Interfacial processes at single-crystal β-Sn electrodes in organic carbonate electrolytes

Abstract

In situ atomic force microscopy (AFM) and spectroscopic ellipsometry were used to study the mechanism of organic carbonate electrolytes decomposition and surface layer (re)formation at β-Sn(001) and (100) single crystal electrodes. Interfacial phenomena were investigated at potentials above 0.8 V vs. Li/Li +, i.e. where no Sn–Li alloying takes place. The Sn(001) electrode tends to form a protective surface layer of electrolyte reduction products during the first cathodic CV scan, which effectively inhibits further reduction of the electrolyte upon cycling. In contrast, the Sn(100) electrode produces a thick, inhomogeneous and unstable surface layer. The observed significant difference of Sn reactivity toward the electrolyte as a function of Sn surface crystalline orientation suggests radically different reaction paths, reduction products, and properties of the surface film.