Control of LiFePO4 air-aging through the use of electrolyte additive

•Diethylamino trimethylsilane scavenges acidic impurities, surface structural OH or HF.•Dissolution of LiFePO4 in LiPF6 electrolyte is successfully contained.•Outstanding electrochemical performance is obtained from severely air-aged materials.•MAS NMR shows that the interphasial chemistry is governed by the additive.

Air-aged LiFePO4 exhibits an OH-rich surface that reacts with LiPF6 based electrolyte, leading to poor battery performance. We show that outstanding electrochemical performance is achieved when using air-aged LiFePO4 in the presence of electrolyte additive N,N-diethylamino trimethylsilane, capable of reacting with acidic impurities. Stable impedance is obtained upon cycling, and 7Li and 19F MAS NMR study indicates that the interphasial chemistry is governed by a surface layer coming from reacted additive.