Showing papers by "Kota Suzuki published in 2017"
TL;DR: In this article, solid solutions of Sn-Si derivatives with an LGPS (Li10GeP2S12)-type structure are synthesized by a solid-state reaction in the Li3PS4−Li4SnS4-Li4SiS4 quasi-ternary system.
Abstract: Solid solutions of Sn–Si derivatives with an LGPS (Li10GeP2S12)-type structure are synthesized by a solid-state reaction in the Li3PS4–Li4SnS4–Li4SiS4 quasi-ternary system. The monophasic region of the LGPS-type structure deviates from the tie line between Li10SiP2S12 and Li10SnP2S12, and the composition of the solid solution is determined to be −0.1 ≤ δ ≤ 0.5 and 0 ≤ y ≤ 1.0 in Li10+δ[SnySi1–y]1+δP2−δS12 (0.50 ≤ x ≤ 0.7 and 0 ≤ y ≤ 1.0 in Li4–x[SnySi1–y]1–xPxS4). The solid solution is formed by a double substitution that changes the Sn/Si ratio and the M4+ (Sn4+ and Si4+)/P5+ ratio, which adjusts the sizes of the lithium conduction tunnels and the lithium concentration, and contributes to the optimal conductivity value. The highest ionic conductivity value of 1.1 × 10–2 S cm–1 is achieved for the composition of Li10.35[Sn0.27Si1.08]P1.65S12 (Li3.45[Sn0.09Si0.36]P0.55S4) at 298 K, which is close to the value for the original LGPS compound (1.2 × 10–2 S cm–1). The Ge-free solid electrolyte could be suitabl...
109 citations
TL;DR: In this article, a high-temperature mechanical milling (443 K) was used for the fabrication of a composite electrode with high reversible electrochemical activities for use in an all-solid-state lithium-sulfur battery.
43 citations
TL;DR: Li7Ge3PS12 as discussed by the authors was synthesized by slow cooling from the ternary Li2S-GeS2-P2S5 system, and was shown to exhibit a cubic argyrodite-type structure.
37 citations
TL;DR: In this article, the H conductive oxyhydride, LaSrLiH2O2 (x = 0, y = 1 in LSLHO), was synthesized by a conventional solidstate reaction at ambient pressure.
Abstract: Recently, hydride ion (H) has come to be recognized as new charge carrier for the transport of hydrogen in solids by realization of pure H− conduction in BaH2 and La2−x−ySrx+yLiH1−x+yO3−y oxyhydride system (LSLHO). In this study, the H conductive oxyhydride, LaSrLiH2O2 (x = 0, y = 1 in LSLHO), was synthesized by a conventional solidstate reaction at ambient pressure. The crystal structure of LaSrLiH2O2, as well as the H conductivity and bonding state of hydrogen, was examined by Rietveld analysis using X-ray and neutron diffraction data, attenuated total reflection Fourier transform spectroscopy (ATR-FTIR), and electrochemical impedance spectroscopy (EIS). The sample synthesized at ambient pressure had a K2NiF4-type layered perovskite structure composed of alternately stacked tetragonal (LiH2) and (LaSrO2) layers, and exhibited a conductivity of H of 3.2 × 10−6Scm−1 at 300°C, which were the same structure and property as that reported previously for a sample synthesized by high-pressure synthesis. © The Electrochemical Society of Japan, All rights reserved.
19 citations
17 citations
TL;DR: Amorphous Li3PS4 films were synthesized by pulsed laser deposition (PLD) at room temperature using Li 3PS4 targets with excess lithium and sulfur in this article.
Abstract: Amorphous Li3PS4 films were synthesized by pulsed laser deposition (PLD) at room temperature using Li3PS4 targets with excess lithium and sulfur. Raman and X-ray photoemission spectroscopies indicated that the Li3PS4 film synthesized with a stoichiometric amount of Li3PS4 target contained lithium-deficient phases such as Li4P2S6, Li2−xS and sulfur due to composition deviation caused during the ablation process. The film synthesized with a 14% Li2S-excess target (Li3.42PS4.21) contained fewer impurities, and exhibited a higher ionic conductivity of 5.3 × 10−4 S/cm at 298 K than the lithium-deficient film (3.1 × 10−4 S/cm). The target composition is an important factor for the fabrication of highly conductive Li3PS4 films for electrolytes in thin-film batteries.
16 citations
TL;DR: Local crystalline structures of LiCoO2 nanothin film cathodes in a lithium ion battery have been spectroscopically elucidated through confocal Raman imaging analysis and a significant difference in the crystalline structure is found between the nanometric thin films and bulk powders.
Abstract: Local crystalline structures of LiCoO2 nanothin film cathodes in a lithium ion battery have been spectroscopically elucidated through confocal Raman imaging analysis at high spatial resolution of several hundred nanometers. A significant difference in the crystalline structure is found between the nanometric thin films and bulk powders. Thermally induced local decomposition of LiCoO2 into an impurity phase on the films has also been revealed along with the mechanism of the temperature-triggered decomposition process. Moreover, frequency-based Raman imaging enables us to locally probe spatial separation between stoichiometric (LiCoO2) and non-stoichiometric (Li1-xCoO2, 0 < x < 1) crystal phases on the thin films. Such local crystalline analysis is a promising approach to provide new insights into the degradation mechanism of lithium-ion batteries, which would result in improving the performance of thin film-based lithium ion batteries.
12 citations
TL;DR: In this paper, the deterioration mechanism of Li(Ni, Co, Mn)O 2 and Zr-O surface modified electrodes was elucidated using epitaxial thin films synthesized by pulsed laser deposition.
10 citations
3 citations
TL;DR: In this article, the feasibility of micrometer scale analysis of lithium distribution in the all-solid-state lithium battery using a sulfide-based solid electrolyte was confirmed.
Abstract: For confirming the feasibility of micrometer scale analysis of lithium distribution in the all-solid-state lithium battery using a sulfide-based solid electrolyte, the cross-section of pellet type ...
3 citations
TL;DR: In this article, a plasmonic metallic tip was employed to enhance and probe the electric field in close proximity to the LiCoO2 thin film, since it is correlated with the lithium-ion concentration at the surface.
Abstract: Nanoscale analysis of the local lithium-ion concentration in lithium-ion battery cathode materials is essential for achieving high-performance batteries. We developed a near-field optical technique to visualize the lithium-ion distribution in a lithium-ion battery cathode on a nanometer scale. A plasmonic metallic tip was employed to locally enhance and probe the electric field in close proximity to the LiCoO2 thin film, since it is correlated with the lithium-ion concentration at the surface. We also utilized this technique to map the electrochemically induced ion diffusion at the grain boundaries under the application of a DC voltage to the surface through the plasmonic metallic tip.