In this work, an industrially produced polymer electrolyte based on the poly(ethylene oxide) PEO-LiTFSI is studied. The evolution of the impedance spectra of symmetric cells Li/PEO-LiTFSI/Li with the aging time at 90degC is presented. The variation of impedance spectra as a function of temperature and electrolyte geometry is also shown, especially the low frequency part (up to 0.5 mHz). An equivalent electrical circuit is proposed to describe the whole spectra. The major contributions to the impedance of this interface are identified. From the low frequency contribution, the salt diffusion coefficient is determined. Finally, we use a simple model of the surface layer to gain some insight into its properties
Sergey V. Mirnov
Andrey G. Alekseev
Alexandr M. Belov
Nadejda T. Djigailo
Anastasiya N. Kostina
Vladimir B. Lazarev
Igor E. Lyublinski
Vladislav M. Nesterenko
Aleksei V. Vertkov
Vladimir A. Vershkov
The concept of a steady state tokamak with plasma facing components (PFC) on the basis of liquid lithium circulation demands the decision of three tasks: lithium injection to the plasma, lithium ions collection before their deposition on the vacuum vessel and lithium returning to the injection zone. Main subject of paper is the investigations of Li collection by different types of limiters intersected the scrape-of-layer (SOL) in T-10 and T-11M tokamaks. For finding solution for this problem in T-11M and T-10, experiments have been applied with Li-, C-rail limiters and ring SS R-limiter-collector (T-11M). The efficiency of Li collection by limiters in T-11M and T-10 tokamaks was investigated by post mortem sample-witness analysis and (T-11M) by the use of the mobile graphite probe (limiter) as a recombination target in the stream of lithium ions. The characteristic depth of lithium penetration in the SOL area of T-11M is about 2cm and 4cm in SOL of T-10. The quantitative analysis of the sample-witnesses located on T-11M limiters showed that 60+or-20% of the lithium injected during plasma operating of T-11M had been collected by limiters. It confirms an opportunity of the lithium ions collection by limiters in tokamak SOL. [All rights reserved Elsevier].
Tetragonal Li10GeP2S12 (LGPS) is the best solid Li electrolyte reported in the literature. In this study we present the first in-depth study on the structure and Li ion dynamics of this structure type. We prepared two different tetragonal LGPS samples, Li10GeP2S12 and the new compound Li7GePS8. The Li ion dynamics and the structure of these materials were characterized using a multitude of complementary techniques, including impedance spectroscopy, Li-7 PFG NMR, Li-7 NMR relaxometry, X-ray diffraction, electron diffraction, and P-31 MAS NMR. The exceptionally high ionic conductivity of tetragonal LGPS of similar to 10(-2) S cm(-1) is traced back to nearly isotropic Li hopping processes in the bulk lattice of LGPS with E-A approximate to 0.22 eV.
Highlights • Thermodynamic optimization of the Ag–Li system was carried at first time. • Thermodynamic re-optimizations of the Ag–Ca, Ag–Zn, Ca–In and Ca–Li binary systems were carried. • A self-consistent thermodynamic database was constructed for the Ag–(Ca, Li, and Zn) and Ca–(In, Li) binary systems. Abstract Critical evaluations and thermodynamic modeling of the Ag-(Ca, Li, and Zn) and Ca-(In, Li) binary systems are presented. Thermodynamic optimization of the Ag–Li binary system was carried out in the present work at first. Thermodynamic re-optimizations of the Ag–Ca, Ag–Zn, Ca–In and Ca–Li binary systems were carried out in the present work, which presents improvements in comparison with previous works. The Modified Quasichemical Model in the Pair Approximation (MQMPA) was used for the liquid solution; this model is particularly suited for liquid which exhibits a high degree of short-range order. The intermetallic compounds are modeled with the Compound Energy Formalism (CEF), and terminal solid solutions are modeled with Bragg–Williams model (BWM) with sub-regular solution approximation. All available and reliable experimental data are reproduced within experimental error limits. A self-consistent thermodynamic database was constructed for the Ag–(Ca, Li, and Zn) and Ca–(In, Li) binary systems, which as a part of the thermodynamic database of the Mg–X (X: Ag, Ca, In, Li, Na, Sn, Sr, and Zn) multi-component system shall facilitate the development of Mg alloys for practical industrial purposes.
Mahmudi, R.
Shalbafi, M.
Karami, M.
Geranmayeh, A.R.
Creep behavior of the hcp Mg-4Li-1Zn (LZ41), hcp/bcc Mg-8Li-1Zn (LZ81), and bcc Mg-12Li-1Zn (LZ121) cast alloys was studied by long-term Vickers indentation testing in the temperature range of 423-498 K and under constant load of 5 N. It was established that increasing Li content decreased the creep resistance at all test temperatures. This was stemmed from the effect of Li on the crystal structure of the alloys, the increment of which increased the volume fraction of the bcc beta-phase. This phase activated non-basal slip and facilitated the slip-assisted deformation, and thus, resulted in lower strength and creep resistance. The average stress exponents of about 7.0, 4.5, and 4.2 and activation energies of 90.0, 91.7 and 98.2 kJ/mol were obtained for the LZ41, LZ81, and LZ121 alloys, respectively. It is suggested that the operative creep mechanism is dislocation pipe diffusion in the LZ41 alloy, and pipe-diffusion-controlled dislocation viscous glide in the LZ81 and LZ121 alloys. (C) 2015 Elsevier Ltd. All rights reserved.
A cathode material with excellent capacity and output characteristics and safety, and a lithium ion secondary battery using the same is provided. The invention relates to a cathode material which includes a mixture of a cathode active material having a large primary particle size with excellent capacity characteristics and represented by the composition formula: Lix1Nia1Mnb1Coc1O2, where 0.2≦x1≦1.2, 0.6≦a1, 0.05≦b1≦0.3, 0.05≦c1≦0.3, and another cathode active material having a small primary particle size with excellent output characteristics and represented by the composition formula: Lix2Nia2Mnb2Coc2O2, where 0.2≦x2≦1.2, a2≦0.5, 0.05≦b2≦0.5, 0.05≦c2≦0.5. The invention also relates to a lithium ion secondary battery using the cathode material.
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