Epicyanohydrin as an Interface Stabilizer Agent for Cathodes of Li-Ion Batteries

Abstract

We investigated the effect of epicyanohydrin as an additive to a LiPF6 salt–based electrolyte in 1:1:1 EC:EMC:DMC for high-power lithium-ion batteries operated at 60°C. Epicyanohydrin polymerized to form a thermally stable, thin, conductive, and evenly distributed protective film on the cathode surface, preventing dissolution of the cathode material LiNi0.6Co0.2Mn0.2O2 and suppressing interfacial impedance, thereby protecting the surface from further reaction with the electrolyte at 60°C. The cycling performance of the cathode materials with the additive was enhanced due to the formation of an epicyanohydrin-derived polymer solid electrolyte interface (SEI).