Inhibition of transition-metal dissolution with an inert soluble product interface constructed by high-concentration electrolyte

The formation of a compact and stable cathode electrolyte interphase (CEI) film is a promising way to improve the high voltage resistance of lithium-ion batteries (LIBs). However, challenges arise due to the corrosion of hydrogen fluoride (HF) and the dissolution of transition metal ions (TMs) in harsh conditions. To address this issue, researchers have constructed an anion-derived CEI film enriched with LiF and LiPO 2 F 2 soluble product on the surface of LiNi 0.5 Mn 1.5 O 4 (LNMO) cathode in highly concentrated electrolytes (HCEs). The strong binding of LiF and LiPO 2 F 2 generated an inert LiPO 2 F 2 soluble product interface, which inhibited HF corrosion and maintained the spinel structure of LNMO, contributing to a capacity retention of 92% after 200 cycles at 55°C in the resulting cell with a soluble LiPO 2 F 2 -containing CEI film. This new approach sheds light on improving the electrode/electrolyte interface for high-energy LIBs.