Lithium-Ion Intercalation into Graphite in SO-Based Inorganic Electrolyte toward High-Rate-Capable and Safe Lithium-Ion Batteries.

Herein, we have identified that lithium ions in an SO-based inorganic electrolyte reversibly intercalate and deintercalate into/out of graphite electrode using ex situ X-ray diffraction and various electrochemical methods. X-ray photoelectron spectroscopy shows that the solid electrolyte interphase on the graphite electrode is mainly composed of inorganic compounds, such as LiCl and lithium sulfur-oxy compounds. Graphite electrode in SO-based inorganic electrolyte has stable capacity retention up to 100 cycles and outstanding rate capability performance. This can be attributed to low interfacial impedance and high ionic conductivity of SO-based inorganic electrolyte, which are superior to those of conventional organic electrolytes. Considering the remarkable rate capability and intrinsically nonflammable properties of the electrolyte, use of graphite and an SO electrolyte will likely facilitate the development of advanced lithium-ion batteries.