlH 4 has led to an expanded search for high capacity materials in mixed alkali and akali/alkaline earth alanates. In this study, promising candidates in the Na-Li-Mg-Al-H system were evaluated using a combination of experimental chemistry, atomic modeling, and thermodynamic modeling. New materials were synthesized using solid state and solution based processing methods. Their hydrogen storage properties were measured experimentally, and the test results were compared with theoretical modeling assessments

Li14P2O3N6 and Li7PN4: Computational study of two nitrogen rich crystalline LiPON electrolyte materials

Science.gov (United States)

Al-Qawasmeh, Ahmad; Holzwarth, N. A. W.

2017-10-01

Two lithium oxonitridophosphate materials are computationally examined and found to be promising solid electrolytes for possible use in all solid-state batteries having metallic Li anodes - Li14P2O3N6 and Li7PN4. The first principles simulations are in good agreement with the structural analyses reported in the literature for these materials and the computed total energies indicate that both materials are stable with respect to decomposition into binary and ternary products. The computational results suggest that both materials are likely to form metastable interfaces with Li metal. The simulations also find both materials to have Li ion migration activation energies comparable or smaller than those of related Li ion electrolyte materials. Specifically, for Li7PN4, the experimentally measured activation energy can be explained by the migration of a Li ion vacancy stabilized by a small number of O2- ions substituting for N3- ions. For Li14P2O3N6, the activation energy for Li ion migration has not yet been experimentally measured, but simulations predict it to be smaller than that measured for Li7PN4.

The ion exchange properties and equilibrium constants of Li+, Na+ and K+ on zirconium phosphate highly dispersed on a cellulose acetate fibers surface

Directory of Open Access Journals (Sweden)

Borgo Claudemir Adriano

2004-01-01

Full Text Available Highly dispersed zirconium phosphate was prepared by reacting celullose acetate/ZrO2 (ZrO2 = 11 wt%, 1.0 mmol g-1 of zirconium atom per gram of the material with phosphoric acid. High power decoupling magic angle spinning (HPDEC-MAS 31P NMR and X-ray photoelectron spectroscopy data indicated that HPO4(2- is the species present on the membrane surface. The specific concentration of acidic centers, determined by ammonia gas adsorption, is 0.60 mmol g-1. The ion exchange capacities for Li+, Na+ and K+ ions were determined from ion exchange isotherms at 298 K and showed the following values (in mmol g-1: Li+= 0.05, Na+= 0.38 and K+= 0.57. Due to the strong cooperative effect, the H+/Na+ and H+/K+ ion exchange is of non ideal nature. These ion exchange equilibria were treated with the use of models of fixed tridentate centers, which consider the surface of the sorbent as polyfunctional sorption centers. Both the observed ion exchange capacities with respect to the alkaline metal ions and the equilibrium constants are discussed by taking into consideration the sequence of the ionic hydration radii for Li+, Na+ and K+. The matrix affinity for the ions decreases with increasing the cations hydration radii from K+ to Li+. The high values of the separation factors S Na+/Li+ and S K+/Li+ (up to several hundreds support the application of this material for the quantitative separation of Na+ and K+ from Li+ from a mixture containing these three ions.

Circular magnetic dichroism of the Fa center adsorption in KCl doped with Li and Na

International Nuclear Information System (INIS)

Baldacchini, G.; Botti, S.; Grassano, U.M.

1990-01-01

The spin-orbit structure of F A in KCl:Li and KCl:Na have been studied by means of the magnetic circular dichroism. Due to their C 4V , symmetry the F A centers have two different spin-orbit parameters, Δ * and Δ * , which only in the KCl:Li case follow the relation: Δ * F A centers have been determined using the method of moment

Measurements of differential cross sections for the reactions 6,7Li(n,d)5,6He and 6,7Li(n,t)4,5He at 14.1 MeV

International Nuclear Information System (INIS)

Shirato, Shoji; Hata, Kazuhiro; Ando, Yoshiaki; Shibuya, Shinji; Shibata, Keiichi.

1989-08-01

A summary of our measured cross sections for the 14.1 MeV neutron-induced reactions on lithium isotopes has been presented. Our data were measured with two counter telescopes, each of which consisted of two gas proportional counters and silicon ΔE and E detectors. Measured energy spectra of deuterons and tritons from 6 Li(n,d)n 4 He and 7 Li(n,t)n 4 He, respectively, were analyzed by a simple final-state interaction theory. Measured angular distributions for these reactions as well as 6 Li(n,t) 4 He and 7 Li(n,d) 6 He were analyzed by exact finite-range distorted wave Born approximation (EFR-DWBA) calculations. Spectroscopic factors extracted from the EFR-DWBA analyses have been compared with theoretical predictions. (author)

Polycrystalline V2O5/Na0.33V2O5 electrode material for Li+ ion redox supercapacitor

International Nuclear Information System (INIS)

Manikandan, Ramu; Justin Raj, C.; Rajesh, Murugesan; Kim, Byung Chul; Park, Sang Yeup; Cho, Bo-Bae; Yu, Kook Hyun

2017-01-01

Highlights: • Different polycrystalline V 2 O 5 /Na 0.33 V 2 O 5 nanostructures were synthesized via simple co-precipitation technique. • The various molar ratios of NaOH precipitator determine the morphology, structural and electrochemical properties of V/Na. • The equimolar ratio of reactant and precipitator shows the formation of ∼96% of pure crystalline phase of V 2 O 5 . • Li + ions intercalation and deintercalation process enhanced the specific capacitance. - Abstract: This work essentially offers a new kind of V 2 O 5 /Na 0.33 V 2 O 5 as electrochemical active material for the development of Li + ion redox supercapacitors. Here, polycrystalline mixed phase of V 2 O 5 /Na 0.33 V 2 O 5 (V/Na) nanostructures are synthesized via simple co-precipitation technique. The various molar ratio of precipitator (NaOH) in the synthesis process displays different nanostructures of V/Na. The structural and morphological properties of V/Na samples are studied using physico-chemical analysis methods. The electrochemical properties of V/Na nanostructured samples are performed using cyclic voltammetry, galvanostatic charge/discharge test and electrochemical impedance spectroscopy techniques in 1 M LiClO 4 aqueous electrolyte. The sample V/Na synthesized using equimolar ratio of vanadium salt and precipitator displayed nanopellet morphology, which exhibited the highest capacitance value of 334 Fg −1 at 1 Ag −1 discharge current density. Moreover, these polycrystalline V/Na nanostructured electrodes show excellent electrochemical properties with comparable stability after 1000 charge/discharge cycles.

Knight shift of 23Na and 7Li nuclei in liquid sodium-lithium alloys

International Nuclear Information System (INIS)

Feitsma, P.D.

1977-01-01

The Knight shift of 23 Na and 7 Li nuclei in liquid sodium-lithium alloys has been measured. Some aspects of the theoretical interpretation of the Knight shift within the diffraction model, are clarified

Calculation of the πsup(+)sup(7)Li → pesup(+)esup(-)sup(6)Li

International Nuclear Information System (INIS)

Avakov, G.V.; Blokhintsev, L.D.; Blokhintseva, T.D.

1985-01-01

The π +7 Li → p e + e -6 Li reaction have been considered in the framework of the nucleon cluster model and of the shell model. The cross section of this reaction have been calculated at the pion kinetic energy 380 MeV. The comparison with the available experimental data has been carried out

The cosmic {sup 6}Li and {sup 7}Li problems and BBN with long-lived charged massive particles

Energy Technology Data Exchange (ETDEWEB)

Karsten, Jedamzik [Montpellier-2 Univ., Lab. de Physique Mathemathique et Theorique, C.N.R.S., 34 - Montpellier (France)

2007-07-01

Charged massive particles (CHAMPs), when present during the Big Bang nucleosynthesis (BBN) era, may significantly alter the synthesis of light elements when compared to a standard BBN scenario. This is due to the formation of bound states with nuclei. This paper presents a detailed numerical and analytical analysis of such CHAMP BBN. All reactions important for predicting light-element yields are calculated within the Born approximation. Three prior neglected effects are treated in detail: (a) photo destruction of bound states due to electromagnetic cascades induced by the CHAMP decay, (b) late-time efficient destruction/production of H{sup 2}, Li{sup 6}, and Li{sup 7} due to reactions on charge Z = 1 nuclei bound to CHAMPs, and (c) CHAMP exchange between nuclei. Each of these effects may induce orders-of-magnitude changes in the final abundance yields. The study focusses on the impact of CHAMPs on a possible simultaneous solution of the Li{sup 6} and Li{sup 7} problems. It is shown that a prior suggested simultaneous solution of the Li{sup 6} and Li{sup 7} problems for a relic decaying at {tau}{sub x} {approx} 1000 s is only very weakly dependent on the relic being neutral or charged, unless its hadronic branching ratio is B{sub h} << 10{sup -4} very small. By use of a Monte-Carlo analysis it is shown that within CHAMP BBN the existence of further parameter space for a simultaneous solution of the Li{sup 6} and Li{sup 7} problem for long decay times {tau}{sub x} {>=} 10{sup 6} s seems possible but fairly unlikely. (author)

Gallium oxide nanorods as novel, safe and durable anode material for Li- and Na-ion batteries

International Nuclear Information System (INIS)

Meligrana, Giuseppina; Lueangchaichaweng, Warunee; Colò, Francesca; Destro, Matteo; Fiorilli, Sonia; Pescarmona, Paolo P.; Gerbaldi, Claudio

2017-01-01

Highlights: • Gallium oxide nanorods applied for the first time as anode material for Li-/Na-ion batteries. • Durable ambient temperature cycling (400 cycles) was observed in Li-based cells. • Stable reversible cycling (> 200 mAh g"−"1) was achieved for the first time in Na-based cells. - Abstract: Gallium oxide nanorods prepared by template-free synthesis are reported for the first time as safe and durable anode material for lithium- and sodium-ion batteries. The ambient temperature electrochemical response of the nanorods, tested by cyclic voltammetry and constant-current reversible cycling, is highly satisfying in terms of remarkable stability and capacity retention upon long-term operation (400 cycles), even at high current densities. The newly proposed application of gallium oxide nanorods as electrode material is notable also because this material can preserve the electrical pathway without the need of any “buffer matrix” to compensate for the expansion upon lithium or sodium reversible storage. The highly promising electrochemical performance is attributed to the high aspect ratio and high surface area that stem from the nanorod morphology and which can lead to short diffusion path and fast kinetics of both cations (Li"+ or Na"+) and electrons.

The puzzle of the 6Li quadrupole moment: steps toward the solution

International Nuclear Information System (INIS)

Blokhintsev, L.D.; Kukulin, V.I.; Pomerantsev, V.N.

2005-01-01

The problem of origin of the ground-state 6 Li quadrupole deformation has been investigated with account of the three-deuteron component of this nucleus wave function. two long-standing puzzles related to the tensor interaction in 6 Li are known. The first one lies in the anomalously small value of the 6 Li quadrupole moment which, being negative, is in absolute magnitude smaller by the factor of 5 than that of 6 Li. The second puzzle consists in the anomalous behavior of the tensor analyzing power T 2q in scattering of polarized 6 Li nuclei from various targets. It is shown that the large (in absolute magnitude) negative contribution to the 6 Li quadrupole moment resulting from the three-deuteron configuration cancels almost completely the direct positive contribution due to the folding αd-potential. As a result, the total quadrupole moment turns out to be close to zero and highly sensitive to fine details of the tensor NN interaction and of the 4 He wave function [ru

Studies on the thermal decomposition kinetics of LiPF6 and LiBC4O8

Indian Academy of Sciences (India)

WINTEC

ion batteries. The current electrolyte generally used in lithium-ion batteries is mainly composed of LiPF6 and a blend of alkyl carbonates. LiPF6 has been widely adopted for more than a decade, owing to its neces- sary pre-requisites for use in lithium ion batteries, for example, it is easily soluble in various solvents, can lead ...

Measurement of 6Li(n,α)3H reaction cross section

International Nuclear Information System (INIS)

Renner, C.

1979-01-01

The 6 Li(n,α) 3 H reaction cross section was measured at 12 discrete neutron energies between 80 KeV and 470 KeV by using the Oak Ridge Linear Acelerator (ORELA) as a pulsed neutron source. The neutron beam was filtered through 20 cm or 30 cm of Armco iron which produces several monoenergetic energies groups (iron windows) between 20 KeV and 1000 KeV about 2 KeV wide. The (n,α) events were detected by a 1 mm thick Li-glass scintillator and the neutron flux was measured with a NE110 plastic scintillator 6,6 cm thick and 10 cm in diameter. Multiple scattering corrections in the Li-glass and the NE110 scintillator efficiency were determined theoretically by using Monte Carlo technique. The 6 Li content in the Li-glasses was determined by transmission measurements with low energy neutrons. A theoretical fit was applied to the results by the R-matrix theory. (Author) [pt

Phase transition and piezoelectric properties of K0.48Na0.52NbO3-LiTa0.5Nb0.5O3-NaNbO3 lead-free ceramics

International Nuclear Information System (INIS)

Gao Feng; Liu Liangliang; Xu Bei; Cao Xiao; Deng Zhenqi; Tian Changsheng

2011-01-01

Highlights: → The evolution of the crystal structure for the new phase K 3 Li 2 Nb 5 O 15 was described. → The dielectric relaxor behavior would be strengthened by increasing plate-like NN. → k p and d 33 decrease with increasing amount of plate-like NN. → 0.01-0.03 mol of plate-like NN is a proper content for texturing ceramics by RTGG. - Abstract: Plate-like NaNbO 3 (NN) particles were used as the raw material to fabricate (1 - x)[0.93 K 0.48 Na 0.52 Nb O 3 -0.07Li(Ta 0.5 Nb 0.5 )O 3 ]-xNaNbO 3 lead-free piezoelectric ceramics using a conventional ceramic process. The effects of NN on the crystal structure and piezoelectric properties of the ceramics were investigated. The results of X-ray diffraction suggest that the perovskite phase coexists with the K 3 Li 2 Nb 5 O 15 phase, and the tilting of the oxygen octahedron is probably responsible for the evolution of the tungsten-bronze-typed K 3 Li 2 Nb 5 O 15 phase. The Curie temperature (T C ) is shifted to lower temperature with increasing NN content. (1 - x)[0.93 K 0.48 Na 0.52 NbO 3 -0.07Li(Ta 0.5 Nb 0.5 )O 3 ]-xNaNbO 3 ceramics show obvious dielectric relaxor characteristics for x > 0.03, and the relaxor behavior of ceramics is strengthened by increasing NN content. Both the electromechanical coupling factor (k p ) and the piezoelectric constant (d 33 ) decrease with increasing amounts of NN. 0.01-0.03 mol of plate-like NaNbO 3 in 0.93 K 0.48 Na 0.52 NbO 3 -0.07Li(Ta 0.5 Nb 0.5 )O 3 gives the optimum content for preparing textured ceramics by the RTGG method.

Electrochemical investigation of Li-Al anodes in oligo(ethylene glycol) dimethyl ether/LiPF6

International Nuclear Information System (INIS)

Zhou, Y.; Wang, X.; Lee, H.; Nam, K.; Haas, O.

2011-01-01

LiPF 6 dissolved in oligo(ethylene glycol) dimethyl ether with a molecular weight 5 g mol -1 was investigated as a new electrolyte (OEGDME5, 1 M LiPF 6 ) for metal deposition and battery applications. At 25 C a conductivity of .48 x 1 -3 S cm -1 was obtained and at 85 C, 3.78 x 1 -3 S cm -1 . The apparent activation barrier for ionic transport was evaluated to be 3.7 kJ mol -1 . OEGDME5, 1 M LiPF 6 allows operating temperature above 1 C with very attractive conductivity. The electrolyte shows excellent performance at negative and positive potentials. With this investigation, we report experimental results obtained with aluminum electrodes using this electrolyte. At low current densities lithium ion reduction and re-oxidation can be achieved on aluminum electrodes at potentials about 28 mV more positive than on lithium electrodes. In situ X-ray diffraction measurements collected during electrochemical lithium deposition on aluminum electrodes show that the shift to positive potentials is due to the negative Gibbs free energy change of the Li-Al alloy formation reaction.

Efeito da adição de Na2O na viscosidade e devitrificação do vidro obtido a partir de cinzas volantes e Li2O Influence of Na2O on the viscosity and devitrification behavior of glasses obtained from fly ashes and Li2O

Directory of Open Access Journals (Sweden)

Etney Neves

1998-07-01

Full Text Available Glass-ceramic materials can be produced by the addition of LiO2 to fly ashes disposible in Southern Brazil. These glass-ceramics are based on the Al2O3-SiO2-Li 2O system. The high viscosity of the obtained glasses, however, makes forming useful articles with these materials difficult. In this study we investigate the effect of adding low cost Na2CO3 on the melt viscosity and on the nature of the developed crystalline phases. It was intended that the ultimate crystalline phase (LiAlSi3O8 should not be altered. With additions up to 3 wt. % Na2CO3, the viscosity was apparently lowered and no new crystalline phase were detected.

Evaluation of structure, dielectric and electrical properties of (Li/Ta/Sb modified (Na, K NbO3 lead-free ceramics with excess Na concentration

Directory of Open Access Journals (Sweden)

Md. Kashif Shamim

2017-12-01

Full Text Available Polycrystalline perovskite structured (Li0.04 (Na0.54+x K0.460.96 (Nb0.81Ta0.15 Sb0.04 O3 ceramics with x=0.00, 0.005 and 0.01 mole excess Na concentration were prepared by solid state sintering method. The present study relates the role of excess Na addition with the stoichiometry, density, structure, dielectric and ferroelectric properties of the samples. X-ray diffraction (XRD pattern exhibits single phase orthorhombic structure. The characteristic Raman modes were observed due to translational modes of cations and vibrational modes of NbO6 octahedra and no structural phase transition were observed. This confirms the formation of single phase perovskite structure and is consistent with XRD results. The dielectric permittivity increases about two times, while dielectric loss decreases by four times for x=0.01 composition. The electrical measurements carried by Complex Impedance spectroscopic analysis suggest negative temperature coefficient of resistance (NTCR behavior.

Textured and tungsten-bronze-niobate-doped (K,Na,Li)(Nb,Ta)O3 piezoceramic materials

International Nuclear Information System (INIS)

Soller, Thomas; Bathelt, Robert; Benkert, Katrin; Bodinger, Hermann; Schuh, Carsten; Schlenkrich, Falko

2010-01-01

In this study, the effects of an alkaline-earth niobate doping in tungsten-bronze (TB) stoichiometry on the piezoelectric properties and the phase transition temperatures of lead-free (K,Na,Li)(Nb,Ta)O 3 ceramics were investigated. In particular, the TB compounds barium niobate (BN), barium sodium niobate (BNN) and strontium calcium sodium niobate (SCNN) were investigated. The TB-modified ceramics show promising piezoelectric properties with large-signal piezo coefficients, d 33 * lose to 400 pm/V, planar coupling coefficients, k p , up to 0.45 and Curie temperatures of approximately 310 .deg. C. In addition, the effect of texturing on the undoped (K,Na,Li)(Nb,Ta)O 3 base composition via templated grain growth (TGG) with microcrystalline NaNbO 3 templates was examined. Lotgering factors up to 81% and strain enhancements by a factor 1.5 with large-signal values of d 33 * up to 550 pm/V could be achieved in the textured samples.

Functionalized NbS2 as cathode for Li- and Na-ion batteries

KAUST Repository

Zhu, Jiajie

2017-07-27

Cathodes of Li- and Na-ion batteries usually have capacities <200 mAh/g, significantly less than the anodes. Two-dimensional materials can overcome this limitation but suffer from low voltages. In this context, we investigate NbS2 functionalized by O, F, and Cl as a cathode material by first-principles calculations, considering both the conversion and intercalation mechanisms. NbS2O2 shows a higher voltage than NbS2 for both Li and Na, but the voltage decreases drastically for increasing ion coverage. Even higher voltages and favorable dependences on the ion coverage are achieved by F and Cl functionalization. We obtain NbS2F2 and NbS2Cl2 energy densities of 1223 mW h/g and 823 mW h/g for lithiation and 1086 mW h/g and 835 mW h/g for sodiation, respectively. These values are higher than those for most state-of-the-art cathode materials (∼600 mW h/g). In addition, low diffusion barriers enable high cycling rates.

Functionalized NbS2 as cathode for Li- and Na-ion batteries

KAUST Repository

Zhu, Jiajie; Alshareef, Husam N.; Schwingenschlö gl, Udo

2017-01-01

Cathodes of Li- and Na-ion batteries usually have capacities <200 mAh/g, significantly less than the anodes. Two-dimensional materials can overcome this limitation but suffer from low voltages. In this context, we investigate NbS2 functionalized by O, F, and Cl as a cathode material by first-principles calculations, considering both the conversion and intercalation mechanisms. NbS2O2 shows a higher voltage than NbS2 for both Li and Na, but the voltage decreases drastically for increasing ion coverage. Even higher voltages and favorable dependences on the ion coverage are achieved by F and Cl functionalization. We obtain NbS2F2 and NbS2Cl2 energy densities of 1223 mW h/g and 823 mW h/g for lithiation and 1086 mW h/g and 835 mW h/g for sodiation, respectively. These values are higher than those for most state-of-the-art cathode materials (∼600 mW h/g). In addition, low diffusion barriers enable high cycling rates.

Emission spectra of alkali-metal (K,Na,Li)-He exciplexes in cold helium gas

International Nuclear Information System (INIS)

Enomoto, K.; Hirano, K.; Kumakura, M.; Takahashi, Y.; Yabuzaki, T.

2004-01-01

We have observed emission spectra of excimers and exciplexes composed of a light alkali-metal atom in the first excited state and 4 He atoms [K*He n (n=1-6), Na * He n (n=1-4), and Li * He n (n=1,2)] in cryogenic He gas (the temperature 2 K -1 . Differently from exciplexes with heavier alkali-metal atoms, the spectra for the different number of He atoms were well separated, so that their assignment could be made experimentally. Comparing with the spectra of K * He n , we found that the infrared emission spectrum of the K atom excited in liquid He was from K*He 6 . To confirm the assignment, we have also carried out ab initio calculation of adiabatic potential curves and peak positions of the emission spectra of the exciplexes

6,7Li + 28Si total reaction cross sections at near barrier energies

International Nuclear Information System (INIS)

Pakou, A.; Musumarra, A.; Pierroutsakou, D.; Alamanos, N.; Assimakopoulos, P.A.; Divis, N.; Doukelis, G.; Gillibert, A.; Harissopulos, S.; Kalyva, G.; Kokkoris, M.; Lagoyannis, A.; Mertzimekis, T.J.; Nicolis, N.G.; Papachristodoulou, C.; Perdikakis, G.; Roubos, D.; Rusek, K.; Spyrou, S.; Zarkadas, Ch.

2007-01-01

Total reaction cross section measurements for the 6,7 Li + 28 Si systems have been performed at near-barrier energies. The results indicate that, with respect to the potential anomaly at barrier, 6 Li and 7 Li on light targets exhibit similar energy dependence on the imaginary potential. Comparisons are made with 6,7 Li cross sections on light and heavy targets, extracted via previous elastic scattering measurements and also with CDCC calculations. Energy dependent parametrisations are also obtained for total reaction cross sections of 6,7 Li on Si, as well as on any target, at near barrier energies

Structure factors and phonon dispersion in liquid Li0.61Na0.39 alloy

International Nuclear Information System (INIS)

Pratap, Arun; Lad, Kirit N.; Raval, K.G.

2004-01-01

The phonon spectra for liquid Li and Na have been computed through the phenomenological model of Bhatia and Singh for disordered systems like liquids and glasses and the obtained results have been compared with the available data obtained by inelastic neutron scattering (INS) and inelastic X-ray scattering (IXS) experiments. The effective pair potentials and their space derivatives are important ingredients in the computation of the dispersion curves. The pair potentials are obtained using the pseudo-potential theory. The empty core model proposed by Ashcroft is widely used for pseudo-potential calculations for alkali metals. But, it is thought to be unsuitable for Li because of its simple 1s electronic structure. However, it can be used with an additional term known as Born-Mayer (BM) core term. The influence of the BM core term on the phonon dispersion is discussed. The same pseudo-potential formalism has been employed to obtain the dispersion relation in liquid Li 0.61 Na 0.39 alloy. Apart from the phonon spectra, the Ashcroft-Langreth structure factors in the alloy are derived in the Percus-Yevick approximation. (author)

NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

NARCIS (Netherlands)

SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

1993-01-01

Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,

New thermally stable red-emitting phosphors Pr{sup 3+}, M{sup +}:SrB{sub 4}O{sub 7} (M=Li, Na, K)

Energy Technology Data Exchange (ETDEWEB)

Xiong, F.B., E-mail: fbxiong@xmut.edu.cn [Department of Optoelectronics, Xiamen University of Technology, Xiamen 361024 (China); Fujian Provincial Key Laboratory of Optoelectronic Information Materials and Devices, Xiamen University of Technology, Xiamen 361024 (China); Lin, H.F.; Xu, Y.C.; Shen, H.X. [Department of Optoelectronics, Xiamen University of Technology, Xiamen 361024 (China); Zhu, W.Z. [Department of Optoelectronics, Xiamen University of Technology, Xiamen 361024 (China); Fujian Provincial Key Laboratory of Optoelectronic Information Materials and Devices, Xiamen University of Technology, Xiamen 361024 (China)

2016-09-15

New red-emitting phosphors Pr{sup 3+}, M{sup +}:SrB{sub 4}O{sub 7} (M=Li, Na, K) in pure phase were synthesized via high-temperature solid-state reaction. Luminescent properties of those phosphors were characterized in detail. Pr{sup 3+}, M{sup +}:SrB{sub 4}O{sub 7} (M=Li, Na, K) can be excited under the range of 430–500 nm excitation, which covers the emission spectra of blue InGaN chip, exhibits pure red emission bands centered at 605 and 662 nm. The alkali-metal Li{sup +}, Na{sup +}, or K{sup +} acting as charge compensators can improve fluorescent emission intensities of Pr{sup 3+} ions, and Pr{sup 3+}, Na{sup +}:SrB{sub 4}O{sub 7} shows the strongest emission intensities among those phosphors. Concentration quenching could be attributed to electric dipole–dipole interaction among Pr{sup 3+} ions. The temperature-dependent luminescence indicated Pr{sup 3+}, Na{sup +}:SrB{sub 4}O{sub 7} shows highly thermal stability. Those work suggests that Pr{sup 3+}, M{sup +}:SrB{sub 4}O{sub 7} (M=Li, Na, K) as thermally stable red-emitting phosphor might be potentially applied in WLED.

THE 2H(alpha, gamma6LI REACTION AT LUNA AND BIG BANG NUCLEOSYNTHETIS

Directory of Open Access Journals (Sweden)

Carlo Gustavino

2013-12-01

Full Text Available The 2H(α, γ6Li reaction is the leading process for the production of 6Li in standard Big Bang Nucleosynthesis. Recent observations of lithium abundance in metal-poor halo stars suggest that there might be a 6Li plateau, similar to the well-known Spite plateau of 7Li. This calls for a re-investigation of the standard production channel for 6Li. As the 2H(α, γ6Li cross section drops steeply at low energy, it has never before been studied directly at Big Bang energies. For the first time the reaction has been studied directly at Big Bang energies at the LUNA accelerator. The preliminary data and their implications for Big Bang nucleosynthesis and the purported 6Li problem will be shown.

LiPF{sub 6}. Synthesis and stability in EC/DMC and PC/DMC mixtures; LiPF{sub 6}. Synthese et stabilite dans les melanges EC/DMC et PC/DMC

Energy Technology Data Exchange (ETDEWEB)

Naejus, R.; Coudert, R.; Lemordant, D. [Laboratoire P.I.M.I.R. EA, Sciences et Techniques, 37 - Tours (France); Willmann, P. [CNES, 31 - Toulouse (France)

1996-12-31

Lithium hexa-fluoro-phosphate LiPF{sub 6} is recommended for the replacement of the toxic LiAsF{sub 6} and the explosive perchlorates (like LiClO{sub 4}) in rechargeable lithium electrochemical generators. The aim of this work is to develop a new method of synthesis of this salt and to check its stability with respect to carbonated solvents: ethylene carbonate (EC), propylene carbonate (PC) and dimethyl-carbonate (DMC) in already optimized EC/DMC and PC/DMC binary mixtures. Two methods using HPF{sub 6} are proposed: the first one uses the direct neutralization of this commercial acid by LiOH in aqueous, alcoholic or acetonitrile environment, while in the second one LiPF{sub 6} is obtained from pyridinium hexa-fluoro-phosphate synthesized from HPF{sub 6} using a new and simple protocol. (J.S.) 24 refs.

LiPF{sub 6}. Synthesis and stability in EC/DMC and PC/DMC mixtures; LiPF{sub 6}. Synthese et stabilite dans les melanges EC/DMC et PC/DMC

Energy Technology Data Exchange (ETDEWEB)

Naejus, R; Coudert, R; Lemordant, D [Laboratoire P.I.M.I.R. EA, Sciences et Techniques, 37 - Tours (France); Willmann, P [CNES, 31 - Toulouse (France)

1997-12-31

Lithium hexa-fluoro-phosphate LiPF{sub 6} is recommended for the replacement of the toxic LiAsF{sub 6} and the explosive perchlorates (like LiClO{sub 4}) in rechargeable lithium electrochemical generators. The aim of this work is to develop a new method of synthesis of this salt and to check its stability with respect to carbonated solvents: ethylene carbonate (EC), propylene carbonate (PC) and dimethyl-carbonate (DMC) in already optimized EC/DMC and PC/DMC binary mixtures. Two methods using HPF{sub 6} are proposed: the first one uses the direct neutralization of this commercial acid by LiOH in aqueous, alcoholic or acetonitrile environment, while in the second one LiPF{sub 6} is obtained from pyridinium hexa-fluoro-phosphate synthesized from HPF{sub 6} using a new and simple protocol. (J.S.) 24 refs.

Synthesize and electrochemical characterization of Mg-doped Li-rich layered Li[Li0.2Ni0.2Mn0.6]O2 cathode material

International Nuclear Information System (INIS)

Wang, Dan; Huang, Yan; Huo, Zhenqing; Chen, Li

2013-01-01

Highlights: • Layered Li[Li 0.2 Ni 0.2−x Mn 0.6−x Mg 2x ]O 2 (2x = 0, 0.01, 0.02, 0.05) were synthetized. • Li[Li 0.2 Ni 0.2−x Mn 0.6−x Mg 2x ]O 2 exhibit enhanced electrochemical properties. • The improved performance is attributed to enhanced structure stability. -- Abstract: Mg-doped Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 as a Li-rich cathode material of lithium-ion batteries were prepared by co-precipitation method and ball-milling treatment using Mg(OH) 2 as a dopant. Scanning electron microscopy (SEM), ex situ X-ray powder diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvantatic charge/discharge were used to investigate the effect of Mg doping on structure and electrochemical performance. Compared with the bare material, Mg-doped materials exhibit better cycle stabilities and superior rate capabilities. Li[Li 0.2 Ni 0.195 Mn 0.595 Mg 0.01 ]O 2 displays a high reversible capacity of 226.5 mAh g −1 after 60 cycles at 0.1 C. The excellent cycle performance can be attributed to the improvement in structure stability, which is verified by XRD tests before and after 60 cycles. EIS results show that Mg doping decreases the charge-transfer resistance and enhances the reaction kinetics, which is considered to be the major factor for higher rate performance

Electromagnetic form factors and vertex constants for 6Li

International Nuclear Information System (INIS)

Blokhintsev, L.D.; Shvarts, I.A.

1977-01-01

It has been assumed that the main contribution to the rapidly changing part of the charge form factor of 6 Li provides the amplitude of the triangle diagram containing virtual lines of deuteron and α particle. The vertex constant G 2 for the 6 Li→α+d decay is expressed through the nuclear charge radii for 6 Li, d, and α. Taking into account coulomb interaction in the vertex of the 6 Li→α+d reaction increases G 2 by about a factor of two. The account of virtuality of a deuteron cluster also leads to an increase in G 2

Lithium Insertion in LiCr3O8, NaCr3O8, and KCr3O8 at Room Temperature and at 125°C

DEFF Research Database (Denmark)

Koksbang, R.; Fauteux, D.; Norby, P.

1989-01-01

Lithium insertion and deinsertion reactions have been carried out with LiCr3O8, NaCr3O8, and KCr3O8 chemically andelectrochemically at room temperature and at 125°C. The electrochemical experiments were performed with a nonaqueousliquid electrolyte at room temperature and with a polymer electroly...... is close to 4Li/NaCr3O8 and 1.3Li/KCr3O8.Lithium ion diffusion coefficients are similar for the two compounds in the comparable composition range.Thermally, the fully lithiated compounds appear to be as stable as the pristine materials.......Lithium insertion and deinsertion reactions have been carried out with LiCr3O8, NaCr3O8, and KCr3O8 chemically andelectrochemically at room temperature and at 125°C. The electrochemical experiments were performed with a nonaqueousliquid electrolyte at room temperature and with a polymer electrolyte....... At elevated temperatures, the isostructural compounds NaCr3O8 and KCr3O8 are able to accommodate morethan 4Li/MCr3O8. During this process, minor structural changes are observed. At room temperature, NaCr3O8 and KCr3O8also accommodate Li topotactically, but the maximum number of Li inserted per formula...

Porous-Nickel-Scaffolded Tin-Antimony Anodes with Enhanced Electrochemical Properties for Li/Na-Ion Batteries.

Science.gov (United States)

Li, Jiachen; Pu, Jun; Liu, Ziqiang; Wang, Jian; Wu, Wenlu; Zhang, Huigang; Ma, Haixia

2017-08-02

The energy and power densities of rechargeable batteries urgently need to be increased to meet the ever-increasing demands of consumer electronics and electric vehicles. Alloy anodes are among the most promising candidates for next-generation high-capacity battery materials. However, the high capacities of alloy anodes usually suffer from some serious difficulties related to the volume changes of active materials. Porous supports and nanostructured alloy materials have been explored to address these issues. However, these approaches seemingly increase the active material-based properties and actually decrease the electrode-based capacity because of the oversized pores and heavy mass of mechanical supports. In this study, we developed an ultralight porous nickel to scaffold with high-capacity SnSb alloy anodes. The porous-nickel-supported SnSb alloy demonstrates a high specific capacity and good cyclability for both Li-ion and Na-ion batteries. Its capacity retains 580 mA h g -1 at 2 A g -1 after 100 cycles in Li-ion batteries. For a Na-ion battery, the composite electrode can even deliver a capacity of 275 mA h g -1 at 1 A g -1 after 1000 cycles. This study demonstrates that combining the scaffolding function of ultralight porous nickel and the high capacity of the SnSb alloy can significantly enhance the electrochemical performances of Li/Na-ion batteries.

Magnetoplastic effect in irradiated NaCl and LiF crystals

International Nuclear Information System (INIS)

Al'shitz, V.I.; Darinskaya, E.V.; Kazakova, O.L.

1997-01-01

The effect of low x-ray irradiation doses (≅10 2 rad) on the magnetoplastic effect - the detachment of dislocations from paramagnetic centers under the action of an external magnetic field B - in alkali-halide crystals has been investigated. The measurements were performed on LiF crystals and three types of NaCl crystals, differing in impurity content. The dependence of the mean free path l of the dislocations on the rotational frequency ν of a sample in a magnetic field was especially sensitive to low irradiation doses. In unirradiated crystals this dependence is a single-step dependence and is characterized by a critical frequency ν c ∝B 2 above which the magnetoplastic effect is not observed. The frequency ν c depends only on the type of paramagnetic centers, and not on their density. Even the lowest irradiation dose employed ( c2 , that is insensitive to the irradiation dose, and that corresponds to the appearance of magnetically sensitive stoppers of a new type under irradiation. The initial critical frequency ν c1 , as a rule, also varies with the dose, reflecting the change in state of the impurity complexes (Ca in NaCl and Mg in LiF). Specifically, it is shown for NaCl(Ca) crystals that as the irradiation dose increases, the frequency ν c1 increases, gradually approaching the value ν c2 , so that by the time the dose is ≅300 rad, the dependence l(ν) once again becomes a single-step dependence, dropping sharply only for ν≥ν c2 . It is shown that the addition of a small number of Ni atoms to a NaCl crystal makes the Ca complexes radiation resistant, and the critical frequency ν c1 corresponding to them initially equals ν c2 for crystals with no Ni. The recombination kinetics of radiation defects in the case in which the samples are irradiated under a tungsten lamp was investigated. A possible physical model of the observed dependences is discussed

Li4FeH6: Iron-containing complex hydride with high gravimetric hydrogen density

Directory of Open Access Journals (Sweden)

Hiroyuki Saitoh

2014-07-01

Full Text Available Li4FeH6, which has the highest gravimetric hydrogen density of iron-containing complex hydrides reported so far, is synthesized by hydrogenation of a powder mixture of iron and LiH above 6.1 GPa at 900 °C. In situ synchrotron radiation X-ray diffraction measurements reveal that while kinetics require high temperature and thus high pressure for the synthesis, Li4FeH6 is expected to be thermodynamically stable slightly below room temperature at ambient pressure; further synthetic studies to suppress the kinetic effects may enable us to synthesize Li4FeH6 at moderate pressures. Li4FeH6 can be recovered at ambient conditions where Li4FeH6 is metastable.

Borophene as an anode material for Ca, Mg, Na or Li ion storage: A first-principle study

Science.gov (United States)

Mortazavi, Bohayra; Dianat, Arezoo; Rahaman, Obaidur; Cuniberti, Gianaurelio; Rabczuk, Timon

2016-10-01

Borophene, the boron atom analogue to graphene, being atomic thick have been just recently experimentally fabricated. In this work, we employ first-principles density functional theory calculations to investigate the interaction of Ca, Mg, Na or Li atoms with single-layer and free-standing borophene. We first identified the most stable binding sites and their corresponding binding energies as well and then we gradually increased the ions concentration. Our calculations predict strong binding energies of around 4.03 eV, 2.09 eV, 2.92 eV and 3.28 eV between the borophene substrate and Ca, Mg, Na or Li ions, respectively. We found that the binding energy generally decreases by increasing the ions content. Using the Bader charge analysis, we evaluate the charge transfer between the adatoms and the borophene sheet. Our investigation proposes the borophene as a 2D material with a remarkably high capacity of around 800 mA h/g, 1960 mA h/g, 1380 mA h/g and 1720 mA h/g for Ca, Mg, Na or Li ions storage, respectively. This study can be useful for the possible application of borophene for the rechargeable ion batteries.

Double molybdates in Li2MoO4 - Na2MoO4 - H2O system at 25 grad C

International Nuclear Information System (INIS)

Karov, Z.G.; Mirzoev, R.S.; Makitova, D.D.; Zhilova, S.B.; Podnek, A.G.; Urusova, R.Kh.

1989-01-01

Solubility in Li 2 MoO 4 - Na 2 MoO 4 - H 2 O system at 25 deg C is first stuied. Formation of two Li 2 MoO 4 · Na 2 MoO 4 · 4H 2 O and Li 2 MoO 4 · 3Na 2 MoO 4 · 12H 2 O compounds in a system is ascertained. Density, refractive index, viscosity, surface tension, electric conductivity and pH of saturated solutions are determined. Isothermes of mole volume, equivalent and reduced electric conductivity and seeming mole volume of salts sum in solutions are calculated. All these properties adequtely confirm the character of components interaction in a system determined by solubility method. Crystallhydrates of binary molybdates are separated, indentified and studied

Calculation of vibrational spectra of complex hydrides, LiBeH/sub 3/, NaBeH/sub 3/ and LiMgH/sub 3/

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, L P; Boldyrev, A I [AN SSSR, Chernogolovka. Inst. Novykh Khimicheskikh Problem

1984-03-01

The non-empirical Hartree-Fock-Ruthan method with a two-exponent Ros-Zigban basis has been used to calculate the coefficients of harmonic force field, frequency and intensity of normal vibrations of the LiBeH/sub 3/, NaBeH/sub 3/ and LiMgH/sub 3/ complex hydrides. Attribution of vibrational types is conducted. Isotope shifts for different isotope substitutions in the L(MH/sub 3/) are calculated. The effect of the nature of both the outer-spherical cation L/sup +/ and central atom M on the vibrational spectrum is discussed.

The phase transformation and crystallization kinetics of (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses

Energy Technology Data Exchange (ETDEWEB)

Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Li, Wang-Long [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Cheng, Chih-Wei [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Chang, Kuo-Ming; Chen, Yong-Feng [Department of Electrical Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.tw [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China)

2010-09-01

The phase transformation and crystallization kinetics of (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na{sub 2}O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na{sub 2}O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 {+-} 22.2 to 284.0 {+-} 10.8 kJ mol{sup -1} when the Na{sub 2}O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 {+-} 10.8 to 446.0 {+-} 23.2 kJ mol{sup -1} when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses.

The tin-rich copper lithium stannides: Li{sub 3}Cu{sub 6}Sn{sub 4} and Li{sub 2}CuSn{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Fuertauer, Siegfried; Flandorfer, Hans [Vienna Univ. (Austria). Inst. of Inorganic Chemistry (Materials Chemisrty); Effenberger, Herta S. [Vienna Univ. (Austria). Inst. of Mineralogy and Crystallography

2015-05-01

The Sn rich ternary intermetallic compounds Li{sub 3}Cu{sub 6}Sn{sub 4} (CSD-427097) and Li{sub 2}CuSn{sub 2} (CSD-427098) were synthesized from the pure elements by induction melting and annealing at 400 C. Structural investigations were performed by powder- and single-crystal XRD. Li{sub 3}Cu{sub 6}Sn{sub 4} crystallizes in space group P6/mmm; it is structurally related to but not isotypic with MgFe{sub 6}Ge{sub 6} (a = 5.095(2) Aa, c = 9.524(3) Aa; wR{sub 2} = 0.059; 239 unique F{sup 2}-values, 17 free variables). Li{sub 3}Cu{sub 6}Sn{sub 4} is characterized by two sites with a mixed Cu:Sn occupation. In contrast to all other Cu-Li-Sn compounds known so far, any mixed occupation was found for Cu-Li pairs only. In addition, one Li site is only half occupied. The second Sn rich phase is Li{sub 2}CuSn{sub 2} (space group I4{sub 1}/amd, a = 4.4281(15) Aa, c = 19.416(4) Aa; wR{sub 2} = 0.033; 213 unique F{sup 2}-values, 12 atom free variables); it is the only phase in the Cu-Li-Sn system which is noted for full ordering. Both crystal structures exhibit 3D-networks which host Li atoms in channels. They are important for understanding the lithiation mechanism in Cu-Sn electrodes for Li-ion batteries.

Computer modelling of defect structure and rare earth doping in LiCaAlF sub 6 and LiSrAlF sub 6

CERN Document Server

Amaral, J B; Valerio, M E G; Jackson, R A

2003-01-01

This paper describes a computational study of the mixed metal fluorides LiCaAlF sub 6 and LiSrAlF sub 6 , which have potential technological applications when doped with a range of elements, especially those from the rare earth series. Potentials are derived to represent the structure and properties of the undoped materials, then defect properties are calculated, and finally solution energies for rare earth elements are calculated, enabling preferred dopant sites and charge compensation mechanisms to be predicted.

Synthesis and structure of Na-Li-Si-Al-P-O-N glasses prepared by melt nitridation using NH3

International Nuclear Information System (INIS)

Kidar, A.; Pomeroy, M.J.; Hampshire, S.; Mercier, C.; Leriche, A.; Revel, B.

2012-01-01

Na-Li-Si-Al-P-O-N glasses have been prepared by nitridation of a pre-synthesized Na 2 O-Li 2 O-SiO 2 -P 2 O 5 -Al 2 O 3 glass under anhydrous ammonia. Nitrogen for oxygen substitution increases the network connectivity leading to increases in microhardness and glass transition temperature. Raman and 31 P MAS-NMR spectroscopy indicate sequential nitridation reactions forming PO 3 N and PO 2 N 2 species. The data collected so far show no evidence of N/O substitutions in the silicate sub-network. (authors)

X particle effect for 6Li reaction rates calculations

International Nuclear Information System (INIS)

Kocak, G.; Balantekin, A. B.

2009-01-01

The inferred primordial 6 L i-7 L i abundances are different from standard big bang nucleosynthesis results, 6 L i is 1000 times larger and 7 L i is 3 times smaller than the big bang prediction. In big bang nucleosynthesis, negatively charged massive X particles a possible solution to explain this primordial Li abundances problem [1]. In this study, we consider only X particle effect for nuclear reactions to obtain S-factor and reaction rates for Li. All S-factors calculated within the Optical Model framework for d(α,γ)6 L i system. We showed that the enhancement effect of massive negatively charged X particle for 6 L i system reaction rate.(author)

Big-Bang Nucleosynthesis with Negatively-Charged Massive Particles as a Cosmological Solution to the 6Li and 7Li Problems

International Nuclear Information System (INIS)

Kusakabe, Motohiko; Kajino, Toshitaka; Boyd, Richard N.; Yoshida, Takashi; Mathews, Grant J.

2008-01-01

Observations of metal poor halo stars exhibit a possible plateau of 6 Li abundance as a function of metallicity similar to that for 7 Li, suggesting a big bang origin. However, the inferred primordial abundance of 6 Li is ∼1000 times larger than that predicted by standard big bang nucleosynthesis (BBN) for the baryon-to-photon ratio inferred from the WMAP data. On the other hand, the inferred 7 Li primordial abundance is about 3 times smaller than the prediction. We study a possible simultaneous solution to both the problems of underproduction of 6 Li and overproduction of 7 Li in BBN. This solution involves a hypothetical massive, negatively-charged leptonic particle that would bind to the light nuclei produced in BBN, but would decay long before it could be detected. Because the particle gets bound to the existing nuclei after the cessation of the usual big bang nuclear reactions, a second longer epoch of nucleosynthesis can occur among X-nuclei which have reduced Coulomb barriers. We numerically carry out a fully dynamical BBN calculation, simultaneously solving the recombination and ionization processes of negatively-charged particles by normal and X-nuclei as well as many possible nuclear reactions among them. We confirm that a reaction in which the hypothetical particle is transferred can occur that greatly enhance the production of 6 Li while a reaction through an atomic excited state of X-nucleus depletes 7 Li. It is confirmed that BBN in the presence of these hypothetical particles, together with or without an event of stellar burning process, can simultaneously solve the two Li abundance problems

Ionic ASi{sub 2}N{sub 3} (A=Li, Na, K and Rb) stabilized by the covalent Si–N bonding: First-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Zhang, Huijun [College of Information Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Ren, Jiadong, E-mail: jdren@ysu.edu.cn [College of Information Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Wu, Lailei [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Zhang, Jingwu, E-mail: zjw@ysu.edu.cn [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

2017-01-15

The structural, elastic and electronic properties of LiSi{sub 2}N{sub 3} and its substitutions by Na, K and Rb were investigated through first-principles computations. The expansion of lattice parameters of ASi{sub 2}N{sub 3} from Li, Na, K to Rb is found to be determined by the bond angle of Si–N1–Si, which suggests a possible way to improve the lithium ionic conductivity by substitutions. ASi{sub 2}N{sub 3} (A=Li, Na, K and Rb) shows the similar elastic behaviors, while the electronic band gap gradually decreases from 5.1 to 3.4 eV from LiSi{sub 2}N{sub 3} to RbSi{sub 2}N{sub 3}. Interestingly, the analysis of electronic structure, crystal orbital Hamiltonian populations and Bader charges shows that the covalence of Si–N bonding is critical for the stability of ASi{sub 2}N{sub 3} phase. Among ASi{sub 2}N{sub 3} phases, there is a relatively high ionicity in NaSi{sub 2}N{sub 3}; the Si–N bond strength in [Si{sub 2}N{sub 3}]{sup −} net for KSi{sub 2}N{sub 3} and RbSi{sub 2}N{sub 3} is comparable to LiSi{sub 2}N{sub 3}, but stronger than NaSi{sub 2}N{sub 3}. - Graphic abstract: Universal trend of structural and electronic properties in alkaline metal silicon nitrides, ASi{sub 2}N{sub 3}, A=Li, Na, K and Rb. - Highlights: • Trend in structure, electronic and mechanical properties of ASi{sub 2}N{sub 3} (A=Li-Rb) were predicted. • Lattice expansion of ASi{sub 2}N{sub 3} induced by the bond angle of Si–N1–Si was found. • Calculated band gap decreases from 5.1 to 3.4 eV from LiSi{sub 2}N{sub 3} to RbSi{sub 2}N{sub 3}. • Covalent Si–N bonding is critical for the stability of ASi{sub 2}N{sub 3}.

VUV spectroscopy of pure LiCaAlF6 crystals

International Nuclear Information System (INIS)

Kirm, M.; True, M.; Vielhauer, S.; Zimmerer, G.; Shiran, N.V.; Shpinkov, I.; Spassky, D.; Shimamura, K.; Ichinose, N.

2005-01-01

Reflection, excitation and luminescence spectra of as-grown and X-ray irradiated high-purity LiCaAlF 6 crystals were studied in the temperature range of 10-300 K using synchrotron radiation in VUV. The intrinsic luminescence of samples at 10 K consists of a non-elementary broad band with maximum at 4.4 eV under excitation at 11.45 eV. It is ascribed to the radiative decay of self-trapped excitons. The energy gap is estimated to be 12.65 eV in LiCaAlF 6 . Under interband excitation a red shift of luminescence was observed. The electron-hole recombination leads to the emission peaking at 3.7 eV. The excitation processes and origin of overlapping emissions of LiCaAlF 6 are discussed

A comparative structural and electrochemical study of monoclinic Li3V2(PO4)3/C and rhombohedral Li2.5Na0.5V(2−2x/3)Nix(PO4)3/C

International Nuclear Information System (INIS)

Wang, Wenhui; Chen, Zhenyu; Zhang, Jiaolong; Dai, Changsong; Li, Jiajie; Ji, Dalong

2013-01-01

In order to synthesize pure derivative of rhombohedral Li 3 V 2 (PO 4 ) 3 (LVP), lithium-ion batteries materials Li 2.5 Na 0.5 V (2−2x/3) Ni x (PO 4 ) 3 /C (x = 0.03, 0.06, 0.09) and its control, monoclinic Li 3 V 2 (PO 4 ) 3 /C (LVP/C), were prepared by sol–gel method. The samples were investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), Raman spectroscopy, and electrochemical methods. The XRD patterns of Li 2.5 Na 0.5 V (2−2x/3) Ni x (PO 4 ) 3 /C are in good agreement with that of rhombohedral LVP, which indicates that the Na + –Ni 2+ composite doping can change the structure of monoclinic LVP. All the composite doping samples displayed a single flat plateau at 3.7 V in the charge/discharge voltage profile, which is caused by transformation of multi-phase mechanism to single-phase mechanism. For Li 2.5 Na 0.5 V 1.98 Ni 0.03 (PO 4 ) 3 /C, a specific discharge capacity of 108 mAh g −1 was achieved at a 0.5 C charge rate and a 1 C discharge rate, and a 99.0% retention rate of the initial capacity was obtained after 50 cycles

Nematic fluctuations in iron arsenides NaFeAs and LiFeAs probed by 75As NMR

Science.gov (United States)

Toyoda, Masayuki; Kobayashi, Yoshiaki; Itoh, Masayuki

2018-03-01

75As NMR measurements have been made on single crystals to study the nematic state in the iron arsenides NaFeAs, which undergoes a structural transition from a high-temperature (high-T ) tetragonal phase to a low-T orthorhombic phase at Ts=57 K and an antiferromagnetic transition at TN=42 K, and LiFeAs having a superconducting transition at Tc=18 K. We observe the in-plane anisotropy of the electric field gradient η even in the tetragonal phase of NaFeAs and LiFeAs, showing the local breaking of tetragonal C4 symmetry. Then, η is found to obey the Curie-Weiss (CW) law as well as in Ba (Fe1-xCox) 2As2 . The good agreement between η and the nematic susceptibility obtained by electronic Raman spectroscopy indicates that η is governed by the nematic susceptibility. From comparing η in NaFeAs and LiFeAs with η in Ba (Fe1-xCox) 2As2 , we discuss the carrier-doping dependence of the nematic susceptibility. The spin contribution to nematic susceptibility is also discussed from comparing the CW terms in η with the nuclear spin-lattice relaxation rate divided by temperature 1 /T1T . Finally, we discuss the nematic transition in the paramagnetic orthorhombic phase of NaFeAs from the in-plane anisotropy of 1 /T1T .

Accumulation of Cs, Sr into leaves and grain of winter wheat under act of N, Zn, Li, Na

International Nuclear Information System (INIS)

Grodzinsky, D.; Tkatchuk, K.; Zhmurko, N.; Bogdan, T.; Guralchuk, Zh.

1998-01-01

The experiments were carried out on cv Lutencens 7 winter wheat grown on grey forest soil. In order to study the influence of nitrogen on Cs and Sr accumulation, a background of P60 K60 added in autumn different doses of nitrogen (30, 60, 120 kg/ha) were applied in spring. The influence of micronutrients on Cs and Sr accumulation was studied by adding 3 kg/ha Zn and 2 kg/ha Li to the soil under ploughing on background of N60 P60 K60. Besides the foliar application with 0.05% Na 2 SO 4 was carried out. Cation content (Cs, Sn, Zn, Li, Na) in soil and plant organs was determined by atomic absorption spectrophotometry. The Cs, Sr content in control plant leaves made up 15.0 and 21.0 mg per g of dry matter at the early stages of plant development. As the plants aged, the content of those elements in the leaves decreased strongly (3-4 times). At early stages of plant development, nitrogen caused an 8.9-11% increase in the Cs content of the leaves. At the stages of heading to grain filling, the Cs content increase was only observed at a high nitrogen dose, whereas low nitrogen doses had no effected on Cs accumulation in leaves. In should be noted that nitrogen (N60 and N120) decreased the Cs content in grain by 32-33%. As for the Sr content of grain, this was 3 to 4-fold less than that of Cs. Nitrogen had no effected on the Sr content of grain. Zn and Li addition to soil as well as foliar nutrition with Na had a different effect on the Cs and Sr content of winter wheat leaves and grain. Addition of Li decreased the Cs and Sr content of old leaves by 13% and 25% respectively. Addition of Zn and Na decreased the Sr content of old leaves but had no effect on the Cs content. Zn, Na and Li reduced the Sr content in grain also, viz. by 16,11 and 7% respectively. Thus the research has demonstrated the possibility of regulating Cs and Sr accumulation in the above-ground organs of winter wheat plants

Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions

International Nuclear Information System (INIS)

Poel, M van der; Nielsen, C V; Rybaltover, M; Nielsen, S E; Machholm, M; Andersen, N

2002-01-01

We measure angle differential cross sections (DCS) in Li + + Na → Li + Na + electron transfer collisions in the 2.7-24 keV energy range. We do this with a newly constructed apparatus which combines the experimental technique of cold target recoil ion momentum spectroscopy with a laser-cooled target. This setup yields a momentum resolution of 0.12 au, an order of magnitude better angular resolution than previous measurements on this system. This enables us to clearly resolve Fraunhofer-type diffraction patterns in the angle DCS. In particular, the angular width of the ring structure is given by the ratio of the de Broglie wavelength λ dB = 150 fm at a velocity v = 0.20 au and the effective atomic diameter for electron capture 2R = 20 au. Parallel AO and MO semiclassical coupled-channel calculations of the Na(3s, 3p) → Li(2s, 2p) state-to-state collision amplitudes have been performed, and quantum scattering amplitudes are derived by the eikonal method. The resulting angle-differential electron transfer cross sections and their diffraction patterns agree with the experimental level-to-level results over most scattering angles in the energy range

Bare astrophysical S(E)-factor for the 6Li(d, α)4He and 7Li(p, α)4He reactions at astrophysical energies

International Nuclear Information System (INIS)

Pizzone, R.G.; Spitaleri, C.; Lattuada, M.; Musumarra, A.; Pellegriti, M.G.; Romano, S.; Tumino, A.; Cherubini, S.; Figuera, P.; Miljanic, D.; Rolfs, C.; Typel, S.; Wolter, H.H.; Castellani, V.; Degl'Innocenti, S.; Imperio, A.

2003-01-01

The Trojan Horse Method has been applied to study the 7 Li(p, α) 4 He and 6 (Li(d, α) 4 He reactions through the 7 Li(d, αα)n and 6 Li( 6 Li, αα) 4 He three body processes, respectively. The electron screening potential deduced from these experiments is much larger than the adiabatic approximation prediction for both cases; the systematic discrepancy between data and theoretical predictions is thus confirmed. Astrophysical implications of these measurements are also discussed

Dosimeter properties of Ce and Eu doped LiCaAlF6

International Nuclear Information System (INIS)

Yanagida, Takayuki; Fujimoto, Yutaka; Watanabe, Kenichi; Fukuda, Kentaro

2014-01-01

Optical, scintillation properties, optical stimulated luminescence, and thermally stimulated luminescence of Ce 1, 3, and 5% doped and Eu 1, 1.5, and 2% doped LiCaAlF 6 crystals fabricated by Tokuyama Corp. were investigated. In transmittance, absorption was proportional to dopant concentrations and typical optical quantum yield of Ce and Eu-doped LiCaAlF 6 were 40 and 100%, respectively. Scintillation wavelength and decay time profiles were investigated under X-ray irradiation. Ce 3+ and Eu 2+ 5d-4f luminescence appeared around 300 nm and 370 nm with typical decay time of 40 ns and 1.5 μs, respectively. Optically stimulated luminescence of Ce-doped ones appeared under 405 nm stimulation with detectable intensity while those of Eu doped ones were quite weak. Thermally stimulated luminescence of Ce- and Eu-doped LiCaAlF 6 were enough strong and they exhibited good response function from 1 to 1000 mGy exposure. - Highlights: • Optical, scintillation, OSL, and TSL properties of Ce or Eu differently doped LiCaAlF6 were studied. • PL quantum yield of Ce and Eu doped LiCaAlF6 showed 40% and 100%, respectively. • OSL was observed in Ce-doped LiCaAlF6. • TSL was observed in both material systems and exhibited a good dose response from 1 to 1000 mGy

Na7 [Fe2S6 ] , Na2 [FeS2 ] and Na2 [FeSe2 ] : New 'reduced' sodium chalcogenido ferrates

Science.gov (United States)

Stüble, Pirmin; Peschke, Simon; Johrendt, Dirk; Röhr, Caroline

2018-02-01

Three new 'reduced' FeII containing sodium chalcogenido ferrates were obtained applying a reductive synthetic route. The mixed-valent sulfido ferrate Na7 [Fe2S6 ] , which forms bar-shaped crystals with metallic greenish luster, was synthesized in pure phase from natural pyrite and elemental sodium at a maximum temperature of 800 °C. Its centrosymmetric triclinic structure (SG P 1 bar , a = 764.15(2), b = 1153.70(2), c = 1272.58(3) pm, α = 62.3325 (7) , β = 72.8345 (8) , γ = 84.6394 (8) ° , Z = 3, R1 = 0.0185) exhibits two crystallographically different [Fe2S6 ] 7 - dimers of edge-sharing [FeS4 ] tetrahedra, with somewhat larger Fe-S distances than in the fully oxidized FeIII dimers of e.g. Na6 [Fe2III S6 ] . In contrast to the localized AFM ordered pure di-ferrates(III), the Curie-Weiss behavior of the magnetic susceptibility proves the rarely observed valence-delocalized S = 9/2 state of the mixed-valent FeIII /FeII dimer. The nearly spin-only value of the magnetic moment combined with the chemical bonding not generally differing from that in pure ferrates(II) and (III), provides a striking argument, that the reduction of the local Fe spin moments observed in all condensed sulfido ferrate moieties is connected with the AFM spin ordering. The two isotypic ferrates(II) Na2 [FeS2 ] and Na2 [FeSe2 ] with chain-like structural units (SG Ibam, a = 643.54(8)/ 660.81(1), b = 1140.2(2)/1190.30(2) c = 562.90(6)/585.59(1) pm, Z = 4, R1 = 0.0372/0.0466) crystallize in the K2 [ZnO2 ] -type structure. Although representing merely further members of the common series of chalcogenido metallates(II) Na2 [MIIQ2 ] , these two new phases, together with Na6 [FeS4 ] and Li2 [FeS2 ] , are the only examples of pure FeII alkali chalcogenido ferrates. The new compounds allow for a general comparison of di- and chain ferrates(II) and (III) and mixed-valent analogs concerning the electronic and magnetic properties (including Heisenberg super-exchange and double-exchange interactions

Enhanced Lithium Ion Transport by Superionic Pathways Formed on the Surface of Two-dimensional Structured Li0.85Na0.15V3O8 for High-Performance Lithium Ion Batteries

International Nuclear Information System (INIS)

Lu, Xuena; Shang, Yu; Zhang, Sen; Deng, Chao

2015-01-01

Highlights: • Li 0.85 Na 0.15 V 3 O 8 nanosheet with superionic conductive layer was constructed. • Li x V 2 O 5 surface layer provides facile pathways for lithium migration. • Li x V 2 O 5 -Li 0.85 Na 0.15 V 3 O 8 composite displays good high rate capability. - Abstract: Poor ion transport and rate capability are the main challenges for LiV 3 O 8 as cathode material for lithium ion batteries. Here we report a novel strategy for enhancing lithium ion transport by building superionic pathways on the surface of Li 0.85 Na 0.15 V 3 O 8 nanosheet. The two-dimensional Li 0.85 Na 0.15 V 3 O 8 nanoparticle with an ion conductive layer of Li x V 2 O 5 on its surface is constructed by a modified sol–gel strategy with carefully controlled sodium incorporation and elements stoichiometry. Ultrathin Li x V 2 O 5 surface layer not only provides facile pathways for lithium migration, but also increases the structure stability during cycling. The Li x V 2 O 5 -Li 0.85 Na 0.15 V 3 O 8 composite displays good high rate capability of 172.3 mAh g −1 at 5C and excellent cycling stability of 98.9% over fifty cycles. This superior electrochemical property is attributed to the occupation of lithium site by Na + in LiV 3 O 8 host crystals and the surface superionic pathways of Li x V 2 O 5 phase. Therefore, the advantages of both high ion transport and the structure stabilization in present study put forward a new strategy for achieving high-performance LiV 3 O 8 electrode material with tailored nanoarchitecture

Quantification of Honeycomb Number-Type Stacking Faults: Application to Na3Ni2BiO6 Cathodes for Na-Ion Batteries.

Science.gov (United States)

Liu, Jue; Yin, Liang; Wu, Lijun; Bai, Jianming; Bak, Seong-Min; Yu, Xiqian; Zhu, Yimei; Yang, Xiao-Qing; Khalifah, Peter G

2016-09-06

Ordered and disordered samples of honeycomb-lattice Na3Ni2BiO6 were investigated as cathodes for Na-ion batteries, and it was determined that the ordered sample exhibits better electrochemical performance, with a specific capacity of 104 mA h/g delivered at plateaus of 3.5 and 3.2 V (vs Na(+)/Na) with minimal capacity fade during extended cycling. Advanced imaging and diffraction investigations showed that the primary difference between the ordered and disordered samples is the amount of number-type stacking faults associated with the three possible centering choices for each honeycomb layer. A labeling scheme for assigning the number position of honeycomb layers is described, and it is shown that the translational shift vectors between layers provide the simplest method for classifying different repeat patterns. It is demonstrated that the number position of honeycomb layers can be directly determined in high-angle annular dark-field scanning transmission electron microscopy (STEM-HAADF) imaging studies. By the use of fault models derived from STEM studies, it is shown that both the sharp, symmetric subcell peaks and the broad, asymmetric superstructure peaks in powder diffraction patterns can be quantitatively modeled. About 20% of the layers in the ordered monoclinic sample are faulted in a nonrandom manner, while the disordered sample stacking is not fully random but instead contains about 4% monoclinic order. Furthermore, it is shown that the ordered sample has a series of higher-order superstructure peaks associated with 6-, 9-, 12-, and 15-layer periods whose existence is transiently driven by the presence of long-range strain that is an inherent consequence of the synthesis mechanism revealed through the present diffraction and imaging studies. This strain is closely associated with a monoclinic shear that can be directly calculated from cell lattice parameters and is strongly correlated with the degree of ordering in the samples. The present results are

LiFSI vs. LiPF6 electrolytes in contact with lithiated graphite: Comparing thermal stabilities and identification of specific SEI-reinforcing additives

International Nuclear Information System (INIS)

Eshetu, Gebrekidan Gebresilassie; Grugeon, Sylvie; Gachot, Grégory; Mathiron, David; Armand, Michel; Laruelle, Stephane

2013-01-01

Lithium bis(fluorosulfonyl) imide (LiFSI) is regarded as an alternative to the classical LiPF 6 salt in today's LiFePO 4 /graphite-based Li-ion batteries electrolyte owing to its slightly higher conductivity and lower fluorine content. In an attempt to better evaluate the safety issues, here we report the comparative study of the LiFSI and LiPF 6 based electrolyte/lithiated graphite interface thermal behavior. DSC measurements with LiFSI-based electrolyte reveal a sharp exotherm with large heat release though at higher onset and peak temperatures compared to LiPF 6 -based electrolyte. With the help of GC/MS, 19 F NMR and ESI-HRMS analyses, we assume that this highly energetic peak around 200 °C, which is dependant upon the lithium content, is mainly related to electrochemical reduction of FSI − anion. In a strategy to limit the probability and damage of thermal runaway event, electrolyte additives such as vinylene carbonate (VC), fluoro ethylene carbonate (FEC), di-isocyanato hexane (DIH) and toluene di-isocyanate (TDI) have been investigated and shown to significantly lower the energy associated with the exothermic phenomenon

Development of antireflection coatings with a sup 6 LiF/ sup 6 sup 2 Ni multilayer converter for ultracold neutron detectors

CERN Document Server

Maier-Komor, P; Bergmaier, A; Dollinger, G; Paul, S; Schott, W

2002-01-01

High efficiency detectors for ultracold neutrons (UCN) are needed at the new high flux neutron source, Forschungsreaktor Muenchen II. In the development described, silicon PIN diodes were chosen to detect the alpha-particles or the tritons created in the reaction sup 6 Li(n,alpha)t. The high reflectance of UCN on sup 6 Li with its positive optical potential must be compensated by a material with negative optical potential. The isotope sup 6 sup 2 Ni was chosen for this. To avoid problems due to chemical reactions of Li with humidity, the compound sup 6 LiF was chosen. One hundred and fifty double layers of sup 6 LiF/ sup 6 sup 2 Ni had to be deposited by physical vapor deposition on silicon PIN diodes which had already been coated with 88 nm approx 77 mu g/cm sup 2 of sup 5 sup 8 Ni for reflection of the UCN. The theoretical optimal thickness of the sup 6 sup 2 Ni layers is 3 nm, and that of sup 6 LiF is 6 nm. Since expensive isotopes were involved, a small source-to-substrate distance had to be used, but wit...

Plasmon response in K, Na and Li clusters: systematics using the separable random-phase approximation with pseudo-Hamiltonians

International Nuclear Information System (INIS)

Kleinig, W.; Nesterenko, V.O.; Reinhard, P.-G.; Serra, Ll.

1998-01-01

The systematics of the plasmon response in spherical K, Na and Li clusters in a wide size region (8≤N≤440) is studied. We have considered two simplifying approximations whose validity has been established previously. First, a separable approach to the random-phase approximation is used. This involves an expansion of the residual interaction into a sum of separable terms until convergence is reached. Second, the electron-ion interaction is modelled by using the pseudo-Hamiltonian jellium model (MHJM) which includes nonlocal effects by means of realistic atomic pseudo-Hamiltonians. In cases where nonlocal effects are negligible the Structure Averaged Jellium Model (SAJM) has been used. Good agreement with available experimental data is achieved for K, Na (using the SAJM) and small Li clusters (invoking the PHJM). The trends for peak position and width are generally well reproduced, even up to details of the Landau fragmentation in several clusters. Less good agreement, however, is found for large Li clusters. This remains an open question

High-precision calculation of loosely bound states of LiPs+ and NaPs+

International Nuclear Information System (INIS)

Yamashita, Takuma; Kino, Yasushi

2015-01-01

A positronic alkali atom would be the first step to investigate behavior of a positronium(Ps) in an external field from atoms/molecules because the system can be regarded as a simple three-body system using model potentials reflecting electron orbitals of the ion core. In order to precisely determine binding energies and structures of positronic alkali atoms (LiPs + and NaPs + ), we improve the model potential so as to reproduce highly excited atomic energy levels of alkali atoms (Li and Na). The polarization potential included by the model potential is expanded in terms of Gaussian functions to finely determine a short range part of the potential which has been assumed to be a simple form. We find better reproducibility not only of atomic levels of the alkali atoms but also of the dipole polarizability of the core ion than previous works. We construct a model potential between a positron and an ion core based on the model potential between the valence electron and ion core. Binding energies associated with a dissociation of the alkali ion core and positronium, and interparticle distances are recalculated. Our results show slightly deeper bound than other previous studies. (paper)

Diffusion phenomena of fluorine and cations in molten Li2BeF4, LiBeF3 and NaBeF3

International Nuclear Information System (INIS)

Ohno, Hideo

1984-03-01

Self-diffusion coefficients of fluorine and cations in molten LiF-BeF 2 and NaF-BeF 2 systems were summarized by the capillary reservoir technique. The diffusion coefficients and the activation energies of cations in these molten salts follow a similar behavior with those of cations in molten alkali halides. On the other hand, self-diffusion of fluorine have unusually high diffusion coefficients and activation energies. The characteristic diffusion phenomena of fluorine in these molten alkali fluoroberyllates are very similar to those of oxygen in molten CaO-SiO 2 and CaO-SiO 2 -Al 2 O 3 slag. The dynamical behavior of Li and F in molten Li 2 BeF 4 was also analyzed by NMR technique. According to both these experiments, most probable mechanism of characteristic diffusion of fluorine in these molten systems could be dissociation of F atom from complex anion and long distance diffusion. (author)

Investigation of the antiprotonic X-ray spectra of the isotopes 6Li, 7Li and 40Ca

International Nuclear Information System (INIS)

Barth, H.

1987-04-01

With the commissioning of the Low-Energy Antiproton Ring (LEAR) at CERN in Geneva a high intensity, high purity antiproton beam became available, enabling precision measurements of antiprotonic X-ray spectra to be carried out. Besides informations about properties of the elementary particle antiproton itself, as for example its mass and its magnetic moment, such measurements provide informations about the strong-interaction potential between antiproton and nucleus at very low energies, which, in turn, can be derived from the elementary antinucleon-nucleon interaction by using microscopic models. This work investigates the antiprotonic X-ray spectra of the isotopes 6 Li, 7 Li and 40 Ca. The data were taken during the experiment PS176 at LEAR. The strong interaction between antiproton and nucleus leads to an energy shift ε and an absorption width Γ of the lower level of the last observable transition and also to intensity reductions, which can be converted to an absorption width for the upper level. For the isotopes 6 Li, 7 Li and 40 Ca the following results were obtained: 6 Li: ε(2p)=(-215±25) eV, Γ(2p)=(660±170) eV and Γ(3d)=(135±16) meV, 7 Li ε(2p)=(-265±20) eV, Γ(2p)=(690±170) eV and Γ(3d)=(129±13) meV, 40 Ca: ε(4f)=(-1060±130) eV, Γ(4f)=(3670±600) eV and Γ(5g)=(34.9±3.3) eV. The results are in fair agreement with theoretical calculations, at the same time showing up the limits of present understanding of antiproton-nucleus interaction. Particularly the spin-orbit part of the strong interaction seems to play a nonnegligible role. (orig.) [de

Basic technology for {sup 6}Li enrichment using an ionic-liquid impregnated organic membrane

Energy Technology Data Exchange (ETDEWEB)

Hoshino, Tsuyoshi, E-mail: hoshino.tsuyoshi@jaea.go.jp [Blanket Irradiation and Analysis Group, Fusion Research and Development Directorate, Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Higashi Ibaraki-gun, Ibaraki 311-1393 (Japan); Terai, Takayuki [The Institute of Engineering Innovation and Department of Nuclear Engineering and Management School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan)

2011-10-01

The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ({sup 6}Li) in tritium breeding materials. However, natural Li contains only about 7.6 at.% {sup 6}Li. In this paper, a new lithium isotope separation technique using an ionic-liquid impregnated organic membrane is proposed. In order to separate and concentrate lithium isotopes, only lithium ions are able to move through the membrane by electrodialysis between the cathode and the anode in lithium solutions. Preliminary experiments of lithium isotope separation were conducted using this phenomenon. Organic membranes impregnated with TMPA-TFSI and PP13-TFSI as ionic liquids were prepared, and the relationship between the {sup 6}Li separation coefficient and the applied electrodialytic conditions was evaluated using them. The results showed that the {sup 6}Li isotope separation coefficient in this method (about 1.1-1.4) was larger than that in the mercury amalgam method (about 1.06).

Thermal stability of LiNaR2F8 compounds (R=Ho-Lu, Y)

International Nuclear Information System (INIS)

Fedorov, P.P.; Medvedeva, L.V.; Bondareva, O.S.; Sobolev, B.P.

1990-01-01

Monoclinic pseudorhombic compound mentioned in the title are investigated. It is determined, that the compounds are stable within temperature narrow range: Ho - 575-693 degC, Er - 566-712deg C, Tm - 560-710 deg C, Yb - less than 685 deg C, Y - 580-712 deg C. Triangulation of LiF-NaF-YF 3 system is carried out

{sup 6}LiF oleic acid capped nanoparticles entrapment in siloxanes for thermal neutron detection

Energy Technology Data Exchange (ETDEWEB)

Carturan, S., E-mail: sara.carturan@lnl.infn.it; Maggioni, G., E-mail: Gianluigi.maggioni@lnl.infn.it [Department of Physics and Astronomy, University of Padova, Via Marzolo 8, 35100 Padova (Italy); INFN, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (Italy); Marchi, T.; Gramegna, F.; Cinausero, M. [INFN, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (Italy); Quaranta, A. [Department of Industrial Engineering, University of Trento, Trento (Italy); INFN, Tifpa, Trento (Italy); Palma, M. Dalla [INFN, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (Italy); Department of Industrial Engineering, University of Trento, Trento (Italy)

2016-07-07

The good light output of siloxane based scintillators as displayed under γ-rays and α particles has been exploited here to obtain clear and reliable response toward thermal neutrons. Sensitization towards thermal neutrons has been pursued by adding {sup 6}LiF, in form of nanoparticles. Aiming at the enhancement of compatibility between the inorganic nanoparticles and the low polarity, siloxane based surrounding medium, oleic acid-capped {sup 6}LiF nanoparticles have been synthesized by thermal decomposition of Li trifluoroacetate. Thin pellets siloxane scintillator maintained their optical transmittance up to weight load of 2% of {sup 6}Li. Thin samples with increasing {sup 6}Li concentration and thicker ones with fixed {sup 6}Li amount have been prepared and tested with several sources (α, γ-rays, moderated neutrons). Light output as high as 80% of EJ212 under α irradiation was measured with thin samples, and negligible changes have been observed as a result of {sup 6}LiF addition. In case of thick samples, severe light loss has been observed, as induced by opacity. Nevertheless, thermal neutrons detection has been assessed and the data have been compared with GS20, based on Li glass, taken as a reference material.

Electrochemical and diffusional insights of combustion synthesized SrLi2Ti6O14 negative insertion material for Li-ion Batteries

Science.gov (United States)

Dayamani, Allumolu; Shinde, Ganesh S.; Chaupatnaik, Anshuman; Rao, R. Prasada; Adams, Stefan; Barpanda, Prabeer

2018-05-01

Solvothermal synthetic routes can provide energy-savvy platforms to fabricate battery anode materials involving relatively milder annealing steps vis-à-vis the conventional solid-state synthesis. These energy efficient routes in turn restrict aggressive grain growth to form nanoscale particles favouring efficient Li+ diffusion. Here, we report an economic solution combustion synthesis of SrLi2Ti6O14 anode involving nitrate-urea complexation with a short annealing duration of only 2 h (900 °C). Rietveld refinement confirms the phase purity of target product assuming an orthorhombic framework (Cmca symmetry). It delivers reversible capacity of ∼125 mAh.g-1 at a rate of C/20 involving a 1.38 V Ti4+/Ti3+ redox activity with excellent rate kinetics and cycling stability. Bond valence site energy (BVSE) calculations gauge SrLi2Ti6O14 to be an anisotropic 3D Li+ ion conductor with the highest ionic conductivity along the c direction. The electrochemical and diffusional pathways have been elucidated for combustion prepared SrLi2Ti6O14 as an efficient and safe negative electrode candidate for Li-ion batteries.

Investigation of the antiprotonic X-ray spectrum of the lithium isotopes 6Li and 7Li

International Nuclear Information System (INIS)

Guigas, R.

1981-09-01

Antiprotons of the low-energy separated anti p-beam K 23 at CERN in Geneva have been stopped in thin (0.6 g/cm 2 ) targets of the Lithium isotopes 6 Li and 7 Li. The characteristic X-rays of the formed antiprotonic atoms were measured with four identical high-resolution Si (Li) detectors. Three lines of the N- series, four lines of the M-series and the 3d-2p transition of the Balmer series were observed. The measured relative intensities of the M- and N-series transitions are well described by the simple cascade model of Eisenberg and Kessler. The 3d-2p transition is considerably influenced by the strong interaction between antiproton and nucleus and thus drastically reduced in intensity. The analysis of this transition yields the shift and width of the 2p level, whereas the width of the 3d level is deduced from intensity considerations. (orig./HSI)

Thermodynamic properties and behaviour of A2[(UO2)(MoO4)2] compounds with A = Li, Na, K, Rb, and Cs

International Nuclear Information System (INIS)

Lelet, Maxim I.; Suleimanov, Evgeny V.; Golubev, Aleksey V.; Geiger, Charles A.; Depmeier, Wulf; Bosbach, Dirk; Alekseev, Evgeny V.

2014-01-01

Highlights: • Low temperature heat capacity of A 2 [(UO 2 )(MoO 4 ) 2 ] (A = Li, Na, K, Rb, and Cs) series was determined. • Enthalpy of formation of Li 2 [(UO 2 )(MoO 4 ) 2 ] was determined by HF solution calorimetry. • Δ f G° (T = 298 K) of all phases from studied series were calculated. - Abstract: A thermodynamic investigation of five alkali-metal uranyl molybdates of the general formula A 2 [(UO 2 )(MoO 4 ) 2 ], where A = Li, Na, K, Rb, and Cs, was undertaken. The various phases were synthesized by solid-state reaction of ANO 3, with A = Li, Na, K, Rb, or Cs, MoO 3 and γ-UO 3 . The synthetic products were characterized by X-ray powder diffraction and X-ray fluorescence methods. The low-temperature heat capacity, S r °, was measured using adiabatic calorimetry from T = (6 to 335) K. Based on these data, the third law entropy at T = 298.15 K, S°, is (345 ± 1) J · K −1 · mol −1 for Li 2 [(UO 2 )(MoO 4 ) 2 ], (373 ± 1) J · K −1 · mol −1 for Na 2 [(UO 2 )(MoO 4 ) 2 ], (390 ± 1) J · K −1 · mol −1 for K 2 [(UO 2 )(MoO 4 ) 2 ], (377 ± 1) J · K −1 · mol −1 for Rb 2 [(UO 2 )(MoO 4 ) 2 ] and (394 ± 1) J · K −1 · mol −1 for Cs 2 [(UO 2 )(MoO 4 ) 2 ]. The enthalpy of formation of Li 2 [(UO 2 )(MoO 4 ) 2 ] was determined using HF solution calorimetry giving Δ f H°(T = 298 K, Li 2 [(UO 2 )(MoO 4 ) 2 ], cr) = −(3456 ± 9) kJ · mol −1 . Using these new experimental results, together with literature data, the Gibbs free energy of formation of each compound was calculated, giving: Δ f G°(T = 298 K, Li 2 [(UO 2 )(MoO 4 ) 2 ], cr) = −(3204 ± 9) kJ · mol −1 , Δ f G°(T = 298 K, Na 2 [(UO 2 )(MoO 4 ) 2 ], cr) = −(3243 ± 2) kJ · mol −1 , Δ f G°(T = 298 K, K 2 [(UO 2 )(MoO 4 ) 2 ], cr) = −(3269 ± 3) kJ · mol −1 , Δ f G°(T = 298 K, Rb 2 [(UO 2 )(MoO 4 ) 2 ], cr) = −(3262 ± 3) kJ · mol −1 , and Δ f G°(T = 298 K, Cs 2 [(UO 2 )(MoO 4 ) 2 ], cr) = −(3259 ± 3) kJ · mol −1 . Smoothed S r °(T) values

Density Functional Theory Study of the Interaction of Hydrogen with Li6C60.

Science.gov (United States)

Wang, Qian; Jena, Puru

2012-05-03

Hydrogen storage properties of Li-coated C60 fullerene have been studied using density functional theory within the local density as well as generalized gradient approximation. Hydrogen atoms are found to bind to Li6C60 in two distinct forms, with the first set attaching to C atoms, not linked to Li, in atomic form. Once all such C atoms are saturated with hydrogen, the second set of hydrogen atoms bind quasi-molecularly to the Li atoms, five of which remain in the exohedral and the sixth in the endohedral position. The corresponding hydrogen gravimetric density in Li6C60H40 is 5 wt %. Desorption of hydrogen takes place in succession, the ones bound quasi-molecularly desorbing at a temperature lower than the ones bound atomically. The results are compared with the recent experiment on hydrogen adsorption in Li6C60.

Vacancy formation energy of Li(H,D) and Na(H,D) systems

International Nuclear Information System (INIS)

Islam, A.K.M.A.

1993-06-01

Vacancy defect formation energy (Schottky defect) of lighter hydrides and deuterides of alkali metals are discussed with reference to conductivity measurements and the recent computer simulation calculations. An empirical relation with Debye temperature is found to yield values of Schottky defect formation energies of Li(H,D) systems in agreement with experiments. The relationship is also utilized to obtain the formation energies for Na(H,D) systems for which experimental values are available in the literature. (author). 37 refs, 1 fig., 1 tab

Gamma-delayed deuteron emission of the 6Li(0+;T=1) halo state

International Nuclear Information System (INIS)

Tursunov, E.M.; Descouvemont, P.; Baye, D.

2007-01-01

M1 transitions from the 6 Li(0 + ;T=1) state at 3.563 MeV to the 6 Li(1 + ) ground state and to the α+d continuum are studied in a three-body model. The bound states are described as an α+n+p system in hyperspherical coordinates on a Lagrange mesh. The ground-state magnetic moment and the gamma width of the 6 Li(0 + ) resonance are well reproduced. The halo-like structure of the 6 Li(0 + ) resonance is confirmed and is probed by the M1 transition probability to the α+d continuum. The spectrum is sensitive to the description of the α+d phase shifts. The corresponding gamma width is around 1.0 meV, with optimal potentials. Charge symmetry is analyzed through a comparison with the β-delayed deuteron spectrum of 6 He. In 6 He, a nearly perfect cancellation effect between short-range and halo contributions was found. A similar analysis for the 6 Li(0 + ;T=1)γ decay is performed; it shows that charge-symmetry breaking at large distances, due to the different binding energies and to different charges, reduces this effect. The present branching ratio Γ γ (0 + →α+d)/Γ γ (0 + →1 + )∼1.3x10 -4 should be observable with current experimental facilities.

Measurement of tritium production in 6LiD irradiated with neutrons from a critical system

International Nuclear Information System (INIS)

Duan Shaojie

1998-03-01

The tritium production rate and its distribution, in a 6 LiD semisphere on a critical assembly neutron source are measured with a 6 Li sandwich gold-silicon surface barrier detector. Then tritium production rate and the average tritium production length of the neutrons in the whole 6 LiD sphere are derived from approximate sphere symmetry

The frequency analysis particle resolution technique of 6LiI(Eu) scintillation detector

International Nuclear Information System (INIS)

Duan Shaojie

1995-01-01

To measure the distribution and rate of tritium production by neutron in a 6 LiD sphere, the 6 LiI(Eu) scintillation detector was used. In the measurement, the frequency analysis particle resolution technique was used. The experiment was completed perfectly

Superconducting instabilities and quasipartical interference in the LiFeAs and Co-doped NaFeAs iron-based superconductors

Energy Technology Data Exchange (ETDEWEB)

Altenfeld, Dustin; Ahn, Felix; Eremin, Ilya [Institut fuer Theoretische Physik III, Ruhr-Universitaet Bochum, D-44801 Bochum (Germany); Borisenko, Sergey [Leibniz-Institute for Solid State Research, IFW-Dresden, D-01171 Dresden (Germany)

2015-07-01

We analyze and compare the structure of the pairing interaction and superconducting gaps in LiFeAs and Co-doped NaFeAs by using the ten-orbital tight-binding model, derived from ab initio LDA calculations with hopping parameters extracted from the fit to ARPES experiments. We discuss the phase diagram and experimental probes to determine the structure of the superconducting gap in these systems with special emphasis on the quasiparticle interference, computed using the T-matrix approximation. In particular, we analyze how the superconducting state with opposite sign of the gaps on the two inner hole pockets in LiFeAs evolve upon changing the parameters towards NaFeAs compound.

Na1.25Ni1.25Fe1.75(PO4)3 nanoparticles as a janus electrode material for Li-ion batteries

Science.gov (United States)

Karegeya, Claude; Mahmoud, Abdelfattah; Hatert, Frédéric; Vertruyen, Bénédicte; Cloots, Rudi; Lippens, Pierre-Emmanuel; Boschini, Frédéric

2018-06-01

A solvothermal method was used to prepare Na1.25Ni1.25Fe1.75(PO4)3 nanoparticles, a new promising electrode material for lithium-ion batteries. The composition and the crystal structure were determined by 57Fe Mössbauer spectroscopy and powder X-ray diffraction Rietveld refinements and confirmed by magnetic measurements. The structural formula □0.75Na1.25Ni1.25Fe1.75(PO4)3 was obtained showing a significant amount of Na vacancies, which enhances Li diffusion. Na1.25Ni1.25Fe1.75(PO4)3 was used as negative and positive electrode material and shows excellent electrochemical performances. As negative electrode in the voltage range 0.03-3.5 V vs. Li+/Li, the first discharge at current density of 40 mA g-1 delivers a specific capacity of 1186 mAh g-1, which is almost three times its theoretical capacity (428 mAh g-1). Then, reversible capacity of 550 mAh g-1 was obtained at 50 mA g-1 with high rate capability (150 mAh g-1 at 500 mA g-1) and capacity retention of 350 cycles. As positive electrode material, specific capacities of about 145 and 99 mAh g-1 were delivered at current densities of 5 and 50 mA g-1, respectively, in the voltage range of 1.5-4.5 V vs. Li+/Li. In addition, we show that the use of solvothermal synthesis contributes to the synthesis of small sized particles leading to good electrochemical performances.

Ce and Eu-doped LiSrAlF6 scintillators for neutron detectors

International Nuclear Information System (INIS)

Yanagida, Takayuki; Kawaguchi, Noriaki; Fujimoto, Yutaka; Yokota, Yuui; Yamazaki, Atsushi; Watanabe, Kenichi; Kamada, Kei; Yoshikawa, Akira; Chani, Valery

2011-01-01

Ce 1%, Eu 1%, and Eu 2%-doped LiSrAlF 6 (LiSAF) single crystals were grown by the micro-pulling-down method for thermal neutron applications. The crystals were transparent, 2.0 mm in diameter and 20–40 mm in length. Neither visible inclusions nor cracks were observed. Their transmittance spectra were measured. The strong absorption lines were observed at 200, 240, and 300 nm for Ce:LiSAF due to Ce 3+ 4f–5d transition. In Eu:LiSAF, 200 (4f–5d) and 300 (4f–4f) nm absorption lines were detected. The samples demonstrated strong emission peaks at 300 nm (Ce:LiSAF) and 370 nm (Eu:LiSAFs) when they were irradiated with 241 Am α-rays simulating the α-particles from the 6 Li(n, α) reaction. Thermal neutron responses were examined under 252 Cf irradiation. The absolute light yield of Ce, Eu 1%, and Eu 2% crystals were 3400, 18000, and 30000 ph/n, respectively. Main components of the scintillation decay time of Ce, Eu 1%, and Eu 2%-doped LiSAFs were 63, 1293, and 1205 ns.

Influence of the α-d motion in 6Li on Trojan horse applications

International Nuclear Information System (INIS)

Pizzone, R.G.; Spitaleri, C.; Cherubini, S.; La Cognata, M.; Lamia, L.; Musumarra, A.; Romano, S.; Tumino, A.; Tudisco, S.; Miljanic, D.; Typel, S.

2005-01-01

The α-d cluster structure of 6 Li has been extensively investigated in the past few decades. In particular the width of the α momentum distribution in 6 Li has been studied as a function of the transferred momentum. These investigations are now reviewed and updated after recent experiments. Trojan horse method applications are also discussed because the momentum distribution of the spectator particle inside the Trojan horse nucleus is a necessary input for this method. The impact of the width (FWHM) variation in the extraction of the astrophysical S(E) factor is discussed for the 6 Li(d,α) 4 He reaction

Improved the lithium storage capability of BaLi2Ti6O14 by electroless silver coating

International Nuclear Information System (INIS)

Lin, Xiaoting; Wang, Pengfei; Li, Peng; Yu, Haoxiang; Qian, Shangshu; Shui, Miao; Wang, Dongjie; Long, Nengbing; Shu, Jie

2015-01-01

Highlights: • BaLi 2 Ti 6 O 14 /Ag is fabricated via a facile electroless deposition. • Highly dispersed Ag nanoparticles are successively coated on BaLi 2 Ti 6 O 14 . • BaLi 2 Ti 6 O 14 /Ag is used as anode material for lithium storage. • BaLi 2 Ti 6 O 14 /Ag exhibits improved lithium storage capability. - Abstract: To form BaLi 2 Ti 6 O 14 /Ag, highly dispersed Ag nanoparticles are successfully deposited on the surface of BaLi 2 Ti 6 O 14 by a simple chemical deposition method. The morphology, quantity and size of Ag nanoparticles in BaLi 2 Ti 6 O 14 /Ag composites are significantly influenced by the Ag coating contents. Electrochemical results show that Ag nanoparticles play a positive role in reducing redox polarization and improving electrical conductivity of BaLi 2 Ti 6 O 14 during lithiation/delithiation processes. Among all the as-obtained products, 6 wt.% Ag coated BaLi 2 Ti 6 O 14 shows the highest initial charge specific capacity of 160 mAh g −1 at the current density of 100 mA g −1 (1C), which is much higher than the 149.1 mAh g −1 for bare BaLi 2 Ti 6 O 14 . After 100 charge/discharge cycles, the reversible capacity can be maintained at 117.0 mAh g −1 . Moreover, this sample also shows excellent rate performance with high reversible charge capacities of 147.5, 139.7, 132.6, and 126.7 mAh g −1 at the rates of 2C, 3C, 4C and 5C, respectively. Compared with bare BaLi 2 Ti 6 O 14 , the superior electrochemical performance indicates that BaLi 2 Ti 6 O 14 /Ag can be a good anode material in lithium ion batteries.

Orientation and alignment of the first excited p state in Li+He and Na+He scattering

International Nuclear Information System (INIS)

Archer, B.J.; Lane, N.F.; Kimura, M.

1990-01-01

Orientation and alignment parameters for the first excited p state of Li and Na in collisions with He through direct excitation from the ground state are studied theoretically in the energy region up to E c.m. =100 keV by using a quasi-one-electron theory. Scattering states are expanded in terms of molecular orbitals, which are calculated by using the pseudopotential method and include electron translation factors. The approach appears to work well for Li+He, giving good agreement for the 2p excitation probability and orientation. For alignment, the situation is less clear because of difficulty in experimental measurement. Two-electron effects and cascades from more highly excited states cause our description of Na+He collisions to be less satisfactory. However, agreement with the experimental 3p excitation probability and orientation parameters where all data are available is fairly good at lower energies (E c.m. 1.25 a.u.)

Simultaneous solution to the 6Li and 7Li big bang nucleosynthesis problems from a long-lived negatively charged leptonic particle

International Nuclear Information System (INIS)

Kusakabe, Motohiko; Kajino, Toshitaka; Boyd, Richard N.; Yoshida, Takashi; Mathews, Grant J.

2007-01-01

The 6 Li abundance observed in metal-poor halo stars exhibits a plateau similar to that for 7 Li suggesting a primordial origin. However, the observed abundance of 6 Li is a factor of 10 3 larger and that of 7 Li is a factor of 3 lower than the abundances predicted in the standard big bang when the baryon-to-photon ratio is fixed by Wilkinson microwave anisotropy probe. Here we show that both of these abundance anomalies can be explained by the existence of a long-lived massive, negatively charged leptonic particle during nucleosynthesis. Such particles would capture onto the synthesized nuclei thereby reducing the reaction Coulomb barriers and opening new transfer reaction possibilities, and catalyzing a second round of big bang nucleosynthesis. This novel solution to both of the Li problems can be achieved with or without the additional effects of stellar destruction

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.

Triple-differential cross section of the 208Pb(6Li, αd)208 Pb Coulomb breakup and astrophysical S-factor of the d(α,γ)6 Li reaction at extremely low energies

International Nuclear Information System (INIS)

Igamov, S.B.; Yarmukhamedov, R.

1999-10-01

A method of calculation of the triple-differential cross section of the 208 Pb( 6 Li, αd) 208 Pb Coulomb breakup at astrophysically relevant energies E of the relative motion of the breakup fragments, taking into account the three-body (α - d - 208 Pb) Coulomb effects and the contributions from the E1- and E2- multipoles, including their interference, has been proposed. The new results for the astrophysical S-factor of the direct radiative capture d(α, γ) 6 Li reaction at E ≤ 250 keV have been obtained. It is shown that the experimental triple-differential cross section of the 208 Pb( 6 Li, αd) 208 Pb Coulomb breakup can also be used to give information about the value of the modulus squared of the nuclear vertex constant for the virtual 6 Li → α + d. (author)

Si(Li)-NaI(Tl) sandwich detector array for measurements of trace radionuclides in soil samples

International Nuclear Information System (INIS)

Strauss, M.G.; Sherman, I.S.; Roche, C.T.; Pehl, R.H.

1986-01-01

An ultra-sensitive X/γ-ray detector system for assaying trace radioactivity in actinide contaminated soil and ash samples has been developed. The new system consists of an array of 6 large Si(Li) X-ray detectors sensitive on both faces and mounted on edge in a paddle-shaped cryostat with a 14 cm diameter Be window on each side. The paddle, with a sample of the soil placed at each window, is sandwiched between 2 large NaI(Tl) scintillators which suppress the γ background. With X-rays being measured simultaneously from soil in 2 sample holders and background reduced by 50% using anticoincidence, the sensitivity of this detector is 4 times higher than that of conventionally mounted Si(Li) detectors. A soil sample containing 50 pCi/g 239 Pu was measured in 5 min with an uncertainty of 1 and NpLsub(β1) X-ray peaks are resolved thus permitting measurement of trace Pu in the presence of 241 Am. This is the most sensitive and selective detector known for nondestructive assay of radioactivity in soil and other samples. (orig.)

Density of Na2O-Li2O-SiO2-B2O3 Molten Slag at 1 803-1 873 K

Institute of Scientific and Technical Information of China (English)

XIAO Feng; FANG Liang

2004-01-01

The density of three kinds of molten slags was measured by modified sessile drop method at 1 803-1 873 K. The density of molten slag is found to decrease with increasing temperature. The temperature coefficients of Na2O-Li2O-SiO2 and Li2O-SiO2-B2O3 slag are smaller than that of Na2O-B2O3 slag. The molar volume of slags increases with increasing temperature.

Syntheses and structural characterization of non-centrosymmetric Na{sub 2}M{sub 2}M'S{sub 6} (M, M′=Ga, In, Si, Ge, Sn, Zn, Cd) sulfides

Energy Technology Data Exchange (ETDEWEB)

Yohannan, Jinu P.; Vidyasagar, Kanamaluru, E-mail: kvsagar@iitm.ac.in

2016-06-15

Seven new non-centrosymmetric Na{sub 2}M{sub 2}M’S{sub 6} sulfides, namely, Na{sub 2}Sn{sub 2}ZnS{sub 6}(1){sub ,} Na{sub 2}Ga{sub 2}GeS{sub 6}(2), Na{sub 2}Ga{sub 2}SnS{sub 6}(3-α), Na{sub 2}Ga{sub 2}SnS{sub 6}(3-β){sub ,} Na{sub 2}Ge{sub 2}ZnS{sub 6}(4){sub ,} Na{sub 2}Ge{sub 2}CdS{sub 6}(5){sub ,} Na{sub 2}In{sub 2}SiS{sub 6}(6) and Na{sub 2}In{sub 2}GeS{sub 6}(7), were synthesized by high temperature solid state reactions and structurally characterized by single crystal X-ray diffraction. They crystallize in non-centrosymmetric Fdd2 and Cc space groups and their three-dimensional [M{sub 2}M′S{sub 6}]{sup 2-}framework structures consist of MS{sub 4} and M′S{sub 4} tetrahedra corner-connected to one another in either orderly or disordered fashion. Sodium ions reside in the tunnels of the anionic framework. Compounds 1, 2 and 3-α have the structure of known Li{sub 2}Ga{sub 2}GeS{sub 6}, whereas compounds 6 and 7 are isostructural with known Li{sub 2}In{sub 2}GeS{sub 6} compound. Isostructural compounds 4 and 5 represent a new structural variant. Compounds 3-α and its new monoclinic structural variant 3-β have disordered structural framework. All of them are wide band gap semiconductors. Na{sub 2}Ga{sub 2}GeS{sub 6}(2), Na{sub 2}Ga{sub 2}SnS{sub 6}(3), Na{sub 2}Ge{sub 2}ZnS{sub 6}(4) and Na{sub 2}In{sub 2}GeS{sub 6}(7) compounds are found to be second-harmonic generation (SHG) active. Compounds 1, 2 and 3-α melt congruently. - Graphical abstract: Na{sub 2}Ga{sub 2}GeS{sub 6}, Na{sub 2}Ga{sub 2}SnS{sub 6}, Na{sub 2}Ge{sub 2}ZnS{sub 6}, Na{sub 2}In{sub 2}GeS{sub 6}, Na{sub 2}Sn{sub 2}ZnS{sub 6}, Na{sub 2}Ge{sub 2}CdS{sub 6} and Na{sub 2}In{sub 2}SiS{sub 6} have non-centrosymmetric structures and the first four compounds are SHG active. Display Omitted - Highlights: • Seven new Na{sub 2}M{sub 2}M′S{sub 6} compounds with non-centrosymmetric structures were synthesized. • They are wide band gap semiconductors. • Na{sub 2}Ga{sub 2}GeS{sub 6}, Na{sub 2

Reaction channels of 6,7Li+28Si at near-barrier energies

International Nuclear Information System (INIS)

Pakou, A; Rusek, K; Nicolis, N G; Alamanos, N; Doukelis, G; Gillibert, A; Kalyva, G; Kokkoris, M; Lagoyannis, A; Musumarra, A; Papachristodoulou, C; Perdikakis, G; Pierroutsakou, D; Pollacco, E C; Spyrou, A; Zarkadas, Ch

2005-01-01

The production of α-particles in the reactions 6,7 Li+ 28 Si was studied as a means to disentangle the various reaction channels at near-barrier energies. The competition between compound and direct reactions was determined by using the shape of angular distributions and statistical model calculations. DWBA calculations were also performed to probe the various direct channels. It was found that, approaching barrier, transfer channels are the most dominant for both reactions. For 7 Li+ 28 Si d-transfer is one of the contributing channels without excluding t-transfer, while for 6 Li+ 28 Si, n-transfer and p-transfer have substantial contribution but without excluding d-transfer

Data for the neutron interactions with 6Li and 10B

International Nuclear Information System (INIS)

Poenitz, W.P.

1984-01-01

The 10 B(n,α), 10 B(n,α 1 ) and, increasingly in more recent measurement, the 6 Li(n,α) cross sections are the major references used in low energy experiments. Many data from modern measurements are available for the neutron interaction with 6 Li, including total, scattering, and absolute and relative (n,α) cross sections. A consensus has been reached with these new 6 Li + n data. In contrast, the data base for the 10 B neutron interaction cross sections is unfortunately poor. This is even the case for the total cross section which is supposed to be the easiest quantity to be measured. The most serious deficiency is the absence of data from absolute measurements of the 10 B(n,α) and 10 B(n,α 1 ) cross sections in the last 10 to 15 years. The available cross section data which were used for the ENDF/B-VI evaluation will be discussed. 43 references

Spin response in LiFeAs and NaFeAs iron-pnictides superconductors

Energy Technology Data Exchange (ETDEWEB)

Lochner, Felix; Ahn, Felix; Eremin, Ilya [Ruhr-Universitaet Bochum, Bochum (Germany)

2016-07-01

We analyze the spin susceptibility in LiFeAs and NaFeAs by using the ten-orbital tight-binding model that we fitted to the electronic band structure measured by recent ARPES experiments. We identify an effective five-band model for a weak k{sub z}-dependence. Besides we present the bare and RPA-susceptibility and its q{sub z} dependencies to study the magnetic instabilities and estimate the strength of intra-orbital and inter-orbital nesting.

Observation of superconductivity at 30∼46K in AxFe2Se2 (A = Li, Na, Ba, Sr, Ca, Yb, and Eu)

OpenAIRE

Ying, T. P.; Chen, X. L.; Wang, G.; Jin, S. F.; Zhou, T. T.; Lai, X. F.; Zhang, H.; Wang, W. Y.

2012-01-01

New iron selenide superconductors by intercalating smaller-sized alkali metals (Li, Na) and alkaline earths using high-temperature routes have been pursued ever since the discovery of superconductivity at about 30 K in KFe2Se2, but all have failed so far. Here we demonstrate that a series of superconductors with enhanced Tc=30~46 K can be obtained by intercalating metals, Li, Na, Ba, Sr, Ca, Yb, and Eu in between FeSe layers by the ammonothermal method at room temperature. Analysis on their p...

Li+ solvation and kinetics of Li+-BF4-/PF6- ion pairs in ethylene carbonate. A molecular dynamics study with classical rate theories

Science.gov (United States)

Chang, Tsun-Mei; Dang, Liem X.

2017-10-01

Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ethylene carbonate (EC) exchange process between the first and second solvation shells around Li+ and the dissociation kinetics of ion pairs Li+-[BF4] and Li+-[PF6] in this solvent. We calculate the exchange rates using transition state theory and correct them with transmission coefficients computed by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found that the residence times of EC around Li+ ions varied from 60 to 450 ps, depending on the correction method used. We found that the relaxation times changed significantly from Li+-[BF4] to Li+-[PF6] ion pairs in EC. Our results also show that, in addition to affecting the free energy of dissociation in EC, the anion type also significantly influences the dissociation kinetics of ion pairing.

The pentasulfates A{sub 2}[S{sub 5}O{sub 16}] (A = Li, Na, Cs, Ag). Rare species by reactions in SO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Schindler, Lisa Verena; Struckmann, Mona; Becker, Anna; Wickleder, Mathias S. [Institute of Inorganic and Analytical Chemistry, Justus Liebig University of Giessen (Germany)

2017-02-03

The reaction of various sulfate salts A{sub 2}SO{sub 4} (A = Li, Na, Ag, Cs) with neat SO{sub 3} led to the respective pentasulfates A{sub 2}[S{sub 5}O{sub 16}] {Li_2[S_5O_1_6]: monoclinic, C2/c, Z = 4, a = 1850.71(7) pm, b = 665.45(2) pm, c = 992.80(4) pm, β = 106.764(2) , V = 1170.72(7) x 10"6 pm"3; Na_2[S_5O_1_6]: orthorhombic, Pbcn, Z = 4, a = 880.17(3) pm, b = 1039.88(4) pm, c = 1348.58(5) pm, V = 1234.32(8) x 10"6 pm"3; Ag_2[S_5O_1_6]: orthorhombic, Pbcn, Z = 4, a = 884.34(4) pm, b = 1043.19(5) pm, c = 1381.83(7) pm, V = 1274.8(1) x 10"6 pm"3; Cs_2[S_5O_1_6]: monoclinic, P2_1, Z = 4, a = 892.96(3) pm, b = 859.72(3) pm, c = 978.30(4) pm, β = 101.443(2) , V = 736.11(5) x 10"6 pm"3}. All four compounds are colorless and extremely moisture-sensitive substances. They all contain the pentasulfate anion [S{sub 5}O{sub 16}]{sup 2-} that has, until now, only been reported once. This comparative study of polysulfate salts with the same polysulfate anion, but varying countercations, is a crucial step in comprehending this very basic and, nevertheless, poorly investigated class of materials. Raman spectroscopy and powder diffraction complete the structural investigations. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Laser-diode-excited blue upconversion in Tm3+/Yb3+ -codoped TeO2-Ga2O3-R2O (R=Li, Na, K) glasses.

Science.gov (United States)

Zhao, Chun; Zhang, Qinyuan; Yang, Gangfeng; Jiang, Zhonghong

2008-01-01

This paper reports on intense blue upconversion in Tm(3+)/Yb(3+) codoped TeO(2)-Ga(2)O(3)-R(2)O(R=Li, Na, K) glasses upon excitation with commercial available laser diode (LD). Effects of alkali ions on the Raman spectra, thermal stability and spectroscopic properties of the tellurite-gallium glasses have also been investigated. Energy transfer and the involved upconversion mechanisms have been discussed. Intense blue upconversion emission centered at 476 nm along with a weak red emission at 650 nm has been observed upon excitation of 977 nm LD, assigned to the transitions of 1G4-->3H6, and 1G4-->3H4 and/or 3F(2,3)-->3H6 of Tm(3+), respectively. The blue upconversion intensity has a cubelike dependence on incident pump laser power, indicating a three-photon process. However, a quadratic dependence of the 476 nm upconversion intensity on the incident pump laser power has been observed when samples under excitation of 808 nm LD due to a two-photon absorption process. Enhanced upconversion luminescence have been observed with replacing K(+) for Na(+) and Li(+).

Structure and stability of small Li2 +(X2Σ+ g )-Xen (n = 1-6) clusters

Science.gov (United States)

Saidi, Sameh; Ghanmi, Chedli; Berriche, Hamid

2014-04-01

We have studied the structure and stability of the Li2 +(X2Σ+ g )Xe n ( n = 1-6) clusters for special symmetry groups. The potential energy surfaces of these clusters, are described using an accurate ab initio approach based on non-empirical pseudopotential, parameterized l-dependent polarization potential and analytic potential forms for the Li+Xe and Xe-Xe interactions. The pseudopotential technique has reduced the number of active electrons of Li2 +(X2Σ+ g )-Xe n ( n = 1-6) clusters to only one electron, the Li valence electron. The core-core interactions for Li+Xe are included using accurate CCSD(T) potential fitted using the analytical form of Tang and Toennies. For the Xe-Xe potential interactions we have used the analytical form of Lennard Jones (LJ6 - 12). The potential energy surfaces of the Li2 +(X2Σ+ g )Xe n ( n = 1-6) clusters are performed for a fixed distance of the Li2 +(X2Σ+ g ) alkali dimer, its equilibrium distance. They are used to extract information on the stability of the Li2 +(X2Σ+ g Xe n ( n = 1-6) clusters. For each n, the stability of the different isomers is examined by comparing their potential energy surfaces. Moreover, we have determined the quantum energies ( D 0), the zero-point-energies (ZPE) and the ZPE%. To our best knowledge, there are neither experimental nor theoretical works realized for the Li2 +(X2Σ+ g Xe n ( n = 1-6) clusters, our results are presented for the first time.

Enhance luminescence by introducing alkali metal ions (R+ = Li+, Na+ and K+) in SrAl2O4:Eu3+ phosphor by solid-state reaction method

Science.gov (United States)

Prasad Sahu, Ishwar

2016-05-01

In the present article, the role of charge compensator ions (R+ = Li+, Na+ and K+) in europium-doped strontium aluminate (SrAl2O4:Eu3+) phosphors was synthesized by the high-temperature, solid-state reaction method. The crystal structures of sintered phosphors were in a monoclinic phase with space group P21. The trap parameters which are mainly activation energy (E), frequency factor (s) and order of the kinetics (b) were evaluated by using the peak shape method. The calculated trap depths are in the range from 0.76 to 0.84 eV. Photoluminescence measurements showed that the phosphor exhibited emission peak with good intensity at 595 nm, corresponding to 5D0-7F1 (514 nm) orange emission and weak 5D0-7F2 (614 nm) red emission. The excitation spectra monitored at 595 nm show a broad band from 220 to 320 nm ascribed to O-Eu charge-transfer state transition and the other peaks in the range of 350-500 nm originated from f-f transitions of Eu3+ ions. The strongest band at 394 nm can be assigned to 7F0-5L6 transition of Eu3+ ions due to the typical f-f transitions within Eu3+ of 4f6 configuration. The latter lies in near ultraviolet (350-500 nm) emission of UV LED. CIE color chromaticity diagram and thermoluminescence spectra confirm that the synthesized phosphors would emit an orange-red color. Incorporating R+ = Li+, Na+ and K+ as the compensator charge, the emission intensity of SrAl2O4:Eu3+ phosphor can be obviously enhanced and the emission intensity of SrAl2O4:Eu3+ doping Li+ is higher than that of Na+ or K+ ions.

Fusion spectrum neutron source computation in "6LiD convertor for HFETR

International Nuclear Information System (INIS)

Sun Shouhua; Hu Yifei; Ye Bin

2014-01-01

A computation model of 14 MeV neutron from the "6LiD convertor has been established, the 14 MeV neutron sources and flux in the irradiation samples from the "6LiD convertor and the core have been computed separately, the neutron spectrum in the irradiation samples have been computed, too. The results show that the neutron sources that over 13 MeV account for 1 MeV above in the "6LiD convertor is 25.7%, 24.6% respectively, 14 MeV neutron sources get 4.31 × 10"1"3 n_T·s"-"1, 3.34 × 10"1"3 n_T·s"-"1, 14 MeV neutron flux get 2.66 × 10"1"0 n_T·cm"-"2·s"-"1, 3.53 × 10"1"0 n_T·cm"-"2·s"-"1, as He and H_2O charged in the irradiation capsule. (authors)

Fusion of 6Li with 159Tb at near-barrier energies

International Nuclear Information System (INIS)

Pradhan, M. K.; Mukherjee, A.; Basu, P.; Goswami, A.; Kshetri, R.; Roy, Subinit; Chowdhury, P. Roy; Sarkar, M. Saha; Palit, R.; Parkar, V. V.; Santra, S.; Ray, M.

2011-01-01

Complete and incomplete fusion cross sections for 6 Li + 159 Tb have been measured at energies around the Coulomb barrier by the γ-ray method. The measurements show that the complete fusion cross sections at above-barrier energies are suppressed by ∼34% compared to coupled-channel calculations. A comparison of the complete fusion cross sections at above-barrier energies with the existing data for 11,10 B + 159 Tb and 7 Li + 159 Tb shows that the extent of suppression is correlated with the α separation energies of the projectiles. It has been argued that the Dy isotopes produced in the reaction 6 Li + 159 Tb at below-barrier energies are primarily due to the d transfer to unbound states of 159 Tb, while both transfer and incomplete fusion processes contribute at above-barrier energies.

Exploring incomplete fusion fraction in 6,7Li induced nuclear reactions

Science.gov (United States)

Parkar, V. V.; Jha, V.; Kailas, S.

2017-11-01

We have included breakup effects explicitly to simultaneously calculate the measured cross-sections of the complete fusion, incomplete fusion, and total fusion for 6,7Li projectiles on various targets using the Continuum Discretized Coupled Channels method. The breakup absorption cross-sections obtained with different choices of short range imaginary potentials are utilized to evaluate the individual α-capture and d/t-capture cross-sections and compare with the measured data. It is interesting to note, while in case of 7Li projectile the cross-sections for triton-ICF/triton-capture is far more dominant than α-ICF/α-capture at all energies, similar behavior is not observed in case of 6Li projectile for the deuteron-ICF/deuteron-capture and α-ICF/α-capture. Both these observations are also corroborated by the experimental data for all the systems studied.

Exploring incomplete fusion fraction in 6,7Li induced nuclear reactions

Directory of Open Access Journals (Sweden)

Parkar V. V.

2017-01-01

Full Text Available We have included breakup effects explicitly to simultaneously calculate the measured cross-sections of the complete fusion, incomplete fusion, and total fusion for 6,7Li projectiles on various targets using the Continuum Discretized Coupled Channels method. The breakup absorption cross-sections obtained with different choices of short range imaginary potentials are utilized to evaluate the individual α-capture and d/t-capture cross-sections and compare with the measured data. It is interesting to note, while in case of 7Li projectile the cross-sections for triton-ICF/triton-capture is far more dominant than α-ICF/α-capture at all energies, similar behavior is not observed in case of 6Li projectile for the deuteron-ICF/deuteron-capture and α-ICF/α-capture. Both these observations are also corroborated by the experimental data for all the systems studied.

Trojan horse particle invariance studied with the 6Li(d,α)4He and 7Li(p,α)4He reactions

International Nuclear Information System (INIS)

Pizzone, R. G.; Spitaleri, C.; Lamia, L.; Cherubini, S.; La Cognata, M.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Piskor, S.; Kiss, G. G.; Li, C.; Tumino, A.

2011-01-01

The Trojan horse nucleus invariance for the binary reaction cross section extracted from the Trojan horse reaction was tested using the quasifree 3 He( 6 Li,αα)H and 3 He( 7 Li,αα) 2 H reactions. The cross sections for the 6 Li(d,α) 4 He and 7 Li(p,α) 4 He binary processes were extracted in the framework of the plane wave approximation. They are compared with direct behaviors as well as with cross sections extracted from previous indirect investigations of the same binary reactions using deuteron as the Trojan horse nucleus instead of 3 He. The very good agreement confirms the applicability of the plane wave approximation which suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus, at least for the investigated cases.

Neutron spatial distribution measurement with 6Li-contained thermoluminescent sheets

International Nuclear Information System (INIS)

Konnai, A.; Odano, N.; Sawamura, H.; Ozasa, N.; Ishikawa, Y.

2006-01-01

We have been developing a thermoluminescent (TL) sheet for photon dosimetry (TL sheet) with thermoluminescent material of LiF:Mg, Cu, P and a co-polymer of ethylene and tetrafluoroethylene. For the purpose of a development of simple method for neutron spatial distribution measurement, TL sheet for neutron detection (NTL sheet) is made by adding 94.7% enriched 6 LiF to TL sheet. TL material in TL sheet is directly excited by ionizing radiation whereas, in the case of neutron detection, TL material in NTL sheet is indirectly excited by neutron capture reaction. That is neutron distribution can be obtained with TL caused by α particle from 6 Li(n, α) 3 H reaction. Responses of NTL sheets to neutrons were examined at the neutron beam irradiation facility for Boron Neutron Capture Therapy (BNCT) in JRR-4 research reactor in Japan Atomic Energy Agency. TL and NTL sheets were exposed to striped and roundly distributed neutron fields. Attenuations of neutron flux in air and water were also observed using NTL sheets. TL sheets were also exposed on the same conditions and compared with NTL sheets. TL intensity ratios of NTL sheet to TL sheet were consistent with the calculated value from 6 Li content. Thermal neutron attenuation observed by NTL sheet also corresponded with the result measured by Au wire radioactivation and TLD chips, which were currently used in BNCT at JRR-4. These results were analyzed with by Monte Carlo simulation. The present results indicated that NTL sheet is applicable to measurement of neutron spatial distribution. (author)

Energy dependence of the 3He(3He,π+)6Li reaction

International Nuclear Information System (INIS)

Le Bornec, Y.; Hibou, F.; Bimbot, L.; Hennino, T.; Jourdain, J.C.; Reide, F.; Tatischeff, B.; Willis, N.; Aslanides, E.; Bergdolt, G.; Fassnacht, P.; Racca, C.; Boudard, A.; Bruge, G.; Lugol, J.C.

1983-01-01

The 3 He( 3 He, π + ) 6 Li reaction has been studied as a function of energy using the 3 He beam at SATURNE. Cross sections for the 6 Li ground state (1 + ) and 2.18 MeV (3 + ) levels have been obtained at 350, 420, 500 and 600 MeV incident energies at angles THETAsub(π)(lab)=15 0 and 40 0 . These results are compared with two theoretical predictions. (orig.)

Application of the three-body model to the reactions 6Li(3He,t 3He)3He and 6Li(3He,3He3He)3H

International Nuclear Information System (INIS)

Haftel, M.I.; Allas, R.G.; Beach, L.A.; Bondelid, R.O.; Petersen, E.L.; Slaus, I.; Lambert, J.M.; Treado, P.A.

1977-01-01

Experimental and theoretical cross sections are presented for the 6 Li( 3 He, 3 He 3 He) 3 H and 6 Li( 3 He,t 3 He) 3 He reactions for the symmetric angle pairs 20 0 -20 0 , 28.3 0 -28.3 0 , and 35 0 -35 0 . The theoretical cross sections are calculated in a three-body model where the trions (i.e., mass-3 nuclei) are treated as elementary particles with 6 Li being a 3 He- 3 H bound state. The trion-trion interaction is represented by S wave separable potentials with the breakup cross sections calculated with the tree-body Haftel-Ebenhoeh code. the Coulomb interaction is taken into account by fitting the separable potential parameters to the trion-trion scattering data and is included approximately in the breakup code. The experimental cross sections are compared with both the plane-wave impulse approximation and the three-body model predictions. The plane-wave impulse approximation predicts both the shapes and magnitudes poorly (10 to 20 times experiment). Without Coulomb corrections the three-body model gives good agreement with experiment for the shapes of the spectra with the magnitudes generally being about 40% of experiment for 6 Li( 3 He, 3 He 3 He) 3 H and about 80% for 6 Li( 3 He,t 3 He) 3 He. The Coulomb corrections improve the magnitudes predicted by the three-body model but not the shapes. It is observed that for these reactions S wave separable potentials describe the breakup data much better than they do the two-body trion-trion scattering data. This result should encourage further three-body treatment of these and similar reactions

Synthesis of high-purity Li{sub 8}ZrO{sub 6} powder by solid state reaction under hydrogen atmosphere

Energy Technology Data Exchange (ETDEWEB)

Shin-mura, Kiyoto; Otani, Yu; Ogawa, Seiya [Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Niwa, Eiki; Hashimoto, Takuya [Department of Physics, College of Humanities and Sciences, Nihon University, 3-8-1 Sakurajousui, Setagaya-ku, Tokyo 156-8550 (Japan); Hoshino, Tsuyoshi [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Sector of Fusion Research and Development, Japan Atomic Energy Agency, 2-166 Obuchi, Omotedate, Rokkasho-mura, Kamikita-gun, Aomori 039-3212 (Japan); Sasaki, Kazuya, E-mail: k_sasaki@tokai-u.ac.jp [Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Department of Prime Mover Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

2016-11-01

Highlights: • A fine pure Li{sub 8}ZrO{sub 6} powder was synthesized by using Li{sub 2}CO{sub 3} and ZrO{sub 2} via a solid state reaction. • Influences on the purity of product powder, lattice defect, and crystal orientation were revealed. • The suitable synthesis conditions of the fine and high purity Li{sub 8}ZrO{sub 6} powder were found. • The reaction process of the synthesis of Li{sub 8}ZrO{sub 6} was estimated. - Abstract: Li{sub 8}ZrO{sub 6} contains a large amount of Li and has a significant potential as a tritium breeder. However, few syntheses of fine-grain, high-purity Li{sub 8}ZrO{sub 6} powder have been reported. In this study, a high-purity powder of Li{sub 8}ZrO{sub 6} was synthesized by solid state reaction under hydrogen atmosphere combined with an effective lithium source and a suitable initial Li:Zr molar ratio. Mixed powders of Li{sub 2}CO{sub 3} and ZrO{sub 2} were fired at around 630 °C in H{sub 2} for several hours and several firing cycles. The low firing temperature inhibited the vaporization of Li during the heating, so that excessive amounts of Li were not needed for the synthesis, and the Li:Zr ratio in the starting material was 10:1 (mol:mol). In this synthesis, Li{sub 2}O was generated via the decomposition of Li{sub 2}CO{sub 3} during firing in H{sub 2}, and reacted with ZrO{sub 2} to form Li{sub 6}Zr{sub 2}O{sub 7}, which reacted with itself to form Li{sub 8}ZrO{sub 6}.

Unified description of ^{6}Li structure and deuterium-^{4}He dynamics with chiral two- and three-nucleon forces.

Science.gov (United States)

Hupin, Guillaume; Quaglioni, Sofia; Navrátil, Petr

2015-05-29

We provide a unified ab initio description of the ^{6}Li ground state and elastic scattering of deuterium (d) on ^{4}He (α) using two- and three-nucleon forces from chiral effective field theory. We analyze the influence of the three-nucleon force and reveal the role of continuum degrees of freedom in shaping the low-lying spectrum of ^{6}Li. The calculation reproduces the empirical binding energy of ^{6}Li, yielding an asymptotic D- to S-state ratio of the ^{6}Li wave function in the d+α configuration of -0.027, in agreement with a determination from ^{6}Li-^{4}He elastic scattering, but overestimates the excitation energy of the 3^{+} state by 350 keV. The bulk of the computed differential cross section is in good agreement with data. These results endorse the application of the present approach to the evaluation of the ^{2}H(α,γ)^{6}Li radiative capture, responsible for the big-bang nucleosynthesis of ^{6}Li.

Thermoluminescence of LiNaSo4: TI after exposure to radiation doses from electrons of different energies

International Nuclear Information System (INIS)

El-Kolaly, M.A.

2002-01-01

Lithium sodium sulphate doped by rare impurities (LiNaSO 4 : TI) has been locally prepared. Its Thermoluminescence properties (TL) have been performed from room temperature up to 300 degree C. The used heating rate was 5 degree C/sec. The samples were irradiated by electrons of different energies (5, 7, 9 and 13 MeV.). These samples were exposed to different duration to attain different radiation doses. It has been observed that the glow curves are consisted of four glow peaks at 75, 125, 225 and 250 degree C respectively. The first peak showed a linear dependence with electron radiation doses and can be used in radiation measurement. The irradiated impurities LiNaSO 4 : TI with energies higher than 5 MeV showed no appreciable change in the TL peak height. The obtained results will explore the probability of using such system (double sulphates doped by rare earth impurities) in the field of radiation measurements

Modeling the degradation mechanisms of C6/LiFePO4 batteries

NARCIS (Netherlands)

Li, D.; Danilov, D.L.; Zwikirsch, B.; Fichtner, M.; Yang, Y.; Eichel, R.A.; Notten, P.H.L.

2018-01-01

A fundamental electrochemical model is developed, describing the capacity fade of C6/LiFePO4 batteries as a function of calendar time and cycling conditions. At moderate temperatures the capacity losses are mainly attributed to Li immobilization in Solid-Electrolyte-Interface (SEI) layers at the

Effects of the co-addition of LiSbO3-LiTaO3 on the densification of (Na1/2K1/2)NbO3 lead free ceramics by atmosphere sintering

International Nuclear Information System (INIS)

Jiang Na; Fang Bijun; Wu Jian; Du Qingbo

2011-01-01

Research highlights: → This manuscript shows a synthesis method that can easily obtain excellent lead-free samples, which is valuable for industrial production. → Pure phase perovskite 0.94(Na 1/2 K 1/2 )NbO 3 -0.03LiSbO 3 -0.03LiTaO 3 (0.94NKN-0.03LS-0.03LT) lead-free piezoelectric ceramics with high relative density, being 94.73%, and excellent integral electrical properties, piezoelectric constant d 33 being 228 pC/N, were prepared by atmosphere sintering method. Which can be attributed to the co-doping of LiSbO 3 -LiTaO 3 . - Abstract: Pure phase perovskite 0.94(Na 1/2 K 1/2 )NbO 3 -0.03LiSbO 3 -0.03LiTaO 3 (0.94NKN-0.03LS-0.03LT) lead-free piezoelectric ceramics were prepared by the conventional solid-state reaction method. Due to the co-addition of LiSbO 3 -LiTaO 3 , the 0.94NKN-0.03LS-0.03LT ceramics prepared by atmosphere sintering at 1040 deg. C exhibit high relative density, being 94.73%, and rather homogenous microstructure. X-ray diffraction (XRD) measurement confirmed that the sintered ceramics exhibit pure tetragonal perovskite structure. The 0.94NKN-0.03LS-0.03LT ceramics exhibit excellent integral electrical properties, in which the value of piezoelectric constant d 33 is 228 pC/N, the electromechanical coupling factors K p and K t are 0.220 and 0.230, respectively, the mechanical quality factor Q m is 32.19, and the remnant polarization P r is 23.06 μC/cm 2 . Such excellent electrical properties are considered as correlating with the high relative density of the synthesized ceramics induced by the co-doping of LiSbO 3 -LiTaO 3 .

Concentration dependence of physical properties of liquid NaF–LiF–NdF{sub 3} alloys

Energy Technology Data Exchange (ETDEWEB)

Bulavin, L. [Kyiv National Taras Shevchenko University, Faculty of Physics, 2 Glushkova Ave., 03022 Kyiv (Ukraine); Plevachuk, Yu., E-mail: plevachuk@mail.lviv.ua [Ivan Franko National University, Department of Metal Physics, 8 Kyrylo and Mephodiy Street, 79005 Lviv (Ukraine); Sklyarchuk, V. [Ivan Franko National University, Department of Metal Physics, 8 Kyrylo and Mephodiy Street, 79005 Lviv (Ukraine); Omelchuk, A.; Faidiuk, N.; Savchuk, R. [V.I. Vernadsky Institute of General and Inorganic Chemistry, 32/34 prosp. Akad. Palladina, 03680 Kyiv (Ukraine); Shtablavyy, I.; Vus, V. [Ivan Franko National University, Department of Metal Physics, 8 Kyrylo and Mephodiy Street, 79005 Lviv (Ukraine); Yakymovych, A. [Department of Inorganic Chemistry (Materials Chemistry), University of Vienna, Währinger Str. 42, A-1090 Vienna (Austria)

2014-04-01

Highlights: • Molten NaF–LiF–NdF{sub 3} eutectic and peritectic alloys can be used in liquid salt reactors. • A stepped dissociation exists well above melting in the both alloys. • Anomalous properties behaviour proves that a short-range order persists after melting. • Transformation of structure spread to a wide temperature range in the liquid phase. - Abstract: Experimental studies of viscosity, thermoelectric power and electrical conductivity of the ionic liquid alloys NaF–LiF–NdF{sub 3} were carried out in the wide temperature intervals above the melting points. Similar temperature dependences of these properties for different melt compositions have been revealed. The alloy composition has a significant influence on the interval of melt homogeneity and behaviour of the thermoelectric power temperature coefficient. It was found that a small shift from the peritectic to eutectic composition increases considerable the viscosity. A correlation between the structure and thermophysical properties has been analyzed. The results can be used in modelling a blanket for the liquid salt reactor.

Microstructure and Mechanical Properties of Mg-11Li-6Zn-0.6Zr-0.4Ag-0.2Ca-x Y Alloys.

Science.gov (United States)

Kim, Yong-Ho; Yoo, Hyo-Sang; Son, Hyeon-Taek

2018-09-01

Magnesium and its alloys are potential candidates for many automotive and aerospace applications due to their low density and high specific strength. However, the use of magnesium as wrought products is limited because of its poor workability at ambient temperatures. Mg-Li alloys containing 5-11 wt.% Li exhibit a two-phase structure consisting of a α (hcp) Mg-rich phase and a β (bcc) Li-rich phase. Mg-Li alloys with Li content greater than 11 wt.% exhibit a single-phase structure consisting of only the β phase. In the present study, we studied the effects of Y addition on the microstructure and mechanical properties of Mg-11Li-6Zn-0.6Zr-0.4Ag-0.2Ca based alloys. The melt was maintained at 720 °C for 20 min and poured into a mold. Then, the as-cast Mg alloys were homogenized at 350 °C for 4 h and were hot-extruded onto a 4-mm-thick plate with a reduction ratio of 14:1. The as-cast Mg-11Li-6Zn-0.6Zr-0.4Ag-0.2Ca-xY (x 0, 1, 3, and 5 wt.%) alloys were composed of α-Mg, β-Li, γ-Mg2Zn3Li, I-Mg3YZn6, W-Mg3Y2Zn3, and X-Mg12YZn phases. By increasing the Y content from 0 to 5 wt.%, the composition of the W-Mg3Y2Zn3 phase increased. With increasing Y content, from 0 to 1, 3, and 5 wt.%, the average grain size and ultimate tensile of the as-extruded Mg alloys decreased slightly, from 8.4, to 3.62, 3.56, and 3.44 μm and from 228.92 to 215.57, 187.47, and 161.04 MPa, respectively, at room temperature.

cap alpha. -transfer reactions /sup 27/Al(/sup 6/Li, d)/sup 31/P, /sup 29/Si(/sup 6/Li, d)/sup 33/S and /sup 31/P(/sup 6/Li, d)/sup 35/Cl at 36 MeV. [Angular distributions, EFR DWBA, spectroscopic strengths

Energy Technology Data Exchange (ETDEWEB)

Eswaran, M A; Gove, H E; Cook, R; Sikora, B [Rochester Univ., NY (USA). Nuclear Structure Research Lab.

1979-08-13

The ..cap alpha..-transfer reactions /sup 27/Al(/sup 6/Li,d)/sup 31/P,/sup 29/Si(/sup 6/Li,d) /sup 33/S and /sup 31/P(Li,d)/sup 35/Cl have been studied at a /sup 6/Li energy of 36 MeV. Absolute cross sections and angular distributions have been measured and an exact finite-range distorted-wave Born approximation analysis assuming a direct cluster transfer has been used to extract from the data ..cap alpha..-particle spectroscopic strengths for levels populated in /sup 31/P, /sup 33/S and /sup 35/Cl in three reactions respectively. The results show that in the case of most of the low-lying excited states of /sup 31/P a single value of L of the transferred ..cap alpha..-particle contributes, though a multiplicity of L-values are allowed by angular momentum selection rules. It is also found that the ..cap alpha..-particle spectroscopic strength of the ground state of /sup 31/P is a factor of 2 more than the strengths of the ground states of /sup 33/S and /sup 35/Cl. The ..cap alpha..-spectroscopic strengths of ground states of these, as well as other odd-A s-d shell nuclei, are compared with the presently available shell model calculations.

Relevance of LiPF6 as Etching Agent of LiMnPO4 Colloidal Nanocrystals for High Rate Performing Li-ion Battery Cathodes.

Science.gov (United States)

Chen, Lin; Dilena, Enrico; Paolella, Andrea; Bertoni, Giovanni; Ansaldo, Alberto; Colombo, Massimo; Marras, Sergio; Scrosati, Bruno; Manna, Liberato; Monaco, Simone

2016-02-17

LiMnPO4 is an attractive cathode material for the next-generation high power Li-ion batteries, due to its high theoretical specific capacity (170 mA h g(-1)) and working voltage (4.1 V vs Li(+)/Li). However, two main drawbacks prevent the practical use of LiMnPO4: its low electronic conductivity and the limited lithium diffusion rate, which are responsible for the poor rate capability of the cathode. The electronic resistance is usually lowered by coating the particles with carbon, while the use of nanosize particles can alleviate the issues associated with poor ionic conductivity. It is therefore of primary importance to develop a synthetic route to LiMnPO4 nanocrystals (NCs) with controlled size and coated with a highly conductive carbon layer. We report here an effective surface etching process (using LiPF6) on colloidally synthesized LiMnPO4 NCs that makes the NCs dispersible in the aqueous glucose solution used as carbon source for the carbon coating step. Also, it is likely that the improved exposure of the NC surface to glucose facilitates the formation of a conductive carbon layer that is in intimate contact with the inorganic core, resulting in a high electronic conductivity of the electrode, as observed by us. The carbon coated etched LiMnPO4-based electrode exhibited a specific capacity of 118 mA h g(-1) at 1C, with a stable cycling performance and a capacity retention of 92% after 120 cycles at different C-rates. The delivered capacities were higher than those of electrodes based on not etched carbon coated NCs, which never exceeded 30 mA h g(-1). The rate capability here reported for the carbon coated etched LiMnPO4 nanocrystals represents an important result, taking into account that in the electrode formulation 80% wt is made of the active material and the adopted charge protocol is based on reasonable fast charge times.

Band gap modification and ferroelectric properties of Bi{sub 0.5}(Na,K){sub 0.5}TiO{sub 3}-based by Li substitution

Energy Technology Data Exchange (ETDEWEB)

Quan, Ngo Duc [Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet road, Ha Noi (Viet Nam); International Training Institute for Materials Science, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hanoi (Viet Nam); Hung, Vu Ngoc [International Training Institute for Materials Science, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hanoi (Viet Nam); Quyet, Nguyen Van [Hanautech Co., Ltd., 832, Tamnip-dong, Yuseong-gu, Daejeon (Korea, Republic of); Chung, Hoang Vu [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet street, Hanoi (Viet Nam); Dung, Dang Duc, E-mail: dung.dangduc@hust.edu.vn [Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet road, Ha Noi (Viet Nam)

2014-01-15

We report on the reduction of band gap in Bi{sub 0.5}(Na{sub 0.82-x}Li{sub x}K{sub 0.18}){sub 0.5}(Ti{sub 0.95}Sn{sub 0.05})O{sub 3} from 2.99 eV to 2.84 eV due to the substitutions of Li{sup +} ions to Na{sup +} sites. In addition, the lithium substitution samples exhibit an increasing of the maximal polarizations from 21.8 to 25.7 μC/cm{sup 2}. The polarization enhancement of ferroelectric and reduction of the band gaps are strongly related to the Li substitution concentration as evaluated via the electronegative between A-site and oxygen and tolerance factor. The results are promising for photovoltaic and photocatalytic applications.

LiCaAlF sub 6 :Ce crystal: a new scintillator

CERN Document Server

Gektin, A V; Neicheva, S; Gavrilyuk, V; Bensalah, A; Fukuda, T; Shimamura, K

2002-01-01

Scintillation properties of LiCaAlF sub 6 :Ce crystal, well known as the effective UV laser material, is reported. Ce sup 3 sup + emission at 286-305 nm with a single exponential decay time of 35 ns provides a scintillation pulse. Radiation damage in pure and Ce-doped crystals is studied. In contrast to the majority of fluoride crystals, cerium is responsible for the ultradeep traps formation revealing thermostimulated luminescence. Overlapping of color center absorption and Ce sup 3 sup + ion emission bands limits the scintillation efficiency of LiCaAlF sub 6 :Ce at high radiation doses.

Estudo dos efeitos do LiNO3 na reação Álcali-Sílica e comparação com os efeitos da cinza volante na reação

Directory of Open Access Journals (Sweden)

D. J. F. Silva

Full Text Available Várias pesquisas realizadas com compostos a base de lítio tem mostrado resultados satisfatórios na redução da expansão associada à reação álcali-sílica (RAS, mas ainda existem muitas dúvidas sobre seus mecanismos de ação. A presente pesquisa avaliou os efeitos de uma adição química a base de nitrato de lítio (LiNO 3, utilizando várias dosagens, com o objetivo de entender seus mecanismos de ação sobre a expansão associada a RAS. O estudo dos efeitos do LiNO3 na RAS foi feito pelo método acelerado das barras de argamassa (ASTM C-1260, utilizando dois tipos de agregado reativo, levando o ensaio até 30 dias. Foram moldadas também barras de argamassa com uma adição mineral a base de cinza volante com o objetivo de comparar os efeitos de uma adição mineral com uma química na expansão devido a RAS. Os resultados do en- saio da ASTM C-1260 indicaram que as adições de lítio foram efetivas na redução da expansão, mas apresentaram valores de adição diferentes para o limite aceitável de 0.10% aos 14 dias para cada tipo de agregado. Foi observado também que as misturas contendo LiNO3 reduziram a expansão ao longo dos 30 dias, enquanto nas misturas contendo cinza volante a expansão continuou a aumentar ao longo do teste. O ensaio indicou que as dosagens de adição do lítio (Li2O/Na2Oeq eficazes na redução da expansão foram muito elevado em relação aos encontrados na literatura, mostrando que segundo Folliard et al. (2003, o uso de cimento com elevado teor de álcalis (Na2Oeq= 0.9 ± 1.0% e a modificação da ASTM C-1260, seria a melhor solução para obter valores de adição de lítio compatíveis com o de uso em campo.

Band gap modification and ferroelectric properties of Bi0.5(Na,K0.5TiO3-based by Li substitution

Directory of Open Access Journals (Sweden)

Ngo Duc Quan

2014-01-01

Full Text Available We report on the reduction of band gap in Bi0.5(Na0.82-xLixK0.180.5(Ti0.95Sn0.05O3 from 2.99 eV to 2.84 eV due to the substitutions of Li+ ions to Na+ sites. In addition, the lithium substitution samples exhibit an increasing of the maximal polarizations from 21.8 to 25.7 μC/cm2. The polarization enhancement of ferroelectric and reduction of the band gaps are strongly related to the Li substitution concentration as evaluated via the electronegative between A-site and oxygen and tolerance factor. The results are promising for photovoltaic and photocatalytic applications.

Reaction cross section measurements for the production of /sup 6/He(805 ms) and /sup 6/Li(175 ms) with 14. 7 Mev neutrons

Energy Technology Data Exchange (ETDEWEB)

Garg, K C; Khurana, C S [Punjabi Univ., Patiala (India). Dept. of Physics

1979-01-01

The automatic electronic programmer developed to handle the millisecond isomers has been utilized to measure the reaction cross-sections for the production of /sup 6/He from sup(7,6)Li((n,d)+(n,p))/sup 6/He and /sup 9/Be(n,..cap alpha..)/sup 6/He reactions and /sup 9/Li from /sup 9/Be(n,p)/sup 9/Li reaction. An on-line gated G.M. counter has been used to follow the decay curves of beta-activities of /sup 6/He(805 ms.) and /sup 9/Li(175 ms.) produced in the reactions. Values of measured cross sections are 10.4 +- 1.0 mb., 10.6 +- 1.1 mb. and 40.3 +- 4.0 mb respectively for the above the three reactions.

Effect of growth in lithium on ouabain binding, Na-K-ATPase and Na and K transport in hela cells.

Science.gov (United States)

Boardman, L J; Hume, S P; Lamb, J F; Polson, J

1975-01-01

1. HeLa cells were grown for 24 hr in growth medium in which part of the Na was replaced with Li. Ion contents, cell volumes and numbers, Na-K-ATPase and specific ouabain binding were measured. In some experiments the Na efflux and net Na transport was also measured. 2. Growth in Li caused a rise in the specific ouabain binding and membrane Na-K-ATPase of these cells. The Li concentrations in the cells necessary to produce this effect ranged up to 50 mM. 3. It is suggested that Li, like Na, acts on the genetic material of the cells to cause the production of more Na pumps within the membrane. PMID:124350

Much improved capacity and cycling performance of LiVMoO6 cathode for lithium ion batteries

International Nuclear Information System (INIS)

Zhou Liqun; Liang Yongguang; Hu Ling; Han Xiaoyan; Yi Zonghui; Sun Jutang; Yang Shuijin

2008-01-01

Spherical LiVMoO 6 nanocrystals as cathode for lithium ion batteries were synthesized using a solvothermal reaction method. Powder XRD data indicate that a single phase LiVMoO 6 with brannerite-type structure is obtained at 550 deg. C by the thermal treatment of the precursor for 6 h. SEM image shows that the particles are composed of loosely stacked spheres with a uniform particle size about 40 nm. The electrode properties of LiVMoO 6 have also been studied by galvanostatic cycling and ac impedance spectroscopy. LiVMoO 6 nanospheres delivered 172 mAh g -1 capacity in the initial discharge process with a reversible capacity retention of 94.4% after 100 cycles in the range of 3.6-1.80 V versus metallic Li at a current density of 100 mA g -1 . The microstructure developed in the electrodes give evidence that the particle size and morphological properties play an important role in the much improved capacity and cycling stability at large currents than ordinary samples

Nuclear reactions of the system 6 Li on 58 Ni near the Coulomb barrier

International Nuclear Information System (INIS)

Lizcano, D.; Aguilera, E.F.; Garcia M, H.; Martinez Q, E.

2004-01-01

Protons, alpha particles and deuterons coming from the reactions 6 Li + 58 Ni are detected to three different energy around the Coulomb barrier. The possible effects of the weakly bound character of the projectile are studied and the results are compared with previous data for the system 6 Li + 59 Co. (Author)

Parsec-scale Variations in the "7Li i/"6Li i Isotope Ratio Toward IC 348 and the Perseus OB 2 Association

International Nuclear Information System (INIS)

Knauth, D. C.; Taylor, C. J.; Federman, S. R.; Ritchey, A. M.; Lambert, D. L.

2017-01-01

Measurements of the lithium isotopic ratio in the diffuse interstellar medium from high-resolution spectra of the Li i λ 6708 resonance doublet have now been reported for a number of lines of sight. The majority of the results for the "7Li/"6Li ratio are similar to the solar system ratio of 12.2, but the line of sight toward o Per, a star near the star-forming region IC 348, gave a ratio of about two, the expected value for gas exposed to spallation and fusion reactions driven by cosmic rays. To examine the association of IC 348 with cosmic rays more closely, we measured the lithium isotopic ratio for lines of sight to three stars within a few parsecs of o Per. One star, HD 281159, has "7Li/"6Li ≃ 2 confirming production by cosmic rays. The lithium isotopic ratio toward o Per and HD 281159 together with published analyses of the chemistry of interstellar diatomic molecules suggest that the superbubble surrounding IC 348 is the source of the cosmic rays.

Study on lithium extraction from brines based on LiMn2O4/Li1-xMn2O4 by electrochemical method

International Nuclear Information System (INIS)

Zhao, Meng-Yao; Ji, Zhi-Yong; Zhang, Yong-Guang; Guo, Zhi-Yuan; Zhao, Ying-Ying; Liu, Jie; Yuan, Jun-Sheng

2017-01-01

Highlights: •A recovery system with LiMn 2 O 4 /Li 1-x Mn 2 O 4 as electrodes was used to extract lithium. •The influence sequence of coexisting ions on lithium extraction was Mg 2+ > Na + > Ca 2+ > K + . •The values of α Li-Na , α Li-Mg and α Li-Ca were more than 300, 70 and 110, respectively. •The specific energy consumption was between 18 and 19 W h·mol −1 . -- Abstract: Lithium rechargeable batteries have been used for lithium extraction in recent years. Here, we report on a highly selective lithium recovery system that consists of a LiMn 2 O 4 positive electrode, a Li 1-x Mn 2 O 4 negative electrode and a monovalent selective anion-exchange membrane. The effect of potential, temperature and coexisting ions on lithium extraction were investigated in this paper, and the lithium recovery system was applied to extract lithium from brine and concentrated seawater. The extraction capacity of Li + reached 34.31 mg· (1 g LiMn 2 O 4 ) −1 at 1.2 V. With higher reaction rate and lower energy consumption, 25 °C (room temperature) was considered as the appropriate temperature. The system still remained high selective for Li + even in the presence of impurity ions (K + , Na + , Mg 2+ , Ca 2+ ). With simulated brine and concentrated seawater as source solutions, the concentrations of Na + , Mg 2+ and Ca 2+ were reduced more than 300, 70 and 100 times, consuming 18–19 W h per mole of lithium recovered. And the electrodes still had high separation coefficients of Li + and Me n+ (Na + , Mg 2+ , Ca 2+ ) after five cycles although a slight drop was existing.

Magnetic signature of charge ordering in Li[Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 and Li sub 0 sub . sub 2 [Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4

CERN Document Server

Verhoeven, V W J; Mulder, F M

2002-01-01

The stoichiometric compound LiMn sub 2 O sub 4 is known to show charge ordering with well-defined Mn sup 3 sup + and Mn sup 4 sup + sites just below room temperature (RT). Above RT the electrons are hopping rapidly between sites. For lithium-ion batteries the material Li[Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 is technologically relevant. Due to the small amount of Li on the Mn site, the low-T regular ordering of the Mn charge appears to be destroyed completely, as is evidenced by neutron diffraction in the magnetically ordered state. However, the charges are still fixed in an irregular fashion, as can also be deduced from sup 7 Li nuclear magnetic resonance measurements. In the lithium-extracted compound Li sub 0 sub . sub 2 [Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 , predominantly Mn sup 4 sup + is present. Neutron diffraction in the magnetically ordered state shows a well-defined antiferromagnetic ordering, with doubling of the unit cell in three directions. Clear...

Experimental research of plastic scintillation detector loaded 6Li neutron energy response

International Nuclear Information System (INIS)

Wang Lizong; Zhang Chuanfei; Peng Taiping; Guo Cun; Yang Hongqiong; Zhang Jianhua

2005-01-01

A new plastic scintillator, plastic scintillator loaded 6 Li, is brought forward and developed in this paper in order to increase low energy neutron sensitivity. Neutron sensitivity of several plastic scintillation detectors loaded 6 Li new developed in neutron energy range 0.2 MeV-5.0 MeV are calibrated by direct current at serial accelerator. Energy response curves of the detectors are obtained in this experiment. It is shown that this new plastic scintillation detector can increase low energy neutron sensitivity in experimental results. (authors)

Study of the nuclear continuum of 28Si after excitation by inelastic 6Li scattering

International Nuclear Information System (INIS)

Seegert, G.

1985-01-01

For the study of the direct reaction mechanisms which contribute in the inelastic 6 Li scattering to the nuclear continuum of 28 Si at the Karlsruhe Isochronous Cyclotron particle-particle coincidence experiments were performed at an incident 6 Li energy of 156 MeV. Thereby the inelastically scattered 6 Li ions were measured in Si semiconductor telescopes under an angle of THETA=11 0 respectively 10 0 , while the coincident charged particles, mainly α particles with an energy of 70 MeV and protons with an energy up to 50 MeV could be detected in an angular range of -85 0 0 and three angles beyond the reaction plane. For a limited angular range simultaneously the α and 3 He fragments produced by the breakup of the 6 Li particle were taken up in coincidence with all light charged particles. (orig./HSI) [de

Response distributions of 6LiF and 7LiF thermoluminescence dosimeters in lithium blanket assemblies

International Nuclear Information System (INIS)

Maekawa, Hiroshi; Kusano, Jyo-ichi; Seki, Yasushi

1976-11-01

Measurement of the radiation-heating rate distribution in the fusion blanket is as important as measurement of the fission-rate distribution in a fission reactor. To obtain the information of radiation heating, the response (integral glow value) distributions in pseudo-spherical lithium assemblies with and without a graphite reflector were measured with 6 LiF and 7 LiF TLD's. The measured responses are normalized to values per source neutron. Experimental error is about 35%, and the error in positions of TLD's is about +- 3 mm. The experimental results are compared with those of calculation using RADHEAT code system and ENDF/B-III data file. (auth.)

Fusion cross sections for 6,7Li + 24Mg at energies around the barrier

International Nuclear Information System (INIS)

Ray, Maitreyi; Pradhan, M.K.; Kshetri, R.; Mukherjee, A.; Saha Sarkar, M.; Biswas, M.; Roy, S.; Basu, P.; Majumdar, H.; Dasmahapatra, B.; Sinha, M.; Palit, R.; Mazumdar, I.; Joshi, P.K.; Jain, H.C.

2006-01-01

The 6,7 Li + 24 Mg reactions in the energy interval E lab = 11-32 MeV using 6,7 Li beams have been investigated from the 14 UD BARC-TIFR Pelletron accelerator at TIFR, Mumbai. The γ-ray cross sections were measured using a Compton suppressed clover detector, placed at 55 deg with respect to the beam direction

Trinucleon cluster knockout from 6Li

International Nuclear Information System (INIS)

Connelly, J.P.; Berman, B.L.; Briscoe, W.J.; Dhuga, K.S.; Mokhtari, A.; Zubanov, D.; Blok, H.P.; Ent, R.; Mitchell, J.H.; Lapikas, L.

1998-01-01

The momentum-transfer dependence of the 3 H and 3 He knockout reactions from 6 Li via exclusive electron scattering has been measured, and the two reactions are compared. In the absence of two-step processes, the ratio of the fivefold cross sections for these mirror reactions should simply scale by the ratio of the 3 H and 3 He electron-scattering cross sections. A significant deviation from this simple expectation is seen at low momentum transfer. Possible explanations for this dramatic difference in cross sections for these mirror reactions are discussed. copyright 1998 The American Physical Society

6Li real potential volume integrals in elastic scattering and distorted-waveBorn approximation analyses

International Nuclear Information System (INIS)

Lezoch, P.; Trost, H.; Strohbusch, U.

1981-01-01

The magnitudes of volume integrals per interacting nucleon pair J/sub R/' calculated from a compilation of 6 Li potentials vary between 100 and 500 MeV fm 3 . They are grouped in discrete branches with J/sub R/(A) smoothly increasing with decreasing target mass. Comparison with the results for lighter projectiles restricts the ''physically meaningful'' branches to those characterized by J/sub R/ (A> or =48) 3 . ( 6 Li,d) reaction analyses yield the same fit qualities for 6 Li potentials of the different discrete families, but deduced spectroscopic factors jump (by factors of approx.3) when changing between successive families

Na insertion into nanocrystalline Li4Ti5O12 spinel: An electrochemical study

Czech Academy of Sciences Publication Activity Database

Zukalová, Markéta; Pitňa Lásková, Barbora; Klementová, Mariana; Kavan, Ladislav

2017-01-01

Roč. 245, AUG 2017 (2017), s. 505-511 ISSN 0013-4686 R&D Projects: GA ČR GA15-06511S; GA MŠk LM2015087 Institutional support: RVO:61388955 ; RVO:68378271 Keywords : Na insertion * Li4Ti5O12 * nanocrystalline Subject RIV: CG - Electrochemistry; BM - Solid Matter Physics ; Magnetism (FZU-D) OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis); Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D) Impact factor: 4.798, year: 2016

Ab initio investigations of the electronic structures and chemical bonding in LiCo{sub 6}P{sub 4} and Li{sub 2}Co{sub 12}P{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Matar, Samir F. [CNRS, ICMCB, UPR 9048, F‐33600 Pessac (France); Université de Bordeaux, ICMCB, UPR 9048, F‐33600 Pessac (France); Al-Alam, Adel; Ouaini, Naïm [Université Saint-Esprit de Kaslik (USEK), Groupe OCM (Optimization et Caractérisation des Matériaux), CSR-USEK, CNRS-L, Jounieh (Lebanon); Pöttgen, Rainer, E-mail: pottgen@uni-muenster.de [Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstraße 30, D-48149 Münster (Germany)

2013-06-15

The electronic structures of the metal-rich phosphides LiCo{sub 6}P{sub 4} and Li{sub 2}Co{sub 12}P{sub 7} were studied by DFT calculations. Both phosphides consist of three-dimensional [Co{sub 6}P{sub 4}] and [Co{sub 12}P{sub 7}] polyanionic networks which leave hexagonal channels for the lithium atoms. COOP data show strong Co–P and Co–Co bonding within the polyanions. The lithium atoms have trigonal prismatic phosphorus coordination. Total energy calculations indicate stability upon de-lithiation towards the Co{sub 6}P{sub 4} and Co{sub 12}P{sub 7} substructures - Graphical abstract: The cobalt–phosphorus networks in LiCo{sub 6}P{sub 4} and Li{sub 2}Co{sub 12}P{sub 7}. - Highlights: • Chemical bonding resolved in the metal-rich phosphides LiCo{sub 6}P{sub 4} and Li{sub 2}Co{sub 12}P{sub 7}. • Strong covalent Co–P bonding character in the [Co{sub 6}P{sub 4}] and [Co{sub 12}P{sub 7}] substructures. • Total energy calculations indicate stability of the de-lithiated substructures.

Improved Cycling Stability of Cobalt-free Li-rich Oxides with a Stable Interface by Dual Doping

International Nuclear Information System (INIS)

Xie, Dongjiu; Li, Guangshe; Li, Qi; Fu, Chaochao; Fan, Jianming; Li, Liping

2016-01-01

Highlights: • Cobalt-free Na_xLi_1_._2_-_xMn_0_._6_-_xAl_xNi_0_._2O_2 oxides are prepared by a sol-gel method. • Dual-doping strengthens the covalence of Mn-O bonds and suppresses the side reactions between cathode and electrolyte. • Doped cathode has a capacity retention over 92.2% after 100 cycles at a high temperature of 55 °C. - Abstract: Li-rich cobalt-free oxides, popularly used as a cathode with high capacity in lithium ion battery, always suffer from poor cycling stability between 2.0 and 4.8 V vs Li"+/Li, especially when cycled at high temperatures (>50 °C). To overcome this issue, Na"+ and Al"3"+ dual-doped Na_xLi_1_._2_-_xMn_0_._6_-_xAl_xNi_0_._2O_2 Li-rich cathode is prepared in this study. It is shown that the side reactions between cathode and electrolyte during cycling are suppressed. The improved cycling performance is observed for all of the doped samples, among which the sample with x = 0.03 exhibits the highest capacity retention of 86.1% after 200 cycles between 2.0 and 4.8 V at 2C (1C = 200 mA g"−"1) and shows a remarkable cycling stability, even at a high temperature of 55 °C (a capacity retention of 92.2% after 100 cycles). Moreover, the average voltage of the sample with x = 0.03 after 100 cycles at 0.5C remains at 3.11 V with a retention ratio of 86.6%. This work provides a new strategy to develop Li-rich cobalt-free cathodes with excellent cycling stability for lithium ion batteries at high temperatures.

Quaternary system LiF-LiCl-LiVO3-Li2MoO4

International Nuclear Information System (INIS)

Anipchenko, B.V.; Garkushin, I.K.

2000-01-01

Interactions in the LiF-LiCl-LiVO 3 -Li 2 MoO 4 system are studied by differential thermal analysis. Rate of heating/cooling of the samples comprised 15 Grad/min, mass of sample composed 0.2 g. The system was investigated in the 300-650 Deg C range. X-ray diffraction method was used for determination of purity of the reagents. Composition and temperature of quaternary component eutectics are determined: 16.5 mol. % of LiF, 47.0 mol. % of LiCl, 28.8 mol. % of LiVO 3 , 7.6 mol. % of Li 2 MoO 4 ; 387 Deg C. Mean value of melting enthalpy of quaternary eutectics mixture in the LiF-LiCl-LiVO 3 -Li 2 MoO 4 system on the results of the tests was in the range of 222 kJ/kg [ru

Production of 232,233Pa in 6Li+232Th Collisions in the Classical Trajectory Approach

International Nuclear Information System (INIS)

Aleshin, V.P.

2000-01-01

The semiclassical model of nuclear reactions with loosely bound projectiles (V.P. Aleshin, B.I. Sidorenko, Acta Phys. Pol. B29, 325 (1998)) is refined and compared with experimental data of Rama Rao et al. on the excitation function for the production of 232,233 Pa in 6 Li+ 232 Th collisions at E = 30-50 MeV. The main contribution to the production of 232 Pa is the 2 neutron emission from excited states of 234 Pa formed in the ( 6 Li,α) reaction. The main source of 233 Pa is the ( 6 Li,αp) reaction followed by γ transitions from excited states of 233 Th to 233 Th (g.s.) which transforms to 233 Pa through β - decay. The ground state of 6 Li regarded as a combination of n+p+α is modeled with the K=2, l x =l y =0 hyperspherical function. The calculation underpredicts the excitation function of 232 Pa by a factor of 0.6 and overpredicts the excitation function of 233 Pa by a factor of 2.3, on the average. With the more realistic wave function of 6 Li both factors are expected to be closer to 1. (author)

Thermodynamic assessment of EuBr2 unary and LiBr-EuBr2 and NaBr-EuBr2 binary systems

International Nuclear Information System (INIS)

Gong, Weiping; Gaune-Escard, Marcelle

2009-01-01

As a basis for the design and development of molten salt mixtures, thermodynamic calculations of the phase diagrams and thermodynamic properties were carried out on the EuBr 2 unary and LiBr-EuBr 2 and NaBr-EuBr 2 binary systems over a wide temperature and composition range, respectively. The Gibbs energy of EuBr 2 was evaluated using an independent polynomial to fit the experimental heat capacity, the thermodynamic parameters for each phase in the LiBr-EuBr 2 and NaBr-EuBr 2 systems were optimized by using available experimental information on phase diagrams. A regular substitutional solution model for the liquid phase and Neumann-Kopp rule for the stoichiometric compound LiEu 2 Br 5 were adopted to reproduce the experimental data with reasonable excess Gibbs energy. Comparisons between the calculated phase diagrams and thermodynamic quantities show that all reliable experimental information is satisfactorily accounted for by the present thermodynamic description. Some thermodynamic properties were predicted to check the suitability of the present calculation.

Sodium storage capability of spinel Li4Mn5O12

International Nuclear Information System (INIS)

Zhang, Jiaolong; Wang, Wenhui; Li, Yingshun; Yu, Denis Y.W.

2015-01-01

Highlights: • Electrochemical behavior of spinel Li 4 Mn 5 O 12 is examined in Na-ion battery. • A capacity of 120.7 mAh g −1 is obtained during the first sodiation process. • Na storage performance is found to be strongly dependent on particle size. • Ion-exchange between Li ions and Na ions occurs in Li 4 Mn 5 O 12 structure upon cycling. • Loss of crystallinity with cycling, leading to capacity fading. - Abstract: Spinel Li 4 Mn 5 O 12 , a well-known 3 V Li-ion battery (LIB) material with excellent cycling stability and good rate capability, is examined as Na-ion battery (NIB) cathode for the first time. Electrochemical studies clearly show that Na ions can be reversibly inserted into and extracted from the three-dimensional spinel structure. However, unlike in LIB, the available capacity in NIB is strongly dependent on the particle size and current rate due to the sluggish Na-ion transport in solid phase. Cycle performance of Li 4 Mn 5 O 12 in NIB is also inferior to that in LIB. Ex-situ X-ray diffraction study indicates a gradual loss of crystallinity with cycling, and that the crystal lattice undergoes an irreversible expansion during the initial 20 cycles. Inductively coupled plasma spectroscopy shows a decrease of Li/Mn ratio in Li 4 Mn 5 O 12 with cycling. The results suggest that Li ions are removed from the material during the charging process. The charge-discharge mechanism is also discussed in the paper.

Importance of $1n$-stripping process in the $^{6}$Li+$^{159}$Tb reaction

OpenAIRE

Pradhan, M. K.; Mukherjee, A.; Roy, Subinit; Basu, P.; Goswami, A.; Kshetri, R.; Palit, R.; Parkar, V. V.; Ray, M.; Sarkar, M. Saha; Santra, S.

2013-01-01

The inclusive cross sections of the $\\alpha$-particles produced in the reaction $^{6}$Li+$^{159}$Tb have been measured at energies around the Coulomb barrier. The measured cross sections are found to be orders of magnitude larger than the calculated cross sections of $^{6}$Li breaking into $\\alpha$ and $d$ fragments, thus indicating contributions from other processes. The experimental cross sections of $1n$-stripping and $1n$-pickup processes have been determined from an entirely different me...

Crystal Structure of Na3MoCl6

Directory of Open Access Journals (Sweden)

Martin Beran

2011-07-01

Full Text Available The ternary chloride Na3MoCl6 is obtained as red crystals from a disproportionation reaction of molybdenum dichloride, {Mo6}Cl12, in an acidic NaCl/AlCl3 melt at 350 °C. The crystal structure (trigonal, P-31c, a = 687.1(1, c = 1225.3(2 pm, Z = 2, V = 501,0(1 106 pm3 is that of Na3CrCl6: within a hexagonal closest-packing of chloride ions two thirds of the octahedral voids are filled between the AB double layers with Na+/Mo3+, and between the BA layers with Na+.

Resonances in the proton-6Li scattering

International Nuclear Information System (INIS)

Haller, M.

1986-01-01

The differential cross section and the analyzing power of the p+ 6 Li scattering were measured in the laboratory energy range from 1.6 respectively 2.8 MeV to 10 MeV at 45 respectively 40 energies in full angular distributions. The data were subjected both to an analysis in the optical model which yielded already hints to resonance effects and to a comphrehensive scattering-phase analysis for L=0, 1, and 2 under inclusion of channel spin and orbital angular momentum mixings. The consistent description of all data required the assumption of broad resonance structures. An approximate parametrization by a Breit-Wigner formula allowed the estimation of the resonance parameters. (orig./HSI) [de

Two-proton pickup studies with the (6Li,8B) reaction

International Nuclear Information System (INIS)

Weisenmiller, R.B.

1976-01-01

The ( 6 Li, 8 B) reaction has been investigated on targets of 26 Mg, 24 Mg, 16 O, 13 C, 12 C, 11 B, 10 B, and 9 Be at a bombarding energy of 80.0 MeV, and on targets of 16 O, 12 C, 9 Be, 7 Li, and 6 Li at a bombarding energy of 93.3 MeV. Only levels consistent with direct, single-step two-proton pickup reaction mechanisms were observed to be strongly populated. On T/sub z/ = 0 targets, the spectroscopic selectivity of this reaction resembles that of the analogous (p,t) reaction. Additionally, these data demonstrate the dominance of spatially symmetric transfer of the two protons. On T/sub z/ greater than 0 targets the ( 6 Li, 8 B) reaction was employed to locate two previously unreported levels (at 7.47 +- 0.05 MeV and 8.86 +- 0.07 MeV) in the T/sub z/ = 2 nuclide 24 Ne and to establish the low-lying 1p-shell states in the T/sub z/ = 3 / 2 nuclei 11 Be, 9 Li, and 7 He. However, no evidence was seen for any narrow levels in the T/sub z/ = 3 / 2 nuclide 5 H nor for any narrow excited states in 7 He. The angular distributions reported here are rather featureless and decrease monotonically with increasing angle. This behavior can be shown by a semi-classical reaction theory to be a consequence of the reaction kinematics. A semi-classical approach also suggests that the kinematic term in the transition matrix element is only weakly dependent upon the angular momentum transfer (which is consistent with simple Distorted Wave Born Approximation calculations). However, only qualitative agreement was obtained between the observed relative transition yields and semi-classical predictions, using the two-nucleon coefficients of fractional parentage of Cohen and Kurath, probably due to the limitations of the semi-classical reaction theory

Eu and Rb co-doped LiCaAlF6 scintillators for neutron detection

International Nuclear Information System (INIS)

Yamaji, Akihiro; Yanagida, Takayuki; Kawaguchi, Noriaki; Yokota, Yuui; Fujimoto, Yutaka; Kurosawa, Shunsuke; Pejchal, Jan; Watanabe, Kenichi; Yamazaki, Atsushi; Yoshikawa, Akira

2013-01-01

Eu and Rb co-doped LiCaAlF 6 (LiCAF) single crystals with different dopant concentrations were grown by the micro-pulling-down method for neutron detection. Their transmittance spectra showed strong absorption bands at 200–220 and 290–350 nm, and under 241 Am alpha-ray excitation, their radioluminescence spectra exhibited an intense emission peak at 373 nm that was attributed to the Eu 2+ 5d–4f transition. These results were consistent with those for the Rb-free Eu:LiCAF. The highest light yield among the grown crystals was 36,000 ph/n, which was 20% greater than that of the Rb-free crystal. In addition, the neutron-excited scintillation decay times were 650–750 ns slower than that of the Rb-free Eu:LiCAF. -- Highlights: •Eu and Rb co-doped LiCaAlF 6 crystals were grown by the micro-pulling down method. •Transmittance, photoluminescence and radioluminescence spectra were measured. •The light yields and scintillation decays were evaluated under 252 Cf neutron irradiation

The preparation and properties of a novel electrolyte of electrochemical double layer capacitors based on LiPF6 and acetamide

International Nuclear Information System (INIS)

Li Qi; Zuo Xiaoxi; Liu Jiansheng; Xiao Xin; Shu Dong; Nan Junmin

2011-01-01

A novel electrolyte applied in electrochemical double-layer capacitors (EDLCs) has been prepared based on lithium hexafluorophosphate (LiPF 6 ) and acetamide and subsequently characterized by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), electrochemical techniques and so on. The mixtures of LiPF 6 and acetamide at the molar ratios of 1:4 to 1:6 exist as liquids below 25 °C, which is attributed to the melting point depression of mixture and the coordination of the polar groups (C=O and NH groups) of acetamide with Li + and PF 6 − ions. The strong interaction between LiPF 6 and acetamide results in the rupture of the electrovalent bond of LiPF 6 and the breakage of hydrogen bonds among the acetamide molecules, leading to the formation of a liquid electrolyte. The LiPF 6 /acetamide electrolyte with a molar ratio of 1:5.5 exhibits a 5.2 V electrochemical window and suitable ionic conductivity at room temperature. In particular, the coin-type cells with carbon electrodes and LiPF 6 /acetamide electrolyte possess high thermal stability and electrochemical properties, showing that the as-prepared LiPF 6 /acetamide electrolyte is a promising candidate for EDLCs.

Synthesis and thin film growth of alkaline cobaltates Na{sub x}CoO{sub 2} and Li{sub x}CoO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, Sandra

2013-02-18

In this study sol-gel synthesis was used to fabricate Na{sub x}CoO{sub 2}, LiNi{sub 1/2}Co{sub 1/2}O{sub 2} and LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2}. By using acetate precursors a lower process temperature was accessible, which has a positive effect on the sodium and lithium loss during synthesis. The lithium based powders were single phase and kept cation stoichiometry after sintering. A small grain size is favourable for battery applications. Sodium content was slightly reduced after temperature treatment compared to the initial cation mixture, due to the high volatility of Na. To fabricate thin films PLD was used for deposition. All films were deposited on SrTiO{sub 3} substrates. The growth mechanism of Na{sub x}CoO{sub 2} on SrTiO{sub 3} was investigated and an in-plane and out-of-plane relation between film an substrate was found. The films grow 15 and 45 rotated with respect to the ab-plane of the substrate and grow in c-axis direction out-of-plane. The sodium content and the crystallinity of the Na{sub x}CoO{sub 2} was investigated as a function of the post deposition treatment. A change of x between 0.38 and 0.84 can be achieved. The γ-phase was preserved in all films despite of the change of the sodium content. The in-situ variation of sodium stoichiometry, allows to tune the film properties in a wide range. This feature is an advantage compared to bulk Na{sub x}CoO{sub 2}, in which only certain stoichiometries can be stabilized. Fabrication of superconducting thin films Na{sub 0.33}CoO{sub 2}.1.3H{sub 2}O was challenging, since the superconducting phase is metastable and hardly to stabilize as a thin film. LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} and LiNi{sub 1/2}Co{sub 1/2}O{sub 2} thin films were grown by PLD in (104)-orientation. These thin film materials are promising candidates as cathode materials for the development of thin film batteries.

Resistivity switching properties of Li-doped ZnO films deposited on LaB_6 electrode

International Nuclear Information System (INIS)

Igityan, A.; Kafadaryan, Y.; Aghamalyan, N.; Petrosyan, S.; Badalyan, G.; Vardanyan, V.; Nersisyan, M.; Hovsepyan, R.; Palagushkin, A.; Kryzhanovsky, B.

2015-01-01

Current–voltage (I–V) characteristics of Al/p-ZnO:Li/LaB_6 device, measured in voltage sweep mode, show unipolar resistive switching and monostable threshold switching (URS and MTS) for different bias voltage polarities. URS could be transformed to MTS by application of reverse bias voltage. With increasing number of cycles, URS is converted to bipolar resistive switching mode which is lost after certain number of cycles, and device turns into an ordinary resistor. Analysis of linear fitting I–V curves suggests that ohmic and space charge limited current laws are responsible for conductivity mechanism of Al/p-ZnO:Li/LaB_6 device. - Highlights: • Al/p-ZnO:Li/LaB_6 memristive device is fabricated using an e-beam evaporation technique. • Current–voltage (I–V) characteristics are studied. • Type of resistive switching mode depends on the bias voltage polarity and number of switching cycles. • Resistive switching in Al/ZnO:Li/LaB_6 has an interfacial effect. • Ohmic and SCLC laws are responsible for conductivity mechanism of resistive states.

Ferroelectric ferrimagnetic LiFe2F6 : Charge-ordering-mediated magnetoelectricity

Science.gov (United States)

Lin, Ling-Fang; Xu, Qiao-Ru; Zhang, Yang; Zhang, Jun-Jie; Liang, Yan-Ping; Dong, Shuai

2017-12-01

Trirutile-type LiFe2F6 is a charge-ordered material with an Fe2 +/Fe3 + configuration. Here, its physical properties, including magnetism, electronic structure, phase transition, and charge ordering, are studied theoretically. On one hand, the charge ordering leads to improper ferroelectricity with a large polarization. On the other hand, its magnetic ground state can be tuned from the antiferromagnetic to ferrimagnetic by moderate compressive strain. Thus, LiFe2F6 can be a rare multiferroic with both large magnetization and polarization. Most importantly, since the charge ordering is the common ingredient for both ferroelectricity and magnetization, the net magnetization may be fully switched by flipping the polarization, rendering intrinsically strong magnetoelectric effects and desirable functions.

α +d →6Li+γ astrophysical S factor and its implications for Big Bang nucleosynthesis

Science.gov (United States)

Grassi, A.; Mangano, G.; Marcucci, L. E.; Pisanti, O.

2017-10-01

The α +d →6Li +γ radiative capture is studied in order to predict the 6Li primordial abundance. Within a two-body framework, the α particle and the deuteron are considered the structureless constituents of 6Li. Five α +d potentials are used to solve the two-body problem: four of them are taken from the literature, only one having also a tensor component. A fifth model is here constructed in order to reproduce, besides the 6Li static properties as binding energy, magnetic dipole, and electric quadrupole moments, also the S -state asymptotic normalization coefficient (ANC). The two-body bound and scattering problem is solved with different techniques, in order to minimize the numerical uncertainty of the present results. The long-wavelength approximation is used, and therefore only the electric dipole and quadrupole operators are retained. The astrophysical S factor is found to be significantly sensitive to the ANC, but in all the cases in good agreement with the available experimental data. The theoretical uncertainty has been estimated of the order of few percent when the potentials which reproduce the ANC are considered, but increases up to ≃20 % when all five potential models are retained. The effect of this S -factor prediction on the 6Li primordial abundance is studied, using the public code PArthENoPE. For the five models considered here we find 6Li/H=(0.9 -1.8 ) ×10-14 , with the baryon density parameter in the 3-σ range of Planck 2015 analysis, Ωbh2=0.022 26 ±0.000 23 .

Measurement of the 2H(7Be, 6Li)3He reaction rate and its contribution to the primordial lithium abundance

Science.gov (United States)

Li, Er-Tao; Li, Zhi-Hong; Yan, Sheng-Quan; Su, Jun; Guo, Bing; Li, Yun-Ju; Wang, You-Bao; Lian, Gang; Zeng, Sheng; Chen, Si-Zhe; Ma, Shao-Bo; Li, Xiang-Qing; He, Cao; Sun, Hui-Bin; Liu, Wei-Ping

2018-04-01

In the standard Big Bang nucleosynthesis (SBBN) model, the lithium puzzle has attracted intense interest over the past few decades, but still has not been solved. Conventionally, the approach is to include more reactions flowing into or out of lithium, and study the potential effects of those reactions which were not previously considered. 7Be(d, 3He)6Li is a reaction that not only produces 6Li but also destroys 7Be, which decays to 7Li, thereby affecting 7Li indirectly. Therefore, this reaction could alleviate the lithium discrepancy if its reaction rate is sufficiently high. However, there is not much information available about the 7Be(d, 3He)6Li reaction rate. In this work, the angular distributions of the 7Be(d, 3He)6Li reaction are measured at the center of mass energies E cm = 4.0 MeV and 6.7 MeV with secondary 7Be beams for the first time. The excitation function of the 7Be(d, 3He)6Li reaction is first calculated with the computer code TALYS and then normalized to the experimental data, then its reaction rate is deduced. A SBBN network calculation is performed to investigate its influence on the 6Li and 7Li abundances. The results show that the 7Be(d, 3He)6Li reaction has a minimal effect on 6Li and 7Li because of its small reaction rate. Therefore, the 7Be(d, 3He)6Li reaction is ruled out by this experiment as a means of alleviating the lithium discrepancy. Supported by National Natural Science Foundation of China (11375269, 11505117, 11490560, 11475264, 11321064), Natural Science Foundation of Guangdong Province (2015A030310012), 973 program of China (2013CB834406) and National key Research and Development Province (2016YFA0400502)

Introducing a Hydrogen-Bond Donor into a Weakly Nucleophilic Brønsted Base: Alkali Metal Hexamethyldisilazides (MHMDS, M=Li, Na, K, Rb and Cs) with Ammonia.

Science.gov (United States)

Neufeld, Roman; Michel, Reent; Herbst-Irmer, Regine; Schöne, Ralf; Stalke, Dietmar

2016-08-22

Alkali metal 1,1,1,3,3,3-hexamethyldisilazide (MHMDSs) are one of the most utilised weakly nucleophilic Brønsted bases in synthetic chemistry and especially in natural product synthesis. Like lithium organics, they aggregate depending on the employed donor solvents. Thus, they show different reactivity and selectivity as a function of their aggregation and solvation state. To date, monomeric LiHMDS with monodentate donor bases was only characterised in solution. Since the first preparation of LiHMDS in 1959 by Wannagat and Niederprüm, all efforts to crystallise monomeric LiHMDS in the absence of chelating ligands failed. Herein, we present ammonia adducts of LiHMDS, NaHMDS, KHMDS, RbHMDS and CsHMDS with unprecedented aggregation motifs: 1) The hitherto missing monomeric key compound in the LiHMDS aggregation architectures. Monomeric crystal structures of trisolvated LiHMDS (1) and NaHMDS (2), showing unique intermolecular hydrogen bonds, 2) the unprecedented tetrasolvated KHMDS (3) and RbHMDS (4) dimers and 3) the disolvated CsHMDS (5) dimer with very close intermolecular Si-CH3 ⋅⋅⋅Cs s-block "agostic" interactions have been prepared and characterised by single-crystal X-ray structure analysis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Measurement of the cross section of the 8Li(d,α)6He reaction of possible relevance to big bang nucleosynthesis

International Nuclear Information System (INIS)

Sahin, L.; Boyd, R.N.; Cole, A.L.; Famiano, M.; Gueray, R.T.; Murphy, A. St.J.; Oezkan, N.; Kolata, J.J.; Guimaraes, V.; Hencheck, M.

2002-01-01

We report measurements of the cross section of the 8 Li(d,α) 6 He reaction in the energy range E c.m. =2.3-3.5 MeV using a 8 Li-radioactive beam on a CD 2 foil. The astrophysical S factor and reaction rate were calculated from the measured cross section. The 6 He nuclei produced in the reaction were detected in solid-state detector telescopes. This reaction might have affected the primordial abundance of 6 Li in big bang nucleosynthesis, since 6 He beta decays to 6 Li. However, several big bang nucleosynthesis network calculations were found to be insensitive to this reaction, suggesting that the 8 Li(d,α) 6 He reaction does not affect 6 Li primordial production

Effect of charge compensator ions (R+ = Li+, Na+ and K+) on Sr2MgSi2O7:Dy3+ phosphors by solid-state reaction method

Science.gov (United States)

Sahu, Ishwar Prasad

2016-09-01

The Sr2MgSi2O7:Dy3+ and Sr2MgSi2O7:Dy3+, R+ (R+ = Li+, Na+ and K+) phosphors were prepared by solid-state reaction method. The crystal structures of sintered phosphors were an akermanite-type structure which belongs to the tetragonal crystallography. The prepared phosphors were excited at 350 nm, and their corresponding emission spectrum were recorded at blue (482 nm) and yellow (575 nm) region due to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions, respectively, of Dy3+ ions. Commission Internationale de L'Eclairage coordinates have been calculated for each sample and its value exhibited that overall emission is near white light. The possible mechanisms of discussed white light emitting phosphors were also investigated. In order to investigate the suitability of the samples as white color light sources for industrial uses, color purity, correlated color temperature (CCT) and color rendering index (CRI) were calculated. Values of color purity, CCT and CRI were found well within the defined acceptable range. With incorporating (R+ = Li+, Na+ and K+) as charge compensator ions, the emission intensity of Sr2MgSi2O7:Dy3+ can be obviously enhanced. The results indicate that prepared phosphors may be a potential application in display devices.

Effect of charge compensator ions (R+ = Li+, Na+ and K+) on Sr2MgSi2O7:Dy3+ phosphors by solid-state reaction method

International Nuclear Information System (INIS)

Sahu, Ishwar Prasad

2016-01-01

The Sr 2 MgSi 2 O 7 :Dy 3+ and Sr 2 MgSi 2 O 7 :Dy 3+ , R + (R + = Li + , Na + and K + ) phosphors were prepared by solid-state reaction method. The crystal structures of sintered phosphors were an akermanite-type structure which belongs to the tetragonal crystallography. The prepared phosphors were excited at 350 nm, and their corresponding emission spectrum were recorded at blue (482 nm) and yellow (575 nm) region due to the 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 transitions, respectively, of Dy 3+ ions. Commission Internationale de L'Eclairage coordinates have been calculated for each sample and its value exhibited that overall emission is near white light. The possible mechanisms of discussed white light emitting phosphors were also investigated. In order to investigate the suitability of the samples as white color light sources for industrial uses, color purity, correlated color temperature (CCT) and color rendering index (CRI) were calculated. Values of color purity, CCT and CRI were found well within the defined acceptable range. With incorporating (R + = Li + , Na + and K + ) as charge compensator ions, the emission intensity of Sr 2 MgSi 2 O 7 :Dy 3+ can be obviously enhanced. The results indicate that prepared phosphors may be a potential application in display devices. (orig.)

Electrochemical studies on the redox behavior of zirconium in the LiF-NaF eutectic melt

Energy Technology Data Exchange (ETDEWEB)

Xu, Liang [School of Metallurgy, Northeastern University, Shenyang 110004 (China); Xiao, Yanping [School of Metallurgical Engineering, Anhui University of Technology, Ma' anshan 243002 (China); Zr-Hf-Ti Metallurgie B.V., Den Haag 2582 SB (Netherlands); Xu, Qian, E-mail: qianxu@shu.edu.cn [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Sandwijk, Anthonie van [Zr-Hf-Ti Metallurgie B.V., Den Haag 2582 SB (Netherlands); Zhao, Zhuo [School of Metallurgical Engineering, Anhui University of Technology, Ma' anshan 243002 (China); Song, Qiushi; Cai, Yanqing [School of Metallurgy, Northeastern University, Shenyang 110004 (China); Yang, Yongxiang [School of Metallurgical Engineering, Anhui University of Technology, Ma' anshan 243002 (China); Department of Materials Science and Engineering, Delft University of Technology, 2628 CD Delft (Netherlands)

2017-05-15

In the present paper, a detailed study of the redox behavior of zirconium in the eutectic LiF-NaF system was carried out on an inert molybdenum electrode at 750 °C. Several transient electrochemical methods were used such as cyclic voltammetry, square wave voltammetry, chronopotentiometry, and open circuit voltammetry. The reduction of Zr (IV) was found to follow a two-step mechanism of Zr (IV)/Zr (II) and Zr (II)/Zr at the potentials of about −1.10 and −1.50 V versus Pt, respectively. The theoretical evaluations of the number of transferred electrons according to both cyclic voltammetry and square wave voltammetry further confirmed the Zr reduction mechanism. The estimations of Zr (IV) diffusion coefficient in the LiF-NaF eutectic melt at 750 °C through cyclic voltammetry and chronopotentiometry are in fair agreement, as to be approximately 1.13E-5 and 2.42E-5 cm{sup 2}/s, respectively. - Highlights: •The redox mechanism of zirconium in a fluoride salt system was investigated. •A multi-step redox process of Zr was found with various electrochemical methods. •Perspectives on zirconium electro-refining process were proposed.

Parsec-scale Variations in the {sup 7}Li i/{sup 6}Li i Isotope Ratio Toward IC 348 and the Perseus OB 2 Association

Energy Technology Data Exchange (ETDEWEB)

Knauth, D. C. [Woodlawn High School, 1801 Woodlawn Drive, Baltimore, MD 21207 (United States); Taylor, C. J.; Federman, S. R. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Ritchey, A. M. [Department of Astronomy, University of Washington, Seattle, WA, 98195 (United States); Lambert, D. L., E-mail: knauth_dc2@hotmail.com, E-mail: steven.federman@utoledo.edu, E-mail: cjtaylor@astro.umd.edu, E-mail: aritchey@astro.washington.edu, E-mail: dll@astro.as.utexas.edu [Department of Astronomy, University of Texas, Austin, TX 78712 (United States)

2017-01-20

Measurements of the lithium isotopic ratio in the diffuse interstellar medium from high-resolution spectra of the Li i λ 6708 resonance doublet have now been reported for a number of lines of sight. The majority of the results for the {sup 7}Li/{sup 6}Li ratio are similar to the solar system ratio of 12.2, but the line of sight toward o Per, a star near the star-forming region IC 348, gave a ratio of about two, the expected value for gas exposed to spallation and fusion reactions driven by cosmic rays. To examine the association of IC 348 with cosmic rays more closely, we measured the lithium isotopic ratio for lines of sight to three stars within a few parsecs of o Per. One star, HD 281159, has {sup 7}Li/{sup 6}Li ≃ 2 confirming production by cosmic rays. The lithium isotopic ratio toward o Per and HD 281159 together with published analyses of the chemistry of interstellar diatomic molecules suggest that the superbubble surrounding IC 348 is the source of the cosmic rays.

Comparison of phase composition, morphology and electrochemical property for Li3−xNaxV2(PO4)3 (x=0.5, 1.5 and 2.0) as lithium storage cathode materials

International Nuclear Information System (INIS)

Mao, Jinli; Shao, Lianyi; Li, Peng; Lin, Xiaoting; Shui, Miao; Long, Nengbing; Shu, Jie

2015-01-01

Graphical abstract: Display Omitted -- Highlights: •Li 3−x Na x V 2 (PO 4 ) 3 is prepared by a solid-state reaction method. •Li 2.5 Na 0.5 V 2 (PO 4 ) 3 is a three-phase mixture. •Both Li 1.5 Na 1.5 V 2 (PO 4 ) 3 and LiNa 2 V 2 (PO 4 ) 3 are two-phase composite. •Lithium ion diffusion coefficient is detected by cyclic voltammetry. •Structural change of LiNa 2 V 2 (PO 4 ) 3 is observed by in-situ XRD. -- Abstract: Three Li 3-x Na x V 2 (PO 4 ) 3 (x=0.5, 1.5 and 2.0) samples are synthesized by a traditional solid-state reaction method in this work. Their phase composition, surface morphology and electrochemical property are described and compared by using various physical/chemical methods. Phase analysis results reveal that Li 2.5 Na 0.5 V 2 (PO 4 ) 3 consists of monoclinic Li 3 V 2 (PO 4 ) 3 , rhombohedral Li 3 V 2 (PO 4 ) 3 and rhombohedral Na 3 V 2 (PO 4 ) 3. While, both Li 1.5 Na 1.5 V 2 (PO 4 ) 3 and LiNa 2 V 2 (PO 4 ) 3 are the two-phase mixture consisted of rhombohedral Li 3 V 2 (PO 4 ) 3 and rhombohedral Na 3 V 2 (PO 4 ) 3 . Electrochemical testing results reveal that LiNa 2 V 2 (PO 4 ) 3 and Li 1.5 Na 1.5 V 2 (PO 4 ) 3 can deliver the initial discharge capacities of 101.4 mAh g −1 and 108.6 mAh g −1 with a long potential plateau at 3.69 V, respectively. In contrast, Li 2.5 Na 0.5 V 2 (PO 4 ) 3 presents an initial discharge capacity of 111.7 mAh g −1 with four potential plateaus. High lithium ion diffusion coefficient in Li 2.5 Na 0.5 V 2 (PO 4 ) 3 indicates that the existence of monoclinic Li 3 V 2 (PO 4 ) 3 phase can improve the ionic conductivity and then be responsible for good electrochemical performance. Besides, in-situ X-ray diffraction observation of LiNa 2 V 2 (PO 4 ) 3 demonstrates that the phase transition is not fully reversible but quasi-reversible during the lithiation-delithiation process. The partial irreversibility of structural evolution for LiNa 2 V 2 (PO 4 ) 3 induces the capacity loss upon repeated cycles

Analysis of tritium production in concentric spheres of oralloy and 6LiD irradiated by 14-MeV neutrons

International Nuclear Information System (INIS)

Fawcett, L.R. Jr.; Roberts, R.R. II; Hunter, R.E.

1988-03-01

Tritium production and activation of radiochemical detector foils in a sphere of 6 LiD with an oralloy core irradiated by a central source of 14-MeV neutrons have been calculated and compared with experimental measurements. The experimental assembly consisted of an oralloy sphere surrounded by three solid 6 LiD concentric shells with ampules of 6 LiH and 7 LiH and activation foils located in several positions throughout the assembly. The Los Alamos Monte Carlo Neutron Photon Transport Code (MCNP) was used to calculate neutron transport throughout the system, tritium production in the ampules, and foil activation. The overall experimentally observed-to-calculated ratios of tritium production were 0.996 +- 2.5% in 6 Li ampules and 0.903 +- 5.2% in 7 Li ampules. Observed-to-calculated ratios for foil activation are also presented. 11 refs., 4 figs., 7 tabs

Test of level density models from reactions of Li6 on Fe58 and Li7 on Fe57

Science.gov (United States)

Oginni, B. M.; Grimes, S. M.; Voinov, A. V.; Adekola, A. S.; Brune, C. R.; Carter, D. E.; Heinen, Z.; Jacobs, D.; Massey, T. N.; O'Donnell, J. E.; Schiller, A.

2009-09-01

The reactions of Li6 on Fe58 and Li7 on Fe57 have been studied at 15 MeV beam energy. These two reactions produce the same compound nucleus, Cu64. The charged particle spectra were measured at backward angles. The data obtained have been compared with Hauser-Feshbach model calculations. The level density parameters of Ni63 and Co60 have been obtained from the particle evaporation spectra. We also find contributions from the break up of the lithium projectiles to the low energy region of the α spectra.

Effect of MnO doping on the structure, microstructure and electrical properties of the (K,Na,Li)(Nb,Ta,Sb)O3 lead-free piezoceramics

International Nuclear Information System (INIS)

Rubio-Marcos, F.; Marchet, P.; Vendrell, X.; Romero, J.J.; Remondiere, F.; Mestres, L.; Fernandez, J.F.

2011-01-01

Highlights: · MnO doping effects on structure and properties of (K,Na,Li)(Nb,Ta,Sb)O 3 piezoceramics. · The structure changes towards an orthorhombic symmetry for higher MnO concentrations. · High doping levels induce a tetragonal tungsten-bronze secondary phase. · Mn 2+ doping modifies the phase transition temperature and the piezoelectric properties. · Manganese doping increases the mechanical quality factor Q m . - Abstract: Mn 2+ -doped (K,Na,Li)(Nb,Ta,Sb)O 3 lead-free piezoelectric ceramics have been prepared by a conventional sintering technique. The effects of Mn 2+ doping on the phase structure, microstructure and ferro-piezoelectric properties of the ceramics have been evaluated. MnO doping modifies the (K,Na,Li)(Nb,Ta,Sb)O 3 structure, giving rise to the appearance of a TTB-like secondary phase and to changes on the orthorhombic to tetragonal phase transition temperature. The modification of this temperature induces a reduction of the piezoelectric constants, which is accompanied by an increase on the mechanical quality factor. Mn 2+ ions incorporate into the perovskite structure in different off ways depending on their concentration.

Two-proton pickup studies with the (6Li,8B) reaction

Energy Technology Data Exchange (ETDEWEB)

Weisenmiller, R.B.

1976-12-03

The (/sup 6/Li,/sup 8/B) reaction has been investigated on targets of /sup 26/Mg, /sup 24/Mg, /sup 16/O, /sup 13/C, /sup 12/C, /sup 11/B, /sup 10/B, and /sup 9/Be at a bombarding energy of 80.0 MeV, and on targets of /sup 16/O, /sup 12/C, /sup 9/Be, /sup 7/Li, and /sup 6/Li at a bombarding energy of 93.3 MeV. Only levels consistent with direct, single-step two-proton pickup reaction mechanisms were observed to be strongly populated. On T/sub z/ = 0 targets, the spectroscopic selectivity of this reaction resembles that of the analogous (p,t) reaction. Additionally, these data demonstrate the dominance of spatially symmetric transfer of the two protons. On T/sub z/ greater than 0 targets the (/sup 6/Li,/sup 8/B) reaction was employed to locate two previously unreported levels (at 7.47 +- 0.05 MeV and 8.86 +- 0.07 MeV) in the T/sub z/ = 2 nuclide /sup 24/Ne and to establish the low-lying 1p-shell states in the T/sub z/ = /sup 3///sub 2/ nuclei /sup 11/Be, /sup 9/Li, and /sup 7/He. However, no evidence was seen for any narrow levels in the T/sub z/ = /sup 3///sub 2/ nuclide /sup 5/H nor for any narrow excited states in /sup 7/He. The angular distributions reported here are rather featureless and decrease monotonically with increasing angle. This behavior can be shown by a semi-classical reaction theory to be a consequence of the reaction kinematics. A semi-classical approach also suggests that the kinematic term in the transition matrix element is only weakly dependent upon the angular momentum transfer (which is consistent with simple Distorted Wave Born Approximation calculations). However, only qualitative agreement was obtained between the observed relative transition yields and semi-classical predictions, using the two-nucleon coefficients of fractional parentage of Cohen and Kurath, probably due to the limitations of the semi-classical reaction theory.

Laponite Na+0.7[(Si8Mg5.5Li0.3)O20(OH)4]–0.7

Indian Academy of Sciences (India)

Si8Mg5.5Li0.3)O20(OH)4]–0.7. Negative charges are counterbalanced by Na+ ions present in the interlayer. Electrostatic screening length at pH 10 ≈30 nm. Effective maximum volume increases by a factor of 60. Thus, for less than 1 volume ...

Large-Area Neutron Detector based on Li-6 Pulse Mode Ionization Chamber

International Nuclear Information System (INIS)

Chung, K.; Ianakiev, K.D.; Swinhoe, M.T.; Makela, M.F.

2005-01-01

Prototypes of a Li-6 Pulse Mode Ionization Chamber (LiPMIC) have been in development for the past two years for the purpose of providing large-area neutron detector. this system would be suitable for remote deployment for homeland security and counterterrorism needs at borders, ports, and nuclear facilities. A prototype of LiPMIC is expected to provide a similar level of performance to the current industry-standard, He-3 proportional counters, while keeping the initial cost of procurement down by an order of magnitude, especially where large numbers of detectors are required. The overall design aspect and the efficiency optimization process is discussed. Specifically, the MCNP simulations of a single-cell prototype were performed and benchmarked with the experimental results. MCNP simulations of a three dimensional array design show intrinsic efficiency comparable to that of an array of He-3 proportional counters. LiPMIC has shown steady progress toward fulfilling the design expectations and future design modification and optimization are discussed.

Parsec-scale Variations in the 7Li I/6Li I Isotope Ratio Toward IC 348 and the Perseus OB 2 Association

Science.gov (United States)

Knauth, D. C.; Taylor, C. J.; Ritchey, A. M.; Federman, S. R.; Lambert, D. L.

2017-01-01

Measurements of the lithium isotopic ratio in the diffuse interstellar medium from high-resolution spectra of the Li I λ6708 resonance doublet have now been reported for a number of lines of sight. The majority of the results for the 7Li/6Li ratio are similar to the solar system ratio of 12.2, but the line of sight toward o Per, a star near the star-forming region IC 348, gave a ratio of about two, the expected value for gas exposed to spallation and fusion reactions driven by cosmic rays. To examine the association of IC 348 with cosmic rays more closely, we measured the lithium isotopic ratio for lines of sight to three stars within a few parsecs of o Per. One star, HD 281159, has 7Li/6Li ≃ 2 confirming production by cosmic rays. The lithium isotopic ratio toward o Per and HD 281159 together with published analyses of the chemistry of interstellar diatomic molecules suggest that the superbubble surrounding IC 348 is the source of the cosmic rays. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

Li-promoted sodium zirconate as a CO{sub 2} absorbent at high temperatures; Zirconato de sodio promovido con Li como absorbente de CO{sub 2} a alta temperatura

Energy Technology Data Exchange (ETDEWEB)

Guzman Velderrain, V.; Barraza Jimenez, D.; Lardizabal Gutierrez, D.; Delgado Vigil, D.; Salinas Gutierrez, J.; Lopez Ortiz, A.; Collins-Martinez, V. [Centro de Investigacion en Materiales Avanzados S. C., Chihuahua, Chihuahua (Mexico)]. E-mail: virginia.collins@cimav.edu.mx

2009-09-15

In processes to produce hydrogen from fossil fuels, CO{sub 2} capture at high temperatures has played a crucial role in their conversion into energy-efficient processes. One example is steam reformer methane improved with absorption (SER), where CO{sub 2} capture at high temperatures (600 degrees Celsius) provides an energy savings of {approx_equal} 23% over conventional reformer processes (SMR). An important part of this concept is solid CO{sub 2} absorption, which must have adequate absorption capacity and rapid absorption/regeneration kinetics. Recently, synthetic CO{sub 2} absorbents have been developed that consist of mixed Li oxides. Previous studies conducted in our laboratory report that the absorption/regeneration properties of sodium zirconate (Na{sub 2}ZrO{sub 3}) are higher than Li-oxides. The objective of the present work is to increase the absorption capacity of Na{sub 2}ZrO{sub 3} at high temperatures without significantly affecting the kinetics of its absorption and regeneration, with Li promotion. The Na{sub 2}ZrO{sub 3} was synthesized by reaction in a solid state and impregnated with LiNO{sub 3} at different Li/Na ratios: 0, 0.03, 0.05, 0.1 and 0.25 (NZ, NZL3, NZL5, NZL10, NZL25). The characterization consisted of XRD and SEM. The evaluation as an absorbent was performed with TGA at 600 degrees Celsius in 80% CO{sub 2} (absorption) and 800 degrees Celsius in air (regeneration). While XRD shows only the Na{sub 2}ZrO{sub 3} structure in all the samples, the promoted samples present a signal shift with respect to Na{sub 2}ZrO{sub 3}, which is attributed to the substitution of Na atoms with Li. The TGA results indicate that the addition of Li to the Na{sub 2}ZrO{sub 3} structure does not significantly modify the absorption or regeneration kinetics. As the Li contents in the Na{sub 2}ZrO{sub 3} increase, the amount of CO{sub 2} capture increases up to a limit between 10 and 25% mol of Li. This is due to the displaced sodium presumably tending to form

NMR study of the paramagnetic state of low-dimensional magnets LiCu{sub 2}O{sub 2} and NaCu{sub 2}O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Sadykov, A. F., E-mail: sadykov@imp.uran.ru; Piskunov, Yu. V.; Gerashchenko, A. P.; Ogloblichev, V. V.; Smol’nikov, A. G.; Verkhovskii, S. V.; Arapova, I. Yu.; Volkova, Z. N.; Mikhalev, K. N. [Russian Academy of Sciences, Mikheev Institute of Metal Physics, Ural Branch (Russian Federation); Bush, A. A. [Moscow State Technical University of Radio Engineering, Electronics, and Automation (Russian Federation)

2017-02-15

A comprehensive NMR study of the magnetic properties of single crystal LiCu{sub 2}O{sub 2} (LCO) and NaCu{sub 2}O{sub 2} (NCO) is carried out in the paramagnetic region of the compounds for various orientations of single crystals in an external magnetic field. The values of the electric-field gradient (EFG) tensor, as well as the dipole and transferred hyperfine magnetic fields for {sup 63,65}Cu, {sup 7}Li, and {sup 23}Na nuclei are determined. The results are compared with the data obtained in previous NMR studies of the magnetically ordered state of LCO/NCO cuprates.

Towards 6Li-40K ground state molecules

International Nuclear Information System (INIS)

Brachmann, Johannes Felix Simon

2013-01-01

The production of a quantum gas with strong long - range dipolar interactions is a major scientific goal in the research field of ultracold gases. In their ro - vibrational ground state Li-K dimers possess a large permanent dipole moment, which could possibly be exploited for the realization of such a quantum gas. A production of these molecules can be achieved by the association of Li and K at a Feshbach resonance, followed by a coherent state transfer. In this thesis, detailed theoretical an experimental preparations to achieve state transfer by means of Stimulated Raman Adiabatic Passage (STIRAP) are described. The theoretical preparations focus on the selection of an electronically excited molecular state that is suitable for STIRAP transfer. In this context, molecular transition dipole moments for both transitions involved in STIRAP transfer are predicted for the first time. This is achieved by the calculation of Franck-Condon factors and a determination of the state in which the 6 Li- 40 K Feshbach molecules are produced. The calculations show that state transfer by use of a single STIRAP sequence is experimentally very well feasible. Further, the optical wavelengths that are needed to address the selected states are calculated. The high accuracy of the data will allow to carry out the molecular spectroscopy in a fast and efficient manner. Further, only a comparatively narrow wavelength tuneability of the spectroscopy lasers is needed. The most suitable Feshbach resonance for the production of 6 Li- 40 K molecules at experimentally manageable magnetic field strengths is occurring at 155 G. Experimentally, this resonance is investigated by means of cross-dimensional relaxation. The application of the technique at various magnetic field strengths in the vicinity of the 155 G Feshbach resonance allows a determination of the resonance position and width with so far unreached precision. This reveals the production of molecules on the atomic side of the resonance

Anion Redox Chemistry in the Cobalt Free 3d Transition Metal Oxide Intercalation Electrode Li[Li0.2Ni0.2Mn0.6]O2.

Science.gov (United States)

Luo, Kun; Roberts, Matthew R; Guerrini, Niccoló; Tapia-Ruiz, Nuria; Hao, Rong; Massel, Felix; Pickup, David M; Ramos, Silvia; Liu, Yi-Sheng; Guo, Jinghua; Chadwick, Alan V; Duda, Laurent C; Bruce, Peter G

2016-09-07

Conventional intercalation cathodes for lithium batteries store charge in redox reactions associated with the transition metal cations, e.g., Mn(3+/4+) in LiMn2O4, and this limits the energy storage of Li-ion batteries. Compounds such as Li[Li0.2Ni0.2Mn0.6]O2 exhibit a capacity to store charge in excess of the transition metal redox reactions. The additional capacity occurs at and above 4.5 V versus Li(+)/Li. The capacity at 4.5 V is dominated by oxidation of the O(2-) anions accounting for ∼0.43 e(-)/formula unit, with an additional 0.06 e(-)/formula unit being associated with O loss from the lattice. In contrast, the capacity above 4.5 V is mainly O loss, ∼0.08 e(-)/formula. The O redox reaction involves the formation of localized hole states on O during charge, which are located on O coordinated by (Mn(4+)/Li(+)). The results have been obtained by combining operando electrochemical mass spec on (18)O labeled Li[Li0.2Ni0.2Mn0.6]O2 with XANES, soft X-ray spectroscopy, resonant inelastic X-ray spectroscopy, and Raman spectroscopy. Finally the general features of O redox are described with discussion about the role of comparatively ionic (less covalent) 3d metal-oxygen interaction on anion redox in lithium rich cathode materials.

The existence and stability of the anions matching the MFk+2- formula (M = Li, Na, K, Be, Mg, Ca, B, Al, Ga)

Science.gov (United States)

Marchaj, Marzena; Freza, Sylwia; Skurski, Piotr

2013-02-01

The electronic stabilities of the MFk+2- anions (where M = Li, Na, K, Be, Mg, Ca, B, Al, Ga; and k is the maximal formal valence of atom M) were investigated at the OVGF/6-311 + G(3df) level. The vertical electron detachment energies (VDE) of the anions examined were found to be large (7.1-10.1 eV) albeit not significantly exceeding those for the corresponding MFk+1- superhalogen anions. Even though all the MFk+2- species studied were predicted to be both geometrically and electronically stable, some of them turned out to be thermodynamically unstable (i.e., susceptible to the F atom loss).

Fusion cross sections measurement for 6Li + 159Tb

International Nuclear Information System (INIS)

Pradhan, M.K.; Mukherjee, A.; Kshetri, R.; Roy, Subinit; Basu, P.; Goswami, A.; Saha Sarkar, M.; Ray, M.; Parkar, V.; Santra, S.; Kailas, S.; Palit, R.

2009-01-01

In order to investigate the effect of projectile breakup threshold energy on fusion in mass region around A∼170, we have carried out a systematic investigation of the fusion (both CF and ICF) cross sections for the systems 11 B, 10 B + 159 Tb and 7 Li + 159 Tb at energies near and close to the barrier where 11 B was considered to be a strongly bound nucleus. The nucleus 10 B has a α-separation energy of 4.5 MeV. The measurements show that the extent of suppression of CF cross sections is correlated with the α-separation energies of the projectiles. As a further continuation of this work, we have recently carried out fusion excitation function measurement for the system 6 Li + 159 Tb (Coulomb barrier 27 MeV) at energies near and close to the barrier

Site-different structures from dilithium hexaboride (Li2b6) to dimagnesium hexaboride (Mg2B6) by first-principles

International Nuclear Information System (INIS)

Aydın, Sezgin

2013-01-01

Highlights: •All structures are thermodynamically stable. All structures are metallic. •Boron sub-lattice have negative-charged atoms and more covalent bonds. •The inter-octahedral binding is more covalent than inner-octahedral binding. •All structures are also mechanically stable. -- Abstract: The structural, mechanical, electronic and bonding properties of dilithium hexaboride (Li 2 B 6 ) and isostructural hypothetic compounds obtained by replacing Li atoms in different sites to magnesium atoms have been investigated by first-principles density functional pseudopotential plane–wave calculations. It is shown that calculated lattice parameters of Li 2 B 6 agree with the experimental results. All of designed hypothetical structures have negative formation enthalpies, thus all of them are thermodynamically stable and the most stable structure is Mg 2 B 6 . At the same time, from calculated single crystal elastic constants, it is shown that all structures are mechanically stable and related mechanical properties such as bulk, shear and Young moduli are calculated. It is shown that adding magnesium to the structure of Li 2 B 6 is decreasing values of the moduli. Further, hardnesses of the structures are determined theoretically and it is obtained that hardness exhibits same trend with the moduli. From electronic structure calculations including band structure and site-dependent density of states, all structures are metallic, and fully magnesium substituted structure (Mg 2 B 6 ) has the highest metallicity among the structures. Additionally, bonding nature of the structures are analyzed by using electron density maps, Mulliken atomic charges and bond overlap populations

Structural transformation during Li/Na insertion and theoretical cyclic voltammetry of the δ-NH4V4O10 electrode: a first-principles study.

Science.gov (United States)

Sarkar, Tanmay; Kumar, Parveen; Bharadwaj, Mridula Dixit; Waghmare, Umesh

2016-04-14

A double layer δ-NH4V4O10, due to its high energy storage capacity and excellent rate capability, is a very promising cathode material for Li-ion and Na-ion batteries for large-scale renewable energy storage in transportation and smart grids. While it possesses better stability, and higher ionic and electronic conductivity than the most widely explored V2O5, the mechanisms of its cyclability are yet to be understood. Here, we present a theoretical cyclic voltammetry as a tool based on first-principles calculations, and uncover structural transformations that occur during Li(+)/Na(+) insertion (x) into (Lix/Nax)NH4V4O10. Structural distortions associated with single-phase and multi-phase structural changes during the insertion of Li(+)/Na(+), identified through the analysis of voltage profile and theoretical cyclic voltammetry are in agreement with the reported experimental electrochemical measurements on δ-NH4V4O10. We obtain an insight into its electronic structure with a lower band gap that is responsible for the high rate capability of (Lix/Nax) δ-NH4V4O10. The scheme of theoretical cyclic voltammetry presented here will be useful for addressing issues of cyclability and energy rate in other electrode materials.

Passivation behavior of Type 304 stainless steel in a non-aqueous alkyl carbonate solution containing LiPF6 salt

International Nuclear Information System (INIS)

Myung, Seung-Taek; Sasaki, Yusuke; Saito, Takamitsu; Sun, Yang-Kook; Yashiro, Hitoshi

2009-01-01

Passivation behavior of type 304 stainless steel in a non-aqueous alkyl carbonate solution containing LiPF 6 salt was studied using electrochemical polarization, X-ray photoelectron spectroscopy (XPS) and time of flight-secondary ion mass spectroscopy (ToF-SIMS). Cathodic polarization to 0 V vs. Li/Li + resulted in most but not complete reduction of the air-formed film from oxides to metal on the stainless steel, as confirmed by XPS. For complete elimination of the air-formed film, the surface of the stainless steel was scratched under anodic polarization conditions. At 3 V vs. Li/Li + where an anodic current peak appeared, only an indistinct layer was recognized on the newly scratched surface, according to ToF-SIMS analysis. Above 4 V vs. Li/Li + , substantial passive films were formed, which were composed of oxides and fluorides of iron and chromium. The origin of oxide was due to water contained in the non-aqueous alkyl carbonate solution, and that of fluorides were the result of the decomposition of electrolytic salt, LiPF 6 , especially at higher potential. The resultant passive films were stable in the non-aqueous alkyl carbonate solution containing LiPF 6 salt.

Study of reaction mechanism for 12C(14N, 6Li) by angular correlation measurement

International Nuclear Information System (INIS)

Goldberg, V.Z.; Golovkov, M.S.; Rogatchev, G.V.; Barrov, S.P.; Zurmuhle, R.W.; Liu, Z.; Benton, D.R.; Miao, Y.; Lee, C.; Wimer, N.G.; Murgatroyd, J.T.; Li, X.

1999-01-01

An angular correlation for the reaction 12 C ( 14 N, 6 Li) 20 Ne* (α) populating the 8.78 MeV (6 + ) level in 20 Ne is measured at 48 MeV incident 14 N energy. 6 Li is registered for 0-degree geometry in coincidence with α particles from the 20 Ne excited state decay. The results shows that 20% was the upper limit for the contribution of compound nucleus formation. Possible main direct mechanisms of the reaction are discussed [ru

(1−x)[(K$_{0.5}$Na$_{0.5}$)NbO$_3$–LiSbO$_3

Indian Academy of Sciences (India)

Lead-free piezoelectric ceramics ( 1 − x ) [0.95(K 0.5 Na 0.5 )NbO 3 –0.05LiSbO 3 ]– x BiFe 0.8 Co 0.2 O 3 (KNN–LS– x BFC) were prepared by a conventional sintering technique. The effect of BFC content on the structure, piezoelectricand electrical properties of KNN–LS ceramics was investigated. The results reveal that ...

Study on fast luminescence component induced by gamma-rays in Ce doped LiCaAlF6 scintillators

International Nuclear Information System (INIS)

Watanabe, Kenichi; Kondo, Yoshiyuki; Yamazaki, Atsushi; Uritani, Akira; Iguchi, Tetsuo; Kawaguchi, Noriaki; Fukuda, Kentaro; Ishizu, Sumito; Yanagida, Takayuki; Fujimoto, Yutaka; Yoshikawa, Akira

2014-01-01

We discuss the origin of the fast luminescence component induced by fast electrons generated in gamma-ray interactions in Ce doped LiCaAlF 6 scintillators. Although the slow luminescence component induced by Ce 3+ emissions depends on the Ce concentration in the LiCaAlF 6 scintillator, the fast component is independent. The fast component is suggested to be generated in the host matrix of the LiCaAlF 6 crystal. From quantitative considerations based on Frank–Tamm equation, which shows the light yield of the Cherenkov radiation, the Cherenkov radiation was determined as the origin of the fast component. We, additionally, found that the slow rise time of main Ce 3+ emissions in the Ce:LiCaAlF 6 scintillator plays an important role to perform the pulse shape discrimination. - Highlights: • The fast luminescence in Ce:LiCaAlF 6 scintillator is generated in the host matrix. • The origin of the fast luminescence is determined as the Cherenkov radiation. • The slow rise time also plays an important role to perform PSD

Influence of the composition to the physical properties of NaF-LiF-LaF3 melt liquid systems

Directory of Open Access Journals (Sweden)

L. A. Bulavin

2013-06-01

Full Text Available Influence of the chemical composition of NaF-LiF-LaF3 system on temperature dependence of electrical con-ductivity, viscosity and thermoelectric power has been studied in a wide temperature range between 600 and 1500 К. The obtained results could help in design of the molten salt reactor blanket.

Growth of solid solutions with colquiriite structure LiCa0,2Sr0,8AlF6: Ce3+

International Nuclear Information System (INIS)

Shavelev, A A; Nizamutdinov, A S; Semashko, V V; Marisov, M A

2014-01-01

Aim of this work were experiments on growing new materials based on fluoride crystals with the colquiriite structure LiSr 0,8 Ca 0,2 F 6 , as well as the study of their phase composition. It is shown that for a series of crystals LiSr 0,8 Ca 0,2 F 6 distribution of reflections observed corresponds to the colquiriite structure, and the dependence of the lattice constant in the transition from LiCaAlF 6 crystal to LiSrAlF 6 crystal is linear. Also it found that absorption coefficient in mixed samples is much larger than in not mixed

First direct measurement of the 2H(α,γ)6Li cross section at big bang energies and the primordial lithium problem.

Science.gov (United States)

Anders, M; Trezzi, D; Menegazzo, R; Aliotta, M; Bellini, A; Bemmerer, D; Broggini, C; Caciolli, A; Corvisiero, P; Costantini, H; Davinson, T; Elekes, Z; Erhard, M; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Junker, M; Lemut, A; Marta, M; Mazzocchi, C; Prati, P; Rossi Alvarez, C; Scott, D A; Somorjai, E; Straniero, O; Szücs, T

2014-07-25

Recent observations of (6)Li in metal poor stars suggest a large production of this isotope during big bang nucleosynthesis (BBN). In standard BBN calculations, the (2)H(α,γ)(6)Li reaction dominates (6)Li production. This reaction has never been measured inside the BBN energy region because its cross section drops exponentially at low energy and because the electric dipole transition is strongly suppressed for the isoscalar particles (2)H and α at energies below the Coulomb barrier. Indirect measurements using the Coulomb dissociation of (6)Li only give upper limits owing to the dominance of nuclear breakup processes. Here, we report on the results of the first measurement of the (2)H(α,γ)(6)Li cross section at big bang energies. The experiment was performed deep underground at the LUNA 400 kV accelerator in Gran Sasso, Italy. The primordial (6)Li/(7)Li isotopic abundance ratio has been determined to be (1.5 ± 0.3) × 10(-5), from our experimental data and standard BBN theory. The much higher (6)Li/(7)Li values reported for halo stars will likely require a nonstandard physics explanation, as discussed in the literature.

VUV spectroscopy of Tm3+ and Mn2+ doped LiSrAlF6

International Nuclear Information System (INIS)

True, M.; Kirm, M.; Negodine, E.; Vielhauer, S.; Zimmerer, G.

2004-01-01

LiSrAlF 6 (LiSAF) crystals doped with either Tm 3+ or Mn 2+ were obtained by solid-state reaction and investigated spectroscopically using synchrotron radiation in the vacuum-ultra-violet and ultra-violet spectral regions. In the Tm 3+ doped LiSAF crystals, the slow spin-forbidden 5d-4f emission peaking at 166 nm with a lifetime of at least 1 μs was observed. The respective excitation spectrum consists of several bands in the range of 160-110 nm arising due to the 4f-5d absorption. The f-f emissions of Tm 3+ are well excited in the range of 135-110 nm, but not under excitation into the lower lying d-bands. The excitation mechanisms of different emissions will be discussed including the F - to Tm 3+ charge transfer excitation peaking at 127 nm in LiSAF. The characteristic broad 4 T 1 → 6 A 1 emission band of Mn 2+ peaking at 508 (504) nm was observed in LiSAF:Mn 2+ crystal at 10 (300) K. Three intense excitation bands, tentatively ascribed to the 3d-4s transitions of Mn 2+ , were revealed in the range of 170-110 nm

New alkali-metal- and 2-phenethylamine-intercalated superconductors Ax(C8H11N)yFe1-zSe (A = Li, Na) with the largest interlayer spacings and Tc ∼ 40 K

International Nuclear Information System (INIS)

Hatakeda, Takehiro; Noji, Takashi; Sato, Kazuki; Kawamata, Takayuki; Kato, Masatsune; Koike, Yoji

2016-01-01

New FeSe-based intercalation superconductors, A x (C 8 H 11 N) y Fe 1-z Se (A = Li, Na), with T c = 39-44 K have been successfully synthesized via the intercalation of alkali metals and 2-phenethylamine into FeSe. The interlayer spacings, namely, the distances between neighboring Fe layers, d, of A x (C 8 H 11 N) y Fe 1-z Se (A = Li, Na) are 19.04(6) and 18.0(1) Å, respectively. These d values are the largest among those of the FeSe-based intercalation compounds and are understood to be due to the intercalation of two molecules of 2-phenethylamine in series perpendicular to the FeSe layers. It appears that the relationship between T c and d in the FeSe-based intercalation superconductors is not domic but T c is saturated at ∼45 K, which is comparable to the T c values of single-layer FeSe films, for d ≥ 9 Å. (author)

Lithium fluxes indicate presence of Na-Cl cotransport (NCC) in human lens epithelial cells.

Science.gov (United States)

Lauf, Peter K; Chimote, Ameet A; Adragna, Norma C

2008-01-01

During regulatory volume decrease (RVD) of human lens epithelial cells (hLECs) by clotrimazole (CTZ)-sensitive K fluxes, Na-K-2Cl cotransport (NKCC) remains active and K-Cl cotransport (KCC) inactive. To determine whether such an abnormal behavior was caused by RVD-induced cell shrinkage, NKCC was measured in the presence of either CTZ or in high K media to prevent RVD. NKCC transports RbCl + NaCl, and LiCl + KCl; thus ouabain-insensitive, bumetanide-sensitive (BS) or Cl-dependent (ClD) Rb and Li fluxes were determined in hyposmotic high NaCl media with CTZ, or in high KCl media alone, or with sulfamate (Sf) or nitrate as Cl replacement at varying Rb, Li or Cl mol fractions (MF). Unexpectedly, NKCC was inhibited by 80% with CTZ (IC(50) = 31 microM). In isosmotic (300 mOsM) K, Li influx was approximately 1/3 of Rb influx in Na, 50% lower in Sf, and bumetanide-insensitive (BI). In hypotonic (200 mOsM) K, only the ClD but not BS Li fluxes were detected. At Li MFs from 0.1-1, Li fluxes fitted a bell-shaped curve maxing at approximately 0.6 Li MF, with the BS fluxes equaling approximately 1/4 of the ClD-Li influx. The difference, i.e. the BI/ClD Li influx, saturated with increasing Li and Cl MFs, with K(ms) for Li of 11 with, and 7 mM without K, and of approximately 46 mM for Cl. Inhibition of this K-independent Li influx by thiazides was weak whilst furosemide (<100 microM) was ineffective. Reverse transcription polymerase chain reaction and Western blots verified presence of both NKCC1 and Na-Cl cotransport (NCC). In conclusion, in hyposmotic high K media, which prevents CTZ-sensitive K flux-mediated RVD in hLECs, NKCC1, though molecularly expressed, was functionally silent. However, a K-independent and moderately thiazide-sensitive ClD-Li flux, i.e. LiCC, likely occurring through NCC was detected operationally and molecularly. (c) 2008 S. Karger AG, Basel.

Three-Body Recombination near a Narrow Feshbach Resonance in Li 6

Science.gov (United States)

Li, Jiaming; Liu, Ji; Luo, Le; Gao, Bo

2018-05-01

We experimentally measure and theoretically analyze the three-atom recombination rate, L3, around a narrow s -wave magnetic Feshbach resonance of Li 6 - Li 6 at 543.3 G. By examining both the magnetic field dependence and, especially, the temperature dependence of L3 over a wide range of temperatures from a few μ K to above 200 μ K , we show that three-atom recombination through a narrow resonance follows a universal behavior determined by the long-range van der Waals potential and can be described by a set of rate equations in which three-body recombination proceeds via successive pairwise interactions. We expect the underlying physical picture to be applicable not only to narrow s wave resonances, but also to resonances in nonzero partial waves, and not only at ultracold temperatures, but also at much higher temperatures.

Development of Sulfide Solid Electrolytes and Interface Formation Processes for Bulk-Type All-Solid-State Li and Na Batteries

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Akitoshi, E-mail: hayashi@chem.osakafu-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka (Japan); Sakuda, Atsushi [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka (Japan); Department of Energy and Environment, Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka (Japan); Tatsumisago, Masahiro [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka (Japan)

2016-07-15

All-solid-state batteries with inorganic solid electrolytes (SEs) are recognized as an ultimate goal of rechargeable batteries because of their high safety, versatile geometry, and good cycle life. Compared with thin-film batteries, increasing the reversible capacity of bulk-type all-solid-state batteries using electrode active material particles is difficult because contact areas at solid–solid interfaces between the electrode and electrolyte particles are limited. Sulfide SEs have several advantages of high conductivity, wide electrochemical window, and appropriate mechanical properties, such as formability, processability, and elastic modulus. Sulfide electrolyte with Li{sub 7}P{sub 3}S{sub 11} crystal has a high Li{sup +} ion conductivity of 1.7 × 10{sup −2} S cm{sup −1} at 25°C. It is far beyond the Li{sup +} ion conductivity of conventional organic liquid electrolytes. The Na{sup +} ion conductivity of 7.4 × 10{sup −4} S cm{sup −1} is achieved for Na{sub 3.06}P{sub 0.94}Si{sub 0.06}S{sub 4} with cubic structure. Moreover, formation of favorable solid–solid interfaces between electrode and electrolyte is important for realizing solid-state batteries. Sulfide electrolytes have better formability than oxide electrolytes. Consequently, a dense electrolyte separator and closely attached interfaces with active material particles are achieved via “room-temperature sintering” of sulfides merely by cold pressing without heat treatment. Elastic moduli for sulfide electrolytes are smaller than that of oxide electrolytes, and Na{sub 2}S–P{sub 2}S{sub 5} glass electrolytes have smaller Young’s modulus than Li{sub 2}S–P{sub 2}S{sub 5} electrolytes. Cross-sectional SEM observations for a positive electrode layer reveal that sulfide electrolyte coating on active material particles increases interface areas even with a minimum volume of electrolyte, indicating that the energy density of bulk-type solid-state batteries is enhanced. Both surface coating

P-wave Feshbach resonances of ultracold 6Li

International Nuclear Information System (INIS)

Zhang, J.; Kempen, E.G.M. van; Bourdel, T.; Cubizolles, J.; Chevy, F.; Teichmann, M.; Tarruell, L.; Salomon, C.; Khaykovich, L.; Kokkelmans, S.J.J.M.F.

2004-01-01

We report the observation of three p-wave Feshbach resonances of 6 Li atoms in the lowest hyperfine state f=1/2. The positions of the resonances are in good agreement with theory. We study the lifetime of the cloud in the vicinity of the Feshbach resonances and show that, depending on the spin states, two- or three-body mechanisms are at play. In the case of dipolar losses, we observe a nontrivial temperature dependence that is well explained by a simple model

Systematics of the breakup probability function for {sup 6}Li and {sup 7}Li projectiles

Energy Technology Data Exchange (ETDEWEB)

Capurro, O.A., E-mail: capurro@tandar.cnea.gov.ar [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); Pacheco, A.J.; Arazi, A. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Carnelli, P.F.F. [CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); Fernández Niello, J.O. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); and others

2016-01-15

Experimental non-capture breakup cross sections can be used to determine the probability of projectile and ejectile fragmentation in nuclear reactions involving weakly bound nuclei. Recently, the probability of both type of dissociations has been analyzed in nuclear reactions involving {sup 9}Be projectiles onto various heavy targets at sub-barrier energies. In the present work we extend this kind of systematic analysis to the case of {sup 6}Li and {sup 7}Li projectiles with the purpose of investigating general features of projectile-like breakup probabilities for reactions induced by stable weakly bound nuclei. For that purpose we have obtained the probabilities of projectile and ejectile breakup for a large number of systems, starting from a compilation of the corresponding reported non-capture breakup cross sections. We parametrize the results in accordance with the previous studies for the case of beryllium projectiles, and we discuss their systematic behavior as a function of the projectile, the target mass and the reaction Q-value.

Lost in Translation (LiT): IUPHAR Review 6.

Science.gov (United States)

Dollery, Colin T

2014-05-01

Translational medicine is a roller coaster with occasional brilliant successes and a large majority of failures. Lost in Translation 1 ('LiT1'), beginning in the 1950s, was a golden era built upon earlier advances in experimental physiology, biochemistry and pharmacology, with a dash of serendipity, that led to the discovery of many new drugs for serious illnesses. LiT2 saw the large-scale industrialization of drug discovery using high-throughput screens and assays based on affinity for the target molecule. The links between drug development and university sciences and medicine weakened, but there were still some brilliant successes. In LiT3, the coverage of translational medicine expanded from molecular biology to drug budgets, with much greater emphasis on safety and official regulation. Compared with R&D expenditure, the number of breakthrough discoveries in LiT3 was disappointing, but monoclonal antibodies for immunity and inflammation brought in a new golden era and kinase inhibitors such as imatinib were breakthroughs in cancer. The pharmaceutical industry is trying to revive the LiT1 approach by using phenotypic assays and closer links with academia. LiT4 faces a data explosion generated by the genome project, GWAS, ENCODE and the 'omics' that is in danger of leaving LiT4 in a computerized cloud. Industrial laboratories are filled with masses of automated machinery while the scientists sit in a separate room viewing the results on their computers. Big Data will need Big Thinking in LiT4 but with so many unmet medical needs and so many new opportunities being revealed there are high hopes that the roller coaster will ride high again. © 2014 The British Pharmacological Society.

Intermetallic and metal-rich phases in the system Li-Ba-In-N

International Nuclear Information System (INIS)

Smetana, Volodymyr; Vajenine, Grigori V.; Kienle, Lorenz; Duppel, Viola; Simon, Arndt

2010-01-01

Three new intermetallic phases, BaLi 2.1 In 1.9 , BaLi 1.12 In 0.98 , and BaLi 1.06 In 1.16 and two subnitrides Li 35 In 45 Ba 39 N 9 and LiIn 2 Ba 3 N 0.83 have been synthesized and their crystal structures have been determined. According to single crystal X-ray diffraction data BaLi 2.1 In 1.9 and BaLi 1.12 In 0.98 crystallize with hexagonal symmetry (BaLi 2.1 In 1.9 : P6 3 /mmc, a=10.410(2), c=8.364(2) A, Z=6, V=785.0(2) A 3 ) and BaLi 1.12 In 0.98 : P6/mmm, a=17.469(1), c=10.6409(7) A, Z=30, V=2813.5(8) A 3 ), while BaLi 1.06 In 1.16 has a rhombohedral structure (R-3c, a=18.894(3), c=85.289(17) A, Z=276, V=26368(8) A 3 ). BaLi 2.1 In 1.9 is isostructural with the known phase BaLi 4 . The phase BaLi 1.12 In 0.98 is structurally related to Na 8 K 23 Cd 12 In 48 , while BaLi 1.06 In 1.16 is isostructural with Li 33.3 Ba 13.1 Ca 3 . A sample containing structurally similar BaLi 1.12 In 0.98 and BaLi 1.02 In 1.16 was also investigated by transmission electron microscopy. Li 35 In 45 Ba 39 N 9 and LiIn 2 Ba 3 N 0.83 crystallize with tetragonal (I-42m, a=15.299(2), c=30.682(6) A, Z=2, V=7182(2) A 3 ) and cubic (Fd-3m, a=14.913(2) A, Z=8, V=3316.7(7) A 3 ) symmetry, respectively. While the first-mentioned subnitride belongs to the Li 80 Ba 39 N 9 structure type, the second extends the structural family of Ba 6 In 4.78 N 2.72 . The structural features of the new compounds are discussed in comparison to the known phases and the results of total energy calculations. - Graphical abstract: One-dimensional chain of face-sharing centered icosahedra in BaLi 2.1 In 1.9

Geometric Magnetic Frustration in Li3Mg2OsO6 Studied with Muon Spin Relaxation

Science.gov (United States)

Carlo, J. P.; Derakhshan, S.; Greedan, J. E.

Geometric frustration manifests when the spatial arrangement of ions inhibits magnetic order. Typically associated with antiferromagnetically (AF)-correlated moments on triangular or tetrahedral lattices, frustration occurs in a variety of structures and systems, resulting in rich phase diagrams and exotic ground states. As a window to exotic physics revealed by the cancellation of normally dominant interactions, the research community has taken great interest in frustrated systems. One family of recent interest are the rock-salt ordered oxides A5BO6, in which the B sites are occupied by magnetic ions comprising a network of interlocked tetrahedra, and nonmagnetic ions on the A sites control the B oxidation state through charge neutrality. Here we will discuss studies of Li3Mg2OsO6 using muon spin relaxation (μSR), a highly sensitive local probe of magnetism. Previous studies of this family included Li5OsO6, which exhibits AF order below 50K with minimal evidence for frustration, and Li4MgReO6, which exhibits glassy magnetism. Li3Mg2RuO6, meanwhile, exhibits long-range AF, with the ordering temperature suppressed by frustration. But its isoelectronic twin, Li3Mg2OsO6 (5d3 vs. 4d3) exhibits very different behavior, revealed by μSR to be a glassy ground state below 12K. Understanding why such similar systems exhibit diverse ground-state behavior is key to understanding the nature of geometric magnetic frustration. Financial support from the Research Corporation for Science Advancement.

Electron transfer in keV Li+-Na(3s, 3p) collisions: I. Atomic basis coupled-channel calculations

International Nuclear Information System (INIS)

Nielsen, S.E.; Dubois, A.

1995-01-01

Integral cross sections for electron capture from the ground state Na(3s) and excited states Na(3p) to Li(nlm), n = 2, 3, are calculated by the semiclassical impact-parameter method, using a two-centre atomic basis expansion. In the impact energy range 1-50 keV, results are analysed with particular emphasis on the alignment and orientation of initial and final p-states. At intermediate velocities opposite initial alignment effects are found for capture to n = 2 and n = 3 states, respectively. Orientation effects in state-to-state capture cross sections are predicted from oriented and tilted aligned initial states. (Author)

Silicene for Na-ion battery applications

KAUST Repository

Zhu, Jiajie; Schwingenschlö gl, Udo

2016-01-01

Na-ion batteries are promising candidates to replace Li-ion batteries in large scale applications because of the advantages in natural abundance and cost of Na. Silicene has potential as the anode in Li-ion batteries but so far has not received

Synthesis and photoluminescence of Sm3+ doped alkali alkaline earth borate hosts NaBa4 (BO3)3 and LiSr4(BO3)3

International Nuclear Information System (INIS)

Chauhan, A.V.; Nagpure, P.A.; Omanwar, S.K.

2012-01-01

In this paper we report the photoluminescence of Sm 3+ doped alkali alkaline borate hosts NaBa 4 (BO 3 ) 3 and LiSr 4 (BO 3 ) 3 . For the synthesis of alkali alkaline borate hosts NaBa 4 (BO 3 ) 3 and LiSr 4 (BO 3 ) 3 doped with different concentrations of Sm 3+ ions, we used the novel combustion technique. The phase purity of the hosts was confirmed by the powder XRD technique. The photoluminescence of the phosphors were carried out within 300 to 700 nm wavelength range. The phosphor shows intense orange red (602 nm) emission for near UV excitation. The FTIR spectra of the phase pure hosts have also been reported. (author)

Versatile Coating of Lithium Conductive Li2TiF6 on Over-lithiated Layered Oxide in Lithium-Ion Batteries

International Nuclear Information System (INIS)

Choi, Wonchang; Benayard, Anass; Park, Jin-Hwan; Park, Junho; Doo, Seok-Gwang; Mun, Junyoung

2014-01-01

Highlights: • Li 2 TiF 6 coating was designed to grow surface lithium conductivity and stability. • We conducted an easy and versatile Li 2 TiF 6 lithium conductive coating on cathode. • The coating was performed very simply by ambient-temperature co-precipitation. • After the coating, rate capability, cycleability and thermal stability improved. - Abstract: We demonstrate an easy and versatile approach to modify a cathode-surface with a highly lithium–ion conductive layer by coating it with Li 2 TiF 6 . The thin and homogeneous Li 2 TiF 6 coating is introduced onto an over-lithiated layered oxide (OLO, namely Li 1.17 Ni 0.17 Co 0.1 Mn 0.56 O 2 ) surface via simple co-precipitation at ambient temperature by using Li 2 CO 3 and H 2 TiF 6 aqueous solutions. The lithium–conductive fluoride coating is expected to effectively suppress the undesired electrochemical and thermal interfacial reactions involving the OLO, which is critical in improving cycle performance and thermal stability. After Li 2 TiF 6 surface modification, the coated OLO materials showed high rate capability as well as long cyclability and improved thermal stability. The crystalline structure and surface microstructure of the prepared OLOs were investigated by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Ultimately, the performances of the assembled lithium ion batteries were thoroughly investigated by electrochemical methods and thermal analysis

Guided Lithium Metal Deposition and Improved Lithium Coulombic Efficiency through Synergistic Effects of LiAsF ₆ and Cyclic Carbonate Additives

Energy Technology Data Exchange (ETDEWEB)

Ren, Xiaodi [Energy; Zhang, Yaohui [Energy; Engelhard, Mark H. [Environmental; Li, Qiuyan [Energy; Zhang, Ji-Guang [Energy; Xu, Wu [Energy

2017-11-20

Spatial and morphology control over lithium (Li) metal nucleation/growth, as well as improving Li Coulombic efficiency (CE) are of the most challenging issues for rechargeable Li metal batteries. Here, we report that LiAsF6 and vinylene carbonate (VC) can work synergistically to address these challenges. It is revealed that AsF6- can be reduced to Li3As and LiF, which can act as seeds for Li growth and form a robust solid electrolyte interphase (SEI) layer, respectively. The addition of VC is critical because it not only enables uniform AsF6- reduction by passivating the defect sites on Cu substrate, but also improves the SEI layer flexibility during the reductive polymerization process. As a result, highly compact, uniform and dendrite-free Li film with vertically aligned columns structure can be obtained with greatly increased Li CE, and the Li metal batteries using the electrolyte with both LiAsF6 and VC additives can have much improved cycle life.

Integrated readout of organic scintillator and ZnS:Ag/6LiF for segmented antineutrino detectors

International Nuclear Information System (INIS)

Kiff, Scott D.; Reyna, David; Monahan, James; Bowden, Nathaniel S.

2010-01-01

Antineutrino detection using inverse beta decay conversion has demonstrated the capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which highly efficient capture and identification of neutrons is needed to measure the anticipated antineutrino event rates in an elevated background environment. In this submission, we report on initial characterization of a new scintillation-based segmented design that uses layers of ZnS:Ag/ 6 LiF and an integrated readout technique to capture and identify neutrons created in the inverse beta decay reaction. Laboratory studies with multiple organic scintillator and ZnS:Ag/ 6 LiF configurations reliably identify 6 Li neutron captures in 60 cm-long segments using pulse shape discrimination.

Low-Temperature Sintering Li3Mg1.8Ca0.2NbO6 Microwave Dielectric Ceramics with LMZBS Glass

Science.gov (United States)

Wang, Gang; Zhang, Huaiwu; Liu, Cheng; Su, Hua; Jia, Lijun; Li, Jie; Huang, Xin; Gan, Gongwen

2018-05-01

Li3Mg1.8Ca0.2NbO6 ceramics doped with Li2O-MgO-ZnO-B2O3-SiO2 glass (LMZBS) were prepared via a solid-state route. The LMZBS glass effectively reduced the sintering temperature of Li3Mg1.8Ca0.2NbO6 ceramics to 950°C. The effects of the LMZBS glass on the sintering behavior, microstructures and microwave dielectric properties of Li3Mg1.8Ca0.2NbO6 ceramics are discussed in detail. Among all the LMZBS doped Li3Mg1.8Ca0.2NbO6 ceramics, the sample with 1 wt.% of LMZBS glass sintered at 950°C for 4 h exhibited good dielectric properties: ɛ r = 16.7, Q × f = 31,000 GHz (9.92 GHz), τ f = - 1.3 ppm/°C. The Li3Mg1.8Ca0.2NbO6 ceramics possessed excellent chemical compatibility with Ag electrodes, and could be applied in low temperature co-fired ceramics (LTCC) applications.

Selectivity of crystalline Cesup(IV) phosphate sulphate hydrates for Li+, Na+, K+, Rb+ Cs+, and NH4+ in absolute methanol and absolute dimethylsulphoxide

International Nuclear Information System (INIS)

Koenig, K.H.; Psotta, L.

1978-01-01

The sequence of exchange capacities of Cerium(IV) phosphate sulphate hydrate (CePO 4 ) 2 (HPO 4 )sub(0.74(SO 4 )sub(0.26) . 4.74 H 2 O for alkalimetal ions and ammoniumions in absolute methanol at 25 0 C for the case of a small excess of the exchanger (in relation to the equivalent amount) is given by K + > Rb + >= NH 4 + > Cs + > Na + > Li + . Between the exchange capacity A of these cations and their ionic radii r (given by Ladd) exists the simple relation A = const./r. For Na + the radius of the inner hydration shell must be considered. In absolute dimethyl-sulphoxide under the same conditions the sequence is K + >= NH 4 + > Rb + > Na + > Cs + > Li + . For K + , NH 4 + , Rb + and Cs + the exchange capacity is given by A = const./r. + const. . r 4 . The sequences of the alkali ions in both solvents are among the group of 13 sequences which are physicaly significant according to Eisenmann's theory. The results are compared with the observations made with water as solvent. (author)

Fusion and nonfusion phenomena in the 6Li+40Ca reaction at 156 MeV

International Nuclear Information System (INIS)

Brzychczyk, J.; Freindl, L.; Grotowski, K.

1982-01-01

Reaction products from 6 Li-induced reactions on 40 Ca at 156 MeV have been studied using the dE x E identification as well as the inclusive γ-ray method. The complete fusion cross-section has been found to be σsub(f)=(77 +- 11)mb. The Z distribution of fusion evaporation residues is compared with statistical model predictions. The Z spectrum of reaction products shows a maximum at 15 6 Li break-up. (author)

Fusion and nonfusion phenomena in the 6Li+40Ca reaction at 156 MeV

International Nuclear Information System (INIS)

Brzychczyk, J.; Freindl, L.; Grotowski, K.; Majka, Z.; Micek, S.; Planeta, R.; Uniwersytet Jagiellonski, Krakow; Albinska, M.; Buschmann, J.; Klewe-Nebenius, H.; Gils, H.J.; Rebel, H.; Zagromski, S.

1984-01-01

Reaction products from 6 Li-induced reactions on 40 Ca at 156 MeV have been studied using the dExE idenitification as well as the inclusive γ-ray method. The complete fusion cross section has been found to be sigmasub(F)=67 +- 20 mb. The Z-distribution of fusion evaporation residues is compared with statistical model predictions. The Z-spectrum of reaction products shows a maximum at 15 6 Li-break-up processes. (orig.)

Lithiotantite, ideally LiTa3O8

Directory of Open Access Journals (Sweden)

Aba C. Persiano

2012-05-01

Full Text Available Lithiotantite (lithium tritantalum octaoxide and lithiowodginite are natural dimorphs of LiTa3O8, corresponding to the laboratory-synthesized L-LiTa3O8 (low-temperature form and M-LiTa3O8 (intermediate-temperature form phases, respectively. Based on single-crystal X-ray diffraction data, this study presents the first structure determination of lithiotantite from a new locality, the Murundu mine, Jenipapo District, Itinga, Minas Gerais, Brazil. Lithiotantite is isotypic with LiNb3O8 and its structure is composed of a slightly distorted hexagonal close-packed array of O atoms stacked in the [-101] direction, with the metal atoms occupying half of the octahedral sites. There are four symmetrically non-equivalent cation sites, with three of them occupied mainly by (Ta5+ + Nb5+ and one by Li+. The four distinct octahedra share edges, forming two types of zigzag chains (A and B extending along the b axis. The A chains are built exclusively of (Ta,NbO6 octahedra (M1 and M2, whereas the B chains consist of alternating (Ta,NbO6 and LiO6 octahedra (M3 and M4, respectively. The average M1—O, M2—O, M3—O and M4—O bond lengths are 2.011, 2.004, 1.984, and 2.188 Å, respectively. Among the four octahedra, M3 is the least distorted and M4 the most. The refined Ta contents at the M1, M2 and M3 sites are 0.641 (2, 0.665 (2, and 0.874 (2, respectively, indicating a strong preference of Ta5+ for M3 in the B chain. The refined composition of the crystal investigated is Li0.96Mn0.03Na0.01Nb0.82Ta2.18O8.

Hydrothermal synthesis of Li4-xNaxTi5O12 and Li4-xNaxTi5O12/graphene composites as anode materials for lithium-ion batteries

Directory of Open Access Journals (Sweden)

Zhu Jiping

2016-01-01

Full Text Available A potential Lithium-ion battery anode material Li4-xNaxTi5O12 (0≤x≤0.15 has been synthesized via a facile hydrothermal method with short processing time and low temperature. The XRD and FE-SEM results indicate that samples with Na-doped are well-crystallized and have more homogeneous particle distributions with smaller overall particle size in the range of 300-600nm. Electrochemical tests reveal that Na-doped samples exhibit impressive specific capacity and cycle stability compared to pristine Li4Ti5O12 at high rate. The Li3.9Na0.1Ti5O12 electrode deliver an initial specific discharge capacity of 169mAh/g at 0.5C and maintained at 150.4mAh/g even after 40 cycles with the reversible retention of 88.99%. Finally, a simple solvothermal reduction method was used to fabricate Li3.9Na0.1Ti5O12/graphene(Li3.9Na0.1Ti5O12/G composite. Galvanostatic charge-discharge tests demonstrate that this sample has remarkable capacities of 197.4mAh/g and 175.5mAh/g at 0.2C and 0.5C rate, respectively. This indicates that the Li3.9Na0.1Ti5O12/G composite is a promising anode material for using in lithium-ion batteries.

Mixed-Alkali Effect in Li2O-Na2O-K2O-B2O3 Glasses: Infrared and Optical Absorption Studies

Science.gov (United States)

Samee, M. A.; Edukondalu, A.; Ahmmad, Shaik Kareem; Taqiullah, Sair Md.; Rahman, Syed

2013-08-01

The mixed-alkali effect (MAE) has been investigated in the glass system (40 - x)Li2O- xNa2O-10K2O-50B2O3 (0 mol% ≤ x ≤ 40 mol%) through density, modulated differential scanning calorimetry (DSC), and optical absorption studies. From the absorption studies, the values of the optical band gap ( E opt) for direct transition and Urbach energy (Δ E) have been evaluated. The values of E opt and Δ E show nonlinear behavior with the compositional parameter. The density and glass-transition temperature of the present glasses also show nonlinear variation, supporting the existence of MAE. The infrared (IR) spectra of the glasses reveal the presence of three- and four-coordinated boron atoms. The specific vibrations of Li-O, Na-O, and K-O bonds were observed in the present IR study.

Structural phase transitions of NaV6O11 and SrV6O11

International Nuclear Information System (INIS)

Kanke, Yasushi; Izumi, Fujio; Kato, Katsuo; Morii, Yukio; Funahashi, Satoru; Akiba, Etsuo.

1993-01-01

Crystal structures of NaV 6 O 11 at several temperatures were studied by either Rietveld analyses of both neutron and X-ray powder diffraction data, or an analysis of X-ray single crystal diffraction data. At 200 K, NaV 6 O 11 loses the center of symmetry, and its space group changes from P6 3 /mmc to P6 3 mc. Consequently, V(2) splits into two sites. At 30 K, NaV 6 O 11 was transformed from the hexagonal form to the orthorhombic one (Cmc2 1 ), and V(1) splits into two sites. These results indicate that magnetic phase transitions of NaV 6 O 11 at 245 K and 64.2 K are accompanied by structural phase transitions. On the other hand, no structural phase transition was detected in SrV 6 O 11 . (author)

Na/K pump inactivation, subsarcolemmal Na measurements, and cytoplasmic ion turnover kinetics contradict restricted Na spaces in murine cardiac myocytes.

Science.gov (United States)

Lu, Fang-Min; Hilgemann, Donald W

2017-07-03

Decades ago, it was proposed that Na transport in cardiac myocytes is modulated by large changes in cytoplasmic Na concentration within restricted subsarcolemmal spaces. Here, we probe this hypothesis for Na/K pumps by generating constitutive transsarcolemmal Na flux with the Na channel opener veratridine in whole-cell patch-clamp recordings. Using 25 mM Na in the patch pipette, pump currents decay strongly during continuous activation by extracellular K (τ, ∼2 s). In contradiction to depletion hypotheses, the decay becomes stronger when pump currents are decreased by hyperpolarization. Na channel currents are nearly unchanged by pump activity in these conditions, and conversely, continuous Na currents up to 0.5 nA in magnitude have negligible effects on pump currents. These outcomes are even more pronounced using 50 mM Li as a cytoplasmic Na congener. Thus, the Na/K pump current decay reflects mostly an inactivation mechanism that immobilizes Na/K pump charge movements, not cytoplasmic Na depletion. When channel currents are increased beyond 1 nA, models with unrestricted subsarcolemmal diffusion accurately predict current decay (τ ∼15 s) and reversal potential shifts observed for Na, Li, and K currents through Na channels opened by veratridine, as well as for Na, K, Cs, Li, and Cl currents recorded in nystatin-permeabilized myocytes. Ion concentrations in the pipette tip (i.e., access conductance) track without appreciable delay the current changes caused by sarcolemmal ion flux. Importantly, cytoplasmic mixing volumes, calculated from current decay kinetics, increase and decrease as expected with osmolarity changes (τ >30 s). Na/K pump current run-down over 20 min reflects a failure of pumps to recover from inactivation. Simulations reveal that pump inactivation coupled with Na-activated recovery enhances the rapidity and effectivity of Na homeostasis in cardiac myocytes. In conclusion, an autoregulatory mechanism enhances cardiac Na/K pump activity when

AN UPDATED 6Li(p, α)3He REACTION RATE AT ASTROPHYSICAL ENERGIES WITH THE TROJAN HORSE METHOD

International Nuclear Information System (INIS)

Lamia, L.; Spitaleri, C.; Sergi, M. L.; Pizzone, R. G.; Tumino, A.; La Cognata, M.; Tognelli, E.; Degl'Innocenti, S.; Prada Moroni, P. G.; Pappalardo, L.

2013-01-01

The lithium problem influencing primordial and stellar nucleosynthesis is one of the most interesting unsolved issues in astrophysics. 6 Li is the most fragile of lithium's stable isotopes and is largely destroyed in most stars during the pre-main-sequence (PMS) phase. For these stars, the convective envelope easily reaches, at least at its bottom, the relatively low 6 Li ignition temperature. Thus, gaining an understanding of 6 Li depletion also gives hints about the extent of convective regions. For this reason, charged-particle-induced reactions in lithium have been the subject of several studies. Low-energy extrapolations of these studies provide information about both the zero-energy astrophysical S(E) factor and the electron screening potential, U e . Thanks to recent direct measurements, new estimates of the 6 Li(p, α) 3 He bare-nucleus S(E) factor and the corresponding U e value have been obtained by applying the Trojan Horse method to the 2 H( 6 Li, α 3 He)n reaction in quasi-free kinematics. The calculated reaction rate covers the temperature window 0.01 to 2T 9 and its impact on the surface lithium depletion in PMS models with different masses and metallicities has been evaluated in detail by adopting an updated version of the FRANEC evolutionary code.

Magnetic measurements of superconducting LiFeAs single crystals under high pressure

Science.gov (United States)

Miyoshi, Kiyotaka; Otsuka, Keisuke; Ogawa, Saki; Takeuchi, Jun

2018-05-01

Measurements of DC magnetization for single crystal specimens of LiFeAs have been performed under pressure using liquid argon and NaCl as pressure transmitting media (PTM) to generate hydrostatic and nearly uniaxial pressure along c-axis, respectively. It has been found that Tc linearly decreases under pressure with pressure coefficient dTc / dP ∼ - 1.6 - 1.7 K/GPa, and then shows a pressure independent behavior with Tc ∼ 8 K above 5 GPa. These behaviors are observed independently of whether we select liquid argon or NaCl as PTM. This suggests that c-axis lattice constant is not an important factor to determine Tc in LiFeAs, in contrast to KxFe2-ySe2 and (NH3)yAxFe2Se2 (A=alkali metal).

Effects of Li and Na intercalation on electronic, bonding and thermoelectric transport properties of MX{sub 2} (M = Ta; X = S or Se) dichalcogenides – Ab initio investigation

Energy Technology Data Exchange (ETDEWEB)

Meziane, Souheyr; Feraoun, Houda [Unité de Recherche Matériaux et Energies Renouvelables – URMER, Université de Tlemcen (Algeria); Ouahrani, Tarik [Laboratoire de Physique Théorique, Ecole Préparatoire en Sciences et Techniques, B.P. 230, 13000 Tlemcen (Algeria); Esling, Claude, E-mail: claude.esling@univ-lorraine.fr [Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux, LEM3 UMR CNRS 7239, Université de Lorraine UL, Metz 57045 (France); Laboratoire d’Excellence “DAMAS”: Design of Metal Alloys for low-mAss Structures, Université de Lorraine – Metz, Ile du Saulcy, 57045 Metz Cedex 01 (France)

2013-12-25

Highlights: •Topological method is used to analyze the chemical bonding in Li(Na)TaX{sub 2} dichalcogenide compounds. •For the first time, Seebeck coefficient, electrical resistivity and thermal conductivity were estimated. •The best figure of merit is established for 2H-LiTaS{sub 2}. •Some new thermoelectric compounds are found. -- Abstract: Using the pseudo-potential method and semi-classical Boltzmann theory, electronic, chemical bonding and thermoelectric transport properties of sample and Li or Na intercalated Ta(S, Se){sub 2} dichalcogenides have been reported. The chemical bonding is studied using the Quantum Theory of Atoms in Molecules (QTAIM). Then, the Seebeck coefficient, electrical resistivity, electrical conductivity, thermal conductivity and figure of merit have been calculated in the temperature range 100–700 K. It was shown that the thermoelectric transport properties strongly depend on the Alkali metals doping and the two main structures 1T- or 2H- as well as the temperature. 2H-LiTaS{sub 2} have been selected as the best candidate for thermoelectrical applications with zT = 1.1.

Effect of MnO doping on the structure, microstructure and electrical properties of the (K,Na,Li)(Nb,Ta,Sb)O{sub 3} lead-free piezoceramics

Energy Technology Data Exchange (ETDEWEB)

Rubio-Marcos, F., E-mail: fernando.rubio-marcos@unilim.fr [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Marchet, P. [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Vendrell, X. [Grup de Quimica de l' Estat Solid, Departament de Quimica Inorganica, Universitat de Barcelona, 08028 Barcelona (Spain); Romero, J.J. [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Remondiere, F. [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Mestres, L. [Grup de Quimica de l' Estat Solid, Departament de Quimica Inorganica, Universitat de Barcelona, 08028 Barcelona (Spain); Fernandez, J.F. [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain)

2011-09-01

Highlights: {center_dot} MnO doping effects on structure and properties of (K,Na,Li)(Nb,Ta,Sb)O{sub 3} piezoceramics. {center_dot} The structure changes towards an orthorhombic symmetry for higher MnO concentrations. {center_dot} High doping levels induce a tetragonal tungsten-bronze secondary phase. {center_dot} Mn{sup 2+} doping modifies the phase transition temperature and the piezoelectric properties. {center_dot} Manganese doping increases the mechanical quality factor Q{sub m}. - Abstract: Mn{sup 2+}-doped (K,Na,Li)(Nb,Ta,Sb)O{sub 3} lead-free piezoelectric ceramics have been prepared by a conventional sintering technique. The effects of Mn{sup 2+} doping on the phase structure, microstructure and ferro-piezoelectric properties of the ceramics have been evaluated. MnO doping modifies the (K,Na,Li)(Nb,Ta,Sb)O{sub 3} structure, giving rise to the appearance of a TTB-like secondary phase and to changes on the orthorhombic to tetragonal phase transition temperature. The modification of this temperature induces a reduction of the piezoelectric constants, which is accompanied by an increase on the mechanical quality factor. Mn{sup 2+} ions incorporate into the perovskite structure in different off ways depending on their concentration.

Measurements of double-differential neutron emission cross sections of {sup 6}Li and {sup 7}Li for 18 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Ibaraki, Masanobu; Baba, Mamoru; Matsuyama, Shigeo; Sanami, Toshiya; Win, T.; Miura, Takako; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

1997-03-01

Double-differential neutron emission cross sections of {sup 6}Li and {sup 7}Li were measured for 18 MeV neutrons at Tohoku University 4.5 MV Dynamitron facility. Neutron emission spectra were obtained down to 1 MeV at 13 angles with energy resolution good enough to separate discrete levels. A care was taken to eliminate the sample-dependent background due to parasitic neutrons. Experimental results were in fair agreement with the JENDL-3.2 data and a simple model considering a three-body breakup process and discrete level excitations. (author)

Hydrothermal synthesis, structures and optical properties of A2Zn3(SeO3)4·XH2O (A=Li, Na, K; X=2 or 0)

Science.gov (United States)

Liu, Yunsheng; Mei, Dajiang; Xu, Jingli; Wu, Yuandong

2015-12-01

New alkali metal zinc selenites, A2Zn3(SeO3)4·XH2O (A=Li, Na, K; X=2 or 0) were prepared through hydrothermal reactions. Li2Zn3(SeO3)4·2H2O (1) crystallizes in the monoclinic space group P21/c with lattice parameters a=8.123(4), b=9.139(4), c=7.938(3) Å, β=112.838(9)°. Na2Zn3(SeO3)4·2H2O (2) crystallizes in the monoclinic space group C2/c with lattice parameters a=15.7940(18), b=6.5744(8), c=14.6787(17) Å, β=107.396(3)°. K2Zn3(SeO3)4 (3) crystallizes in the monoclinic space group C2/c with lattice parameters a=11.3584(12), b=8.6091(9), c=13.6816(14) Å, β=93.456(2)°. The anionic structures are composed of [Zn3O12]18- sheets, chains, and "isolated" units in compound 1, 2, 3, respectively, and trigonal pyramids SeO32-. The compounds were characterized by the solid state UV-vis-NIR diffuse reflectance spectroscopy, infrared spectra and thermogravimetric analysis.

The dehydrogenation performance and reaction mechanisms of Li{sub 3}AlH{sub 6} with TiF{sub 3} additive

Energy Technology Data Exchange (ETDEWEB)

Liu, Shu-Sheng [Materials and Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yao; Sun, Li-Xian; Zhang, Jian; Zhao, Jun-Ning [Materials and Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Xu, Fen [Faculty of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Huang, Feng-Lei [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

2010-05-15

For Li{sub 3}AlH{sub 6} prepared by mechanical milling method, the dissociation reaction enthalpy and activation energy are calculated to be 22.1 kJ mol{sup -1} H{sub 2} and 133.7 {+-} 2.7 kJ mol{sup -1}, respectively. The dehydrogenation performance of Li{sub 3}AlH{sub 6} is greatly enhanced by TiF{sub 3} additive, especially in the kinetic behaviors. For the Li{sub 3}AlH{sub 6} + 10 mol% TiF{sub 3} sample, the starting temperature of dehydrogenation is obviously decreased by 60 C from that of pure Li{sub 3}AlH{sub 6} (190 C), and 3.0 wt.% H{sub 2} may be released within 1000 s at 120 C under an initial vacuum. With the amount of TiF{sub 3} increasing, the starting temperature decreases and the kinetics improves due to the decrease in the activation energy. The X-ray diffraction (XRD) together with thermogravimetric analysis (TGA) results show that there are three mechanochemical reactions involved during milling: i) Li{sub 3}AlH{sub 6} + TiF{sub 3} {yields} 3 LiF + Al + Ti + 3H{sub 2}, ii) Ti + H{sub 2} {yields} TiH{sub 2}, iii) 3 Al + Ti {yields} Al{sub 3}Ti. The in-situ formed Ti species (TiH{sub 2} and Al{sub 3}Ti) co-catalyze the thermal dehydrogenation of Li{sub 3}AlH{sub 6}. (author)

Depth profiling Li in electrode materials of lithium ion battery by {sup 7}Li(p,γ){sup 8}Be and {sup 7}Li(p,α){sup 4}He nuclear reactions

Energy Technology Data Exchange (ETDEWEB)

Sunitha, Y., E-mail: sunibarc@gmail.com; Kumar, Sanjiv

2017-06-01

A proton induced γ-ray emission method based on {sup 7}Li(p,γ){sup 8}Be proton capture reaction and a nuclear reaction analysis method involving {sup 7}Li(p,α){sup 4}He reaction are described for depth profiling Li in the electrode materials, graphite and lithium cobalt oxide for example, of a Li-ion battery. Depth profiling by {sup 7}Li(p,γ){sup 8}Be reaction is accomplished by the resonance at 441 keV and involves the measurement of 14.6 and 17.6 MeV γ-rays, characteristic of the reaction, by a NaI(Tl) detector. The method has a detection sensitivity of ∼0.2 at% and enables profiling up to a depth ≥20 µm with a resolution of ≥150 nm. The profiling to a fairly large depth is facilitated by the absence of any other resonance up to 1800 keV proton energy. The reaction has substantial off-resonance cross-sections. A procedure is outlined for evaluating the off-resonance yields. Interferences from fluorine and aluminium are major limitation of this depth profiling methodology. The depth profile measurement by {sup 7}Li(p,α){sup 4}He reaction, on the other hand, utilises 2–3 MeV protons and entails the detection of α-particles at 90° or 150° angles. The reaction exhibits inverse kinematics at 150°. This method, too, suffers interference from fluorine due to the simultaneous occurrence of {sup 19}F(p,α){sup 16}O reaction. Kinematical considerations show that the interference is minimal at 90° and thus is the recommended angle of detection. The method is endowed with a detection sensitivity of ∼0.1 at%, a depth resolution of ∼100 nm and a probing depth of about 30 µm in the absence and 5–8 µm in the presence of fluorine in the material. Both methods yielded comparable depth profiles of Li in the cathode (lithium cobalt oxide) and the anode (graphite) of a Li-ion battery.

Tug of war between AO-hybridization and aromaticity in dictating structures of Li-doped alkali clusters

Science.gov (United States)

Alexandrova, Anastassia N.

2012-04-01

Hybridization of atomic orbitals is a widely appreciated phenomenon in organic chemistry. Here, we demonstrate that hybridization also can dramatically impact the shapes of small all-alkali metal clusters, and oppose σ-aromaticity in defining cluster shapes. The valence-iso-electronic LiNa4- and LiK4- clusters adopt different global minimum structures: LiNa4- is a planar C2v (1A1) species distorted from the perfect pentagon, and LiK4- is a planar square D4h (1A1g) species with Li being in the centre. This effect is rooted in the different degrees of the 2s-2p hybridization in Li in response to binding to Na versus K.

Selectivity of crystalline Ce(IV)-phosphate-sulphate hydrates for Li+, Na+, K+, Rb+, Cs+, and NH4+ in aqueous medium

International Nuclear Information System (INIS)

Koenig, K.H.; Psotta, L.

1978-01-01

The sequence of exchange-capacities of Cerium(IV)-phosphate-sulphate hydrate (CePO 4 ) 2 (HPO 4 )sub(0.74)(SO 4 )sub(0.26) . 4.74 H 2 O concerning the alkaline ions and the ammonium ion in water at 25 0 C for the case of a small excess of the exchanger (in relation to the equivalent amount) is given by Na + > K + > Rb + > NH 4 + > Cs + > Li + . The simple relation A const/r was found between the exchange-capacity A of these cations and their ionic radii r (given by Ladd); only for Li + the radius of the inner hydration-shell must be considered. The observations are consistent with Eisenmann's theory. (author)

Thermodynamic assessment of the LiF–NaF–BeF{sub 2}–ThF{sub 4}–UF{sub 4} system

Energy Technology Data Exchange (ETDEWEB)

Capelli, E.; Beneš, O., E-mail: ondrej.benes@ec.europa.eu; Konings, R.J.M.

2014-06-01

The present study describes the full thermodynamic assessment of the LiF–NaF–BeF{sub 2}–ThF{sub 4}–UF{sub 4} system which is one of the key systems considered for a molten salt reactor fuel. The work is an extension of the previously assessed LiF–NaF–ThF{sub 4}–UF{sub 4} system with addition of BeF{sub 2} which is characterized by very low neutron capture cross section and a relatively low melting point. To extend the database the binary BeF{sub 2}–ThF{sub 4} and BeF{sub 2}–UF{sub 4} systems were optimized and the novel data were used for the thermodynamic assessment of BeF{sub 2} containing ternary systems for which experimental data exist in the literature. The obtained database is used to optimize the molten salt reactor fuel composition and to assess its properties with the emphasis on the melting behaviour.

Premelting, Melting, and Degradation Properties of Molten Alkali Nitrates: LiNO3, NaNO3, KNO3, and Binary NaNO3-KNO3

Science.gov (United States)

Mohammad, Mehedi Bin; Brooks, Geoffrey Alan; Rhamdhani, Muhammad Akbar

2018-02-01

A simultaneous thermal analyzer (STA) was used to observe the transition and degradation events of LiNO3, NaNO3, KNO3, and binary NaNO3-KNO3 salts for potential use as phase change materials (PCMs) and heat transfer fluid (HTF). Samples were heated from 50 °C to 800 °C at 10 °C/min scanning rate in three atmospheres (argon, air, and oxygen) using an STA to observe decomposition behavior. Thermal stability increased for all salts at high partial pressure of O2 ( P_{{{O}2 }} = 1.0) compared to inert argon ( P_{{{O}2 }} = 0). O2, N2, NO, N2O, and NO2 were main evolved gases during nitrate decomposition. NO and O2 started to evolve at approximately the same temperature after melting, indicating that primary and secondary decomposition reactions were concurrent and overlapping. The solid-solid transition, liquidus and solidus temperatures, heat of transition, heat of melting, and heat of solidification were obtained at various heating-cooling rates (1, 2, 4, 5, 6, 8, 10, and 15 °C/min) using an STA. At all heating-cooling rates, a small gap exists between liquidus and solidus temperatures for all samples due to the salts exhibiting supercooling phenomena. This study showed that the degradation point depends on the blanket atmosphere top of the molten salts and that heating rates have a minor effect on transition events (peaks height, peaks width, and transition enthalpies).

Premelting, Melting, and Degradation Properties of Molten Alkali Nitrates: LiNO3, NaNO3, KNO3, and Binary NaNO3-KNO3

Science.gov (United States)

Mohammad, Mehedi Bin; Brooks, Geoffrey Alan; Rhamdhani, Muhammad Akbar

2018-06-01

A simultaneous thermal analyzer (STA) was used to observe the transition and degradation events of LiNO3, NaNO3, KNO3, and binary NaNO3-KNO3 salts for potential use as phase change materials (PCMs) and heat transfer fluid (HTF). Samples were heated from 50 °C to 800 °C at 10 °C/min scanning rate in three atmospheres (argon, air, and oxygen) using an STA to observe decomposition behavior. Thermal stability increased for all salts at high partial pressure of O2 ( P_{{{O}2 }} = 1.0) compared to inert argon ( P_{{{O}2 }} = 0). O2, N2, NO, N2O, and NO2 were main evolved gases during nitrate decomposition. NO and O2 started to evolve at approximately the same temperature after melting, indicating that primary and secondary decomposition reactions were concurrent and overlapping. The solid-solid transition, liquidus and solidus temperatures, heat of transition, heat of melting, and heat of solidification were obtained at various heating-cooling rates (1, 2, 4, 5, 6, 8, 10, and 15 °C/min) using an STA. At all heating-cooling rates, a small gap exists between liquidus and solidus temperatures for all samples due to the salts exhibiting supercooling phenomena. This study showed that the degradation point depends on the blanket atmosphere top of the molten salts and that heating rates have a minor effect on transition events (peaks height, peaks width, and transition enthalpies).

A Ge(Li)-NaI(Tl) Compton-suppression spectrometer for in-beam γ-ray spectroscopy, ch. 2

International Nuclear Information System (INIS)

Driel, M.A. van; Hoogenboom, A.M.

1976-01-01

A Compton-suppression spectrometer has been constructed for in-beam γ-ray work. It consists of a closed-end Ge(Li) detector with an efficiency of 21% and a resolution of 2.0 keV for 1.33 MeV γ-rays surrounded by a NaI(Tl) shield (dia. 230 mm, length 280 mm). The overall Compton-suppression factor for a 60 Co spectrum is 10. Details of the construction are discussed and experimental properties are compared with design calculations

Study on Stability and Electrochemical Properties of Nano-LiMn1.9Ni0.1O3.99S0.01-Based Li-Ion Batteries with Liquid Electrolyte Containing LiPF6

Directory of Open Access Journals (Sweden)

Monika Bakierska

2016-01-01

Full Text Available Herein, we report on the stability and electrochemical properties of nanosized Ni and S doped lithium manganese oxide spinel (LiMn1.9Ni0.1O3.99S0.01, LMN1OS in relation to the most commonly used electrolyte solution containing LiPF6 salt. The influence of electrochemical reaction in the presence of selected electrolyte on the LMN1OS electrode chemistry was examined. The changes in the structure, surface morphology, and composition of the LMN1OS cathode after 30 cycles of galvanostatic charging/discharging were determined. In addition, thermal stability and reactivity of the LMN1OS material towards the electrolyte system were verified. Performed studies revealed that no degradative effects, resulting from the interaction between the spinel electrode and liquid electrolyte, occur during electrochemical cycling. The LMN1OS electrode versus LiPF6-based electrolyte has been indicated as an efficient and electrochemically stable system, exhibiting high capacity, good rate capability, and excellent coulombic efficiency. The improved stability and electrochemical performance of the LMN1OS cathode material originate from the synergetic substitution of LiMn2O4 spinel with Ni and S.

Complete and incomplete fusion dynamics of {sup 6,7}Li + {sup 159}Tb reactions near the Coulomb barrier

Energy Technology Data Exchange (ETDEWEB)

Gautam, Manjeet Singh [Thapar University, School of Physics and Materials Science, Patiala (India); Indus Degree College, Department of Physics, Kinana, Jind, Haryana (India); Grover, Neha; Sharma, Manoj K. [Thapar University, School of Physics and Materials Science, Patiala (India)

2017-01-15

The complete fusion (CF) and incomplete fusion (ICF) cross-sections are estimated for {sup 6,} {sup 7}Li + {sup 159}Tb reactions using the energy-dependent Woods-Saxon potential model (EDWSP model) and dynamical cluster-decay model (DCM). The CF data of the {sup 6}Li + {sup 159}Tb({sup 7}Li + {sup 159}Tb) reaction at above barrier energies is suppressed with reference to expectations of the EDWSP model by 25% (20%) which is smaller than the reported data by ∝ 9% (6%). This suppression is correlated with the projectile breakup effect. The projectiles {sup 6,7}Li are loosely bound systems, which may break up into charged fragments prior to reaching the fusion barrier and subsequently one of the fragment is captured by the target leading to the suppression of fusion data at above barrier energies. The sum of CF and ICF, which is termed as total fusion cross-section (TF), removes the discrepancies between theoretical predictions and the above barrier complete fusion data and hence is adequately explained via the EDWSP model over a wide range of energy spread across the Coulomb barrier. In addition to fusion, the decay mechanism of {sup 6}Li + {sup 159}Tb reaction is studied within the framework of the dynamical cluster-decay model (DCM). The breakup of the projectile ({sup 6}Li) in the entrance channel indicates the presence of ICF, which is investigated further using the collective clusterization approach of DCM. The present theoretical analysis suggests that a larger barrier modification is needed to address the fusion data of chosen reactions in the below barrier energy region. (orig.)

Subnitride chemistry: A first-principles study of the NaBa3N, Na5Ba3N, and Na16Ba6N phases

International Nuclear Information System (INIS)

Oliva, Josep M.

2005-01-01

An ab initio study on the electronic structure of the subnitrides NaBa 3 N, Na 5 Ba 3 N, and Na 16 Ba 6 N is performed for the first time. The NaBa 3 N and Na 5 Ba 3 N phases consist of infinite 1 ∞ [NBa 6/2 ] strands composed of face-sharing NBa 6 octahedra surrounded by a 'sea' of sodium atoms. The Na 16 Ba 6 N phase consist of discrete [NBa 6 ] octahedra arranged in a body-cubic fashion, surrounded by a 'sea' of sodium atoms. Our calculations suggest that the title subnitrides are metals. Analysis of the electronic structure shows partial interaction of N(2s) with Ba(5p) electrons in the lower energy region for NaBa 3 N and Na 5 Ba 3 N. However, no dispersion is observed for the N(2s) and Ba(5p) bands in the cubic phase Na 16 Ba 6 N. The metallic band below the Fermi level shows a strong mixing of N(2p), Ba(6s), Ba(5d), Ba(6p), Na(3s) and Na(3p) orbitals. The metallic character in these nitrides stems from delocalized electrons corresponding to hybridized 5d l 6s m 6p n barium orbitals which interact with hybridized 3s n 3p m sodium orbitals. Analysis of the electron density and electronic structure in these nitrides shows two different regions: a metallic matrix corresponding to the sodium atoms and the regions around them and heteropolar bonding between nitrogen and barium within the infinite 1 ∞ [NBa 6/2 ] strands of the NaBa 3 N and Na 5 Ba 3 N phases, and within the isolated [NBa 6 ] octahedra of the Na 16 Ba 6 N phase. The nitrogen atoms inside the strands and octahedra are negatively charged, the anionic character of nitrogens being larger in the isolated octahedra of the cubic phase Na 16 Ba 6 N, due to the lack of electron delocalization along one direction as opposed to the other phases. The sodium and barium atoms appear to be slightly negatively and positively charged, the latter to a larger extent. From the computed Ba-N overlap populations as well as the analysis of the contour maps of differences between total density and superposition of

MeB5O8(Me-Li, Na, K, NH4)-H2NCONHCOCH3-H2O system at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Fedorov, Yu.A.; Molodkin, A.K.; Tsekhanskij, R.S.

1986-01-01

Using the methods of isothermal solubility, densi- and refractometry, systems MB 5 O 8 (M-Li, Na, K, NH 4 )-acetylcarbamide - H 2 O at 25 deg C have been studied. It is ascertained, that the systems investigated are of simple eutonic type

Thermodynamic assessment of the LiF-NaF-ThF4-UF4 system

International Nuclear Information System (INIS)

Benes, O.; Beilmann, M.; Konings, R.J.M.

2010-01-01

A thermodynamic assessment of the LiF-NaF-ThF 4 -UF 4 system is presented in this study. The binary phase diagrams are optimized based on the known experimental data and the excess Gibbs energies of liquid and solid solutions are described using a modified quasi chemical model and polynomial formalism respectively. The higher order systems are extrapolated according to asymmetric Toop mathematical formalism. Based on the developed thermodynamic database the fuel composition of the molten salt fast reactor is optimized. In total three different fuel compositions are identified. Properties of these fuel compositions such as melting point, vapour pressure and the boiling temperature are derived from the obtained thermodynamic assessment and are presented in this study.

Lattice dynamics of cubic Cs2NaLnX6 and CsNaLn1-xLn'xX6 elpasolites

International Nuclear Information System (INIS)

Acevedo, R.; Poblete, V.; Alzamora, R.; Venegas, R.; Navarro, G.; Henriquez, C.

1999-01-01

Crystal lattice dynamics of stoichiometric Cs 2 NaLnX 6 and nonstoichiometric CsNaLn 1-x Ln' x X 6 , 0.01 ≤ x ≤ 0.10, Ln and Ln' are trivalent positive lanthanide ions and X is chlorine or bromine, were studied.. Phonon dispersion relations were computed for similar compound, Cs 2 UBr 6 , and vibronic absorption spectra with reduced number of required input parameters are considered on the basis of proposed model. (author)

Scintillation properties of LiF–SrF2 and LiF–CaF2 eutectic

International Nuclear Information System (INIS)

Yanagida, Takayuki; Kawaguchi, Noriaki; Fujimoto, Yutaka; Fukuda, Kentaro; Watanabe, Kenichi; Yamazaki, Atsushi; Uritani, Akira

2013-01-01

Dopant free eutectic scintillators 6 LiF–SrF 2 and 6 LiF–CaF 2 were developed by the vertical Bridgeman method for the purpose of thermal neutron detection. The molar ratio of LiF and Ca/SrF 2 was 4:1 on its eutectic composition. The α-ray induced radioluminescence spectra of the scintillators showed intense emission peak at 300 nm due to the emission from the self-trapped exciton in Ca/SrF 2 layers. When the samples were irradiated with 252 Cf neutrons, 6 LiF–SrF 2 and 6 LiF–CaF 2 exhibited the light yields of 4700 and 9400 ph/n, respectively. Scintillation decay times of 6 LiF–SrF 2 and 6 LiF–CaF 2 were accepted for scintillation detectors, 90 and 250 ns, respectively. -- Highlights: • Nondoped LiF–CaF 2 and LiF–SrF 2 eutectic scinitillators are reported for the first time. • Two sample showed self-trapped exciton emission. • LiF–SrF 2 sample exhibited the light yield of 9400 ph/n and this value was comparable to conventional materials doped with rare earth ions. • Scintillation decay times of LiF–CaF 2 and LiF–SrF 2 were 250 and 90 ns, respectively

Shock equation of state of 6LiH to 1.1 TPa

Science.gov (United States)

Lazicki, A.; London, R. A.; Coppari, F.; Erskine, D.; Whitley, H. D.; Caspersen, K. J.; Fratanduono, D. E.; Morales, M. A.; Celliers, P. M.; Eggert, J. H.; Millot, M.; Swift, D. C.; Collins, G. W.; Kucheyev, S. O.; Castor, J. I.; Nilsen, J.

2017-10-01

Using laser-generated shock waves, we have measured pressure, density, and temperature of LiH on the principal Hugoniot between 260 and 1100 GPa (2.6-11 Mbar) and on a second-shock Hugoniot up to 1400 GPa to near fivefold compression, extending the maximum pressure reached in non-nuclear experiments by a factor of two. We observe the onset of metal-like reflectivity consistent with temperature-induced ionization of the Li 2s electron, and no sign of additional changes in ionization up to the maximum pressure. Our measurements are in good agreement with gas gun, Z-machine, and underground test data and are accurately described by quantum molecular dynamics simulations. The results confirm the validity of equation of state models built on an average-atom description of the electron-thermal contribution to the free energy and a density-dependent Grüneisen parameter to describe shock response of LiH over this pressure range.

Synthesis and electrochemistry of cubic rocksalt Li-Ni-Ti-O compounds in the phase diagram of LiNiO{sub 2}-LiTiO{sub 2}-Li[Li{sub 1/3}Ti{sub 2/3}]O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lianqi; Noguchi, Hideyuki; Li, Decheng; Muta, Takahisa; Wang, Xiaoqing; Yoshio, Masaki [Department of Applied Chemistry, Saga University, Saga 840-8052 (Japan); Taniguchi, Izumi [Department of Chemical Engineering, Tokyo Institute of Technology, 12-1, Ookayama-2, Meguro-ku, Tokyo 152-8552 (Japan)

2008-10-15

On the basis of extreme similarity between the triangle phase diagrams of LiNiO{sub 2}-LiTiO{sub 2}-Li[Li{sub 1/3}Ti{sub 2/3}]O{sub 2} and LiNiO{sub 2}-LiMnO{sub 2}-Li[Li{sub 1/3}Mn{sub 2/3}]O{sub 2}, new Li-Ni-Ti-O series with a nominal composition of Li{sub 1+z/3}Ni{sub 1/2-z/2}Ti{sub 1/2+z/6}O{sub 2} (0 {<=} z {<=} 0.5) was designed and attempted to prepare via a spray-drying method. XRD identified that new Li-Ni-Ti-O compounds had cubic rocksalt structure, in which Li, Ni and Ti were evenly distributed on the octahedral sites in cubic closely packed lattice of oxygen ions. They can be considered as the solid solution between cubic LiNi{sub 1/2}Ti{sub 1/2}O{sub 2} and Li[Li{sub 1/3}Ti{sub 2/3}]O{sub 2} (high temperature form). Charge-discharge tests showed that Li-Ni-Ti-O compounds with appropriate compositions could display a considerable capacity (more than 80 mAh g{sup -1} for 0.2 {<=} z {<=} 0.27) at room temperature in the voltage range of 4.5-2.5 V and good electrochemical properties within respect to capacity (more than 150 mAh g{sup -1} for 0 {<=} z {<=} 0.27), cycleability and rate capability at an elevated temperature of 50 C. These suggest that the disordered cubic structure in some cases may function as a good host structure for intercalation/deintercalation of Li{sup +}. A preliminary electrochemical comparison between Li{sub 1+z/3}Ni{sub 1/2-z/2}Ti{sub 1/2+z/6}O{sub 2} (0 {<=} z {<=} 0.5) and Li{sub 6/5}Ni{sub 2/5}Ti{sub 2/5}O{sub 2} indicated that charge-discharge mechanism based on Ni redox at the voltage of >3.0 V behaved somewhat differently, that is, Ni could be reduced to +2 in Li{sub 1+z/3}Ni{sub 1/2-z/2}Ti{sub 1/2+z/6}O{sub 2} while +3 in Li{sub 6/5}Ni{sub 2/5}Ti{sub 2/5}O{sub 2}. Reduction of Ti{sup 4+} at a plateau of around 2.3 V could be clearly detected in Li{sub 1+z/3}Ni{sub 1/2-z/2}Ti{sub 1/2+z/6}O{sub 2} with 0.27 {<=} z {<=} 0.5 at 50 C after a deep charge associated with charge compensation from oxygen ion during initial cycle

Rate theory of solvent exchange and kinetics of Li(+) - BF4 (-)/PF6 (-) ion pairs in acetonitrile.

Science.gov (United States)

Dang, Liem X; Chang, Tsun-Mei

2016-09-07

In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li(+) and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li(+) in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li(+)-[BF4] and Li(+)-[PF6] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li(+). We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li(+)-[BF4] and Li(+)-[PF6] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.

Electronic structure and optical properties of noncentrosymmetric LiGaGe{sub 2}Se{sub 6}, a promising nonlinear optical material

Energy Technology Data Exchange (ETDEWEB)

Lavrentyev, A.A.; Gabrelian, B.V.; Vu, V.T.; Ananchenko, L.N. [Department of Electrical Engineering and Electronics, Don State Technical University, 1 Gagarin Square, 344010 Rostov-on-Don (Russian Federation); Isaenko, L.I. [Laboratory of Crystal Growth, Institute of Geology and Mineralogy, SB RAS, 43 Russkaya Street, 630090 Novosibirsk (Russian Federation); Laboratory of Semiconductor and Dielectric Materials, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk (Russian Federation); Yelisseyev, A.; Krinitsin, P.G. [Laboratory of Crystal Growth, Institute of Geology and Mineralogy, SB RAS, 43 Russkaya Street, 630090 Novosibirsk (Russian Federation); Khyzhun, O.Y., E-mail: khyzhun@ipms.kiev.ua [Frantsevych Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhyzhanivsky Street, UA-03142 Kyiv (Ukraine)

2016-11-15

X-ray photoelectron core-level and valence-band spectra are measured for pristine and Ar{sup +} ion-bombarded surfaces of LiGaGe{sub 2}Se{sub 6} single crystal grown by Bridgman-Stockbarger technique. Further, electronic structure of LiGaGe{sub 2}Se{sub 6} is elucidated from both theoretical and experimental viewpoints. Density functional theory (DFT) calculations are made using the augmented plane wave +local orbitals (APW+lo) method to study total and partial densities of states in the LiGaGe{sub 2}Se{sub 6} compound. The present calculations indicate that the principal contributors to the valence band are the Se 4p states: they contribute mainly at the top and in the central portion of the valence band of LiGaGe{sub 2}Se{sub 6}, with also their significant contributions in its lower portion. The Ge 4s and Ge 4p states are among other significant contributors to the valence band of LiGaGe{sub 2}Se{sub 6}, contributing mainly at the bottom and in the central portion, respectively. In addition, the calculations indicate that the bottom of the conduction band is composed mainly from the unoccupied Ge s and Se p states. The present DFT calculations are supported experimentally by comparison on a common energy scale of the X-ray emission bands representing the energy distribution of the 4p states associated with Ga, Ge and Se and the XPS valence-band spectrum of the LiGaGe{sub 2}Se{sub 6} single crystal. The main optical characteristics of the LiGaGe{sub 2}Se{sub 6} compound are elucidated by the first-principles calculations.

Increase of ionic conductivity in the microporous lithosilicate RUB-29 by Na-ion exchange processes

International Nuclear Information System (INIS)

Park, S.-H.; Senyshyn, A.; Paulmann, C.

2007-01-01

The ionic conductivity in the zeolite-like lithosilicate RUB-29 (Cs 14 Li 24 [Li 18 Si 72 O 172 ].14H 2 O [S.-H. Park, J.B. Parise, H. Gies, H. Liu, C.P. Grey, B.H. Toby, J. Am. Chem. Soc. 122 (2000) 11023-11024]) increases via simple ion-exchange processes, in particular when Na cations replace a part of Cs + and Li + of the material. The resulting ionic conductivity value of 3.2x10 -3 S cm -1 at 885 K is about two orders higher than that for the original material [S.-H. Park, J.B. Parise, M.E. Franke, T. Seydel, C. Paulmann, Micropor. Mesopor. Mater., in print ( (doi:10.1016/j.micromeso.2007.03.040) available online since April 19, 2007)]. The structural basis of a Na + -exchanged RUB-29 sample (Na-RUB-29) at 673 K could be elucidated by means of neutron powder diffraction. Rietveld refinements confirmed the replacement of Na + for both parts of Cs and Li cations, agreeing with idealized cell content, Na 8 Cs 8 Li 40 Si 72 O 172 . As a result of the incorporation of Na + in large pores, the number of Li + vacancies in dense Li 2 O-layers of the structure could increase. This can be one of the main reasons for the improved conductivity in Na-RUB-29. In addition, mobile Na cations may also contribute to the conductivity in Na-RUB-29 as continuous scattering length densities were found around the sites for Na in difference Fourier map. - Graphical abstract: Li 2 O-layers formed by edge- and corner-sharing LiO 4 - and LiO 3 -moieties in the zeolite-like lithosilicate RUB-29 provide optimal pathways for conducting Li + . The number of empty Li sites in this layer-like configuration could increase via 'simple' Na + -exchange processes, promoting fast Li motions

Structural Stability and Electronic Properties of Na2C6O6 for a Rechargeable Sodium-ion Battery

Science.gov (United States)

Yamashita, Tomoki; Fujii, Akihiro; Momida, Hiroyoshi; Oguchi, Tamio

2014-03-01

Sodium-ion batteries have been explored as a promising alternative to lithium-ion batteries owing to a significant advantage of a natural abundance of sodium. Recently, it has been reported that disodium rhodizonate, Na2C6O6, exhibit good electrochemical properties and cycle performance as a minor-metal free organic cathode for sodium-ion batteries. However, its crystal structures during discharge/charge cycle still remain unclear. In this work, we theoretically propose feasible crystal structures of Na2+xC6O6 using first principles calculations. A structural phase transition has been found: Na4C6O6 has a different C6O6 packing arrangement from Na2C6O6. Electronic structures of Na2+xC6O6 during discharge/charge cycle are also discussed. Our predictions could be the key to understanding the discharge/charge process of Na2C6O6. Supported by MEXT program ``Elements Strategy Initiative to Form Core Rersearch Center'' (since 2012), MEXT; Ministry of Education Culture, Sports, Science and Technology, Japan.

Na-ion capacitor using sodium pre-doped hard carbon and activated carbon

International Nuclear Information System (INIS)

Kuratani, Kentaro; Yao, Masaru; Senoh, Hiroshi; Takeichi, Nobuhiko; Sakai, Tetsuo; Kiyobayashi, Tetsu

2012-01-01

We assembled a sodium-ion capacitor (Na-IC) by combining sodium pre-doped hard carbon (HC) as the negative- and activated carbon (AC) as the positive-electrode. The electrochemical properties were compared with two lithium-ion capacitors (Li-ICs) in which the negative electrodes were prepared with Li pre-doped HC and mesocarbon microbeads (MCMB). The positive and negative electrodes were prepared using the established doctor blade method. The negative electrodes were galvanostatically pre-doped with Na or Li to 80% of the full capacity of carbons. The potential of the negative electrodes after pre-doping was around 0.0 V vs. Na/Na + or Li/Li + , which resulted in the higher output potential difference of the Na-IC and Li-ICs than that of the conventional electrochemical double-layer capacitors (EDLCs) because AC positive electrode works in the same principle both in the ion capacitors and in the EDLC. The state-of-charge of the negative electrode varied 80 ± 10% during the electrochemical charging and discharging. The capacity of the cell was evaluated using galvanostatic charge–discharge measurement. At the discharge current density of 10 mA cm −2 , the Na-IC maintained 70% of the capacity that obtained at the current density of 0.5 mA cm −2 , which was comparable to the Li-ICs. At 50 mA cm −2 , the capacities of the Li-IC(MCMB) and the Na-IC dropped to 20% whereas the Li-IC(HC) retained 30% of the capacity observed at 0.5 mA cm −2 . The capacities of the Na-IC and Li-ICs decreased by 9% and 3%, respectively, after 1000 cycles of charging and discharging.

Breakup Reactions and Exclusive Measurements in the 6,7Li+144Sm Systems

International Nuclear Information System (INIS)

Heimann, D. Martinez; Pacheco, A. J.; Arazi, A.; Figueira, J. M.; Negri, A. E.; Capurro, O. A.; Carnelli, P.; Fimiani, L.; Grinberg, P.; Marti, G. V.; Testoni, J. E.; Monteiro, D. S.; Niello, J. O. Fernandez; Marta, H. D.

2009-01-01

The breakup of the projectile-like nuclei in reactions induced by 30 MeV 6 Li and 7 Li beams on a 144 Sm target have been measured through the coincident detection of the in-plane emitted light particles. The primary ion that undergoes breakup has been identified and the physically meaningful variables that characterize the reaction have been obtained on a purely experimental basis. Distributions have been obtained for both the binary emission angle and for the breakup emission angle in the reference frame of the breakup products.

Transition probabilities for the alkali isoelectronic sequences Li I, Na I, K I, Rb I, Cs I, FR I

International Nuclear Information System (INIS)

Lindgard, A.; Nielsen, S.E.

1977-01-01

Dipole transition probabilities, oscillator strengths, lifetimes (mean lives), and branching ratios derived from a numerical Coulomb approximation are presented for experimentally identified (and some extrapolated) states n< or =12, l< or =4 for each of the following members of the alkali sequences (Z/sub net/ is the net charge of the corresponding ion): Li I Z/sub net/=1-15, 17-24 Rb I Z/sub net/=1-6 Na I Z/sub net/=1-24 Cs I Z/sub net/=1-5 K I Z/sub net/=1-7 Fr I Z/sub net/=2,4. The results are presented in transition diagrams and in tables giving energy-level values and transition wavelengths as well. An appendix on hydrogen results for 5< or =n< or =12, 4< or =l< or =11 is included to represent the high-angular-momentum states of all members of the alkali isoelectronic sequences

(6Li,d) reaction on sd-, fp- and g-shell nuclei in ZR- and FR-DWBA formalisms

International Nuclear Information System (INIS)

Rahman, M.A.; Mecking, M.; Strohbusch, U.

1991-06-01

( 6 Li,d) reaction angular distributions on target nuclei 16 ≤ A ≤ 90 have been analyzed using both ZR- and FR-DWBA formalisms. The most prevalent method of analysis of alpha-transfer reactions such as( 6 Li,d) and its reverse (d, 6 Li) (where the wave function at zero distance in the p-state of relative cluster motion in the A = 6 nuclei will not have node) is the ZR-DWBA calculations due to the relatively short time of computation. It is of particular interest to verify whether FR-DWBA calculations result in similar S α - values to those of ZR-DWBA or not. It is found that to derive similar S α -values as in FR-DWBA calculations, one requires relatively large real well depth in ZR-DWBA calculations. Qualitative discussions have been made in this direction. (author). 12 refs, 3 figs, 2 tabs

A novel dual-salts of LiTFSI and LiODFB in LiFePO4-based batteries for suppressing aluminum corrosion and improving cycling stability

Science.gov (United States)

Li, Faqiang; Gong, Yan; Jia, Guofeng; Wang, Qinglei; Peng, Zhengjun; Fan, Wei; Bai, Bing

2015-11-01

The strong corrosion behavior at the Al current collector restricts the application range of lithium bis (trifluoromethanesulfonylimide) (LiTFSI), despite its high stability against water and thermal. SEM, LSV and Tafel curves proved that adding LiODFB into LiTFSI-based electrolytes could suppress aluminum corrosion caused by LiTFSI-based electrolytes. The cycling stability and rate capability of LiFePO4-based batteries using LiTFSI0.6-LiODFB0.4-based electrolytes is excellent as compared to LiFePO4-based batteries using LiPF6-based electrolytes.

Crystal structures of LiCsTiF6 and Cs2TiF6 and interval mobility of complex anions

International Nuclear Information System (INIS)

Popov, D.Yu.; Kavun, V.Ya.; Gerasimenko, A.V.; Sergienko, V.I.; Antokhina, T.F.

2002-01-01

The structure of LiCsTiF 6 (1) and Cs 2 TiF 6 (2) monocrystals was studied by the method of X-ray diffraction analysis. Crystal lattice parameters for compound 1 are: a = 9.251 (1), b = 11.920 (1), c = 10.271 (1), sp.gr. Pbcn, Z = 8; for compound 2: a = 6.213 (1), c = 5.004 (1), sp.gr. P3-bar m1, Z = 1. Three-dimensional frame of bound titanium octahedrons and slightly distorted lithium tetragonal pyramids with Li-F distance ranging from 1.86 to 2.24 A is the crystal structure base of compound 1. The structure of compound 2 is made of dose-packed CsF 3 layers and TiF 6 2- octahedrons located between the layers. The types of internal motion of the complex anions were determined by 10 F NMR method, their activation energy in crystals 1 and 2 in the temperature range of 200-500 K being estimated [ru

Thermal neutron imaging with rare-earth-ion-doped LiCaAlF6 scintillators and a sealed 252Cf source

International Nuclear Information System (INIS)

Kawaguchi, Noriaki; Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui; Kamada, Kei; Fukuda, Kentaro; Suyama, Toshihisa; Watanabe, Kenichi; Yamazaki, Atsushi; Chani, Valery; Yoshikawa, Akira

2011-01-01

Thermal neutron imaging with Ce-doped LiCaAlF 6 crystals has been performed. The prototype of the neutron imager using a Ce-doped LiCaAlF 6 scintillating crystal and a position sensitive photomultiplier tube (PSPMT) which had 64 multi-channel anode was developed. The Ce-doped LiCaAlF 6 single crystal was grown by the Czochralski method. A plate with dimensions of a diameter of 50x2 mm 2 was cut from the grown crystal, polished, and optically coupled to PSPMT by silicone grease. The 252 Cf source ( 6 .

High-pressure X-ray study of LiCrSi₂O₆ clinopyroxene and the general compressibility trends of Li-clinopyroxenes

DEFF Research Database (Denmark)

Periotto, Benedetta; Angel, Ross J.; Nestola, Fabrizio

2013-01-01

High-pressure single-crystal X-ray diffraction measurements of synthetic LiCrSi2O6 clinopyroxene (with space group P21/c) were performed in a diamond-anvil cell up to 7.970 GPa. No phase transition has been observed within the pressure range investigated, but the elastic behavior at lower pressures...... phase transition above 8 GPa to the HP-C2/c space group. A comparison of the Li-clinopyroxenes (M1 = Cr, Al, Sc, Ga, Mg + Fe) previously investigated and our sample shows that their elastic behavior and structural mechanisms of compression are analogous....... derivative K0 = 8.8(6). The structural data measured up to 7.970 GPa confirm that the space group P21/c is maintained throughout the whole pressure range investigated. The atomic parameters, obtained from the integrated diffraction intensities, suggest that the Li coordination polyhedron changes its...

Li3-xNaxV2(PO4)3 (0≤x≤3): Possible anode materials for rechargeable lithium-ion batteries

International Nuclear Information System (INIS)

Wang, Pengfei; Shao, Lianyi; Qian, Shangshu; Yi, Ting-Feng; Yu, Haoxiang; Yan, Lei; Li, Peng; Lin, Xiaoting; Shui, Miao; Shu, Jie

2016-01-01

Highlights: • Li 3-x Na x V 2 (PO 4 ) 3 (0 ≤ x ≤ 3) series are firstly evaluated as anode materials. • Li 3-x Na x V 2 (PO 4 ) 3 anodes show lithium storage activity in 1.0–3.0 V. • The lithium storage capability of different Li 3-x Na x V 2 (PO 4 ) 3 is compared. • Structural reversibility of Li 3-x Na x V 2 (PO 4 ) 3 is studied by in-situ XRD. - Abstract: In this paper, a series of Li 3-x Na x V 2 (PO 4 ) 3 (0 ≤ x ≤ 3) are prepared by a solid state reaction and systematically evaluated as anode materials for lithium-ion batteries. Structural analysis shows that the phase structure of Li 3-x Na x V 2 (PO 4 ) 3 changes along with the evolution of Na content. Charge-discharge tests exhibit that Li 3 V 2 (PO 4 ) 3 shows the highest initial charge specific capacity as high as 88.3 mAh g −1 among all the seven samples, and the reversible capacity is kept at 68.3 mAh g −1 after 45 cycles, corresponding to 77.3% of the initial charge capacity. With increasing of Na content in Li 3-x Na x V 2 (PO 4 ) 3 , the as-obtained sample show poorer lithium storage capability than Li 3 V 2 (PO 4 ) 3 . As a result, Na 3 V 2 (PO 4 ) 3 shows the inferior cycling performance than other Li 3-x Na x V 2 (PO 4 ) 3 . It can only deliver a reversible capacity of 20.9 mAh g −1 after 45 cycles, corresponding to 45.9% of the initial charge capacity. In-situ X-ray diffraction observations demonstrate that the poor electrochemical property of Na 3 V 2 (PO 4 ) 3 anode is due to the irreversible structural evolution during charge-discharge process. Therefore, reducing the Na 3 V 2 (PO 4 ) 3 phase in as-obtained sample is a feasible route to improve the lithium storage capability of Li 3-x Na x V 2 (PO 4 ) 3 .

Sum rule for bremsstrahlung cross section for 6Li in the resonating-group method

International Nuclear Information System (INIS)

Lodhi, M.A.K.; Wood, K.E.

1982-01-01

In the method of resonating-group structure, the wave function of 6 Li is assumed to have a single channel of alpha and deuteron substructures in the ground state. It is shown that the intercluster exchange of nucleons is an important effect which causes significant change in the root mean square radius and the dipole transition cross section. Due to lack of symmetry in space coordinates of 6 Li, the dipole operator is not identical to the mean square operator for this sum rule calculation and is expected to display like behavior in similar systems. It is also shown that the deuteron substructure in this nucleus is substantially larger than the alpha substructure. (orig.)