Graphene fluoride as a conductive agent for Li-argyrodite electrolyte containing all-solid-state batteries

Abstract

A sulfide-based Li-argyrodite, Li6PS5X (X = Cl, Br, I), is a promising solid-state electrolyte candidate for next-generation all-solid-state batteries. The compound features high ionic conductivity, which is attributed to the high polarizability of sulfur and anion site disorder, providing advantageous crystallographic geometries for Li-ions to occupy and diffuse. However, the chemical instability of Li6PS5Cl during cycling limits its implementation in practical applications. This study employs graphene fluoride as a conductive agent for the cathode composite to alleviate the undesirable decomposition reactions at the electrolyte interface. The combined measurements of time-dependent X-ray photoelectron spectroscopy and electrochemical analysis confirmed that graphene fluoride significantly enhances the chemical stability of the electrolyte interface, yielding a stable cycling performance.