Deciphering Interfacial Stability of Sulfide and Halide-Based Electrolytes via Operando X-ray Photoelectron Spectroscopy.

Liu, Zhicong; Tao, Jianming; Jiang, Han; Wu, Yubing; Lin, Liang; Yang, Yanmin; Chen, Yue; Huang, Zhigao et al. · Nano Lett · 2025

basic_science · Level V

Where this comes from

Abstract

Combined solid electrolytes address cathode-anode compatibility in all-solid-state Li-ion batteries (ASSLBs), yet interface stability and ion transport mechanisms between different electrolytes remain unclear. Herein, we investigate Li<sub>6</sub>PS<sub>5</sub>Cl (LPSC), Li<sub>3</sub>InCl<sub>6</sub> (LIC), and Li<sub>1.75</sub>ZrO<sub>0.5</sub>Cl<sub>4.75</sub> (LZOC) composite electrolytes through electrochemical analysis and operando X-ray photoelectron spectroscopy. Our results reveal that the electrostatic potential difference between LPSC and LIC inhibits Li<sup>+</sup> migration, leading to the decomposition of LIC into InCl<sub>3</sub> and LiCl, causing battery failure. In contrast, LZOC forms an oxygen-rich interphase with LiCoO<sub>2</sub> (LCO), showing better interfacial stability. The electrostatic potential difference between LZOC and LPSC promotes Li<sup>+</sup> diffusion, maintaining interface stability even as LPSC decomposes, thereby preventing severe degradation of LZOC. Therefore, the LCO-LZOC composite cathode exhibits better electrochemical performance than LCO-LIC. This study elucidates the basic mechanism of interfacial reaction and ion diffusion in sulfide-halide electrolytes and emphasizes the key role of electrolyte compatibility in ASSLBs failure pathways.