Quantum Mechanics Reactive Dynamics Study of Solid Li-Electrode/Li_6PS_5Cl-Electrolyte Interface

Abstract

We have performed a theoretical study of the Li/Li_6PS_5Cl interface and showed the ability of the applied computational methods to properly describe the chemical processes that occurs at the interface. After a 500 ps ab initio molecular dynamics simulation, we find that the Li/Li_6PS_5Cl interface decomposes with formation of multiple phases and the main decomposition products are Li_2S, Li_3P, LiCl, and possibly LiP. These findings are in good agreement with reported experimental data. The observed quick decomposition is attributed to the weak bonding between P and S. Basing on this and earlier obtained experimental results, we conclude that the chemical instability may be an intrinsic problem of PS based solid electrolytes when they are in contact with Li-metal. Our results validate effectivity of the available computational tools to reach a deeper insight into the evolution of interfacial structures and properties prior to experiment.

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