Ab initio Study on Lithium Anode Interface Instability and Stabilization of Superionic Li3InCl6 and Li6PS5Cl Solid Electrolytes

TL;DR

This study uses ab initio calculations to analyze the stability of lithium metal interfaces with superionic conductors Li3InCl6 and Li6PS5Cl, identifying stable interphases and interlayers to improve solid-state lithium batteries.

Contribution

It provides new insights into the thermodynamic stability of LIC-Li and LPSC-Li interfaces and identifies suitable interlayers for enhanced interface stability in ASSLBs.

Findings

LPSC-Li interface forms a stable interphase.

LIC-Li interface is thermodynamically unstable.

Identified interlayers improve interface stability.

Abstract

Emerging superionic conductors Li3InCl6 (LIC) and Li6PS5Cl (LPSC) are very promising for solid-state electrolytes (SSEs) in all-solid-state lithium batteries (ASSLBs). However, unstable lithium-anode interfaces in LIC and LPSC have been observed through experiments and ab initio calculations, while the interphases formed in determining interfacial stability remain unclear. In this study, we investigate the ab initio stability of LIC-Li and LPSC-Li interfaces and interphases. Our ab initio calculations revealed that both interfaces are not chemically or electrochemically thermodynamically stable. Interestingly, the LPSC-Li has a stable interphase, but the LIC-Li doesn't. Moreover, the interlayers were systematically evaluated for the LIC-Li and LPSC-Li interfaces, and the desired interlayer materials are clarified for the two interfaces. This ab initio understanding of the interfaces, interphases and interlayers would help the development of a variety of stable interfaces in ASSLBs.