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

We investigated the effect of epicyanohydrin as an additive to a LiPF 6 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 LiNi 0.6 Co 0.2 Mn 0.2 O 2 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).