Space鈥揅harge Layer Effect at Interface between Oxide Cathode and Sulfide Electrolyte in All-Solid-State Lithium-Ion Battery

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• 作者：Jun Haruyama ; Keitaro Sodeyama ; Liyuan Han ; Kazunori Takada ; Yoshitaka Tateyama
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：July 22, 2014
• 年：2014
• 卷：26
• 期：14
• 页码：4248-4255
• 全文大小：475K
• ISSN：1520-5002

文摘

We theoretically elucidated the characteristics of the space鈥揷harge layer (SCL) at interfaces between oxide cathode and sulfide electrolyte in all-solid-state lithium-ion batteries (ASS-LIBs) and the effect of the buffer layer interposition, for the first time, via the calculations with density functional theory (DFT) + U framework. As a most representative system, we examined the interfaces between LiCoO₂ cathode and 尾-Li₃PS₄ solid electrolyte (LCO/LPS), and the LiCoO₂/LiNbO₃/尾-Li₃PS₄ (LCO/LNO/LPS) interfaces with the LiNbO₃ buffer layers. The DFT+U calculations, coupling with a systematic procedure for interface matching, showed the stable structures and the electronic states of the interfaces. The LCO/LPS interface has attractive Li adsorption sites and rather disordered structure, whereas the interposition of the LNO buffer layers forms smooth interfaces without Li adsorption sites for both LCO and LPS sides. The calculated energies of the Li-vacancy formation and the Li migration reveal that subsurface Li in the LPS side can begin to transfer at the under-voltage condition in the LCO/LPS interface, which suggests the SCL growth at the beginning of charging, leading to the interfacial resistance. The LNO interposition suppresses this growth of SCL and provides smooth Li transport paths free from the possible bottlenecks. These aspects on the atomic scale will give a useful perspective for the further improvement of the ASS-LIB performance.