Abstract: High-voltage Li ion batteries (LIBs) are often compromised by lower cycle life due to enhanced degradation of cathode material, e.g., LiNi0.6Co0.2Mn0.2O2 (NCM622). Crucial is the initiated electrode crosstalk, i.e., transition metal (TM) dissolution from the cathode and subsequent deposition on the anode, as it forces formation of high surface area lithium, capacity losses and risk of Li dendrite penetration, finally leading to an abrupt end-of-life (literature-known as sudden death failure).

A pragmatic approach to prolong cycle life is the electrolyte manipulation towards formation/presence of fluorophosphates, as they effectively suppress electrode crosstalk via TM scavenging. LiDFP-content sensitively depends on factors, such as storage temperature of electrolyte or the type of separator.

Fluorophosphates easily decompose to toxic organofluorophosphates (OFPs). It is demonstrated that a dual-additive approach with fluoroethylene carbonate (FEC) suppresses the OFP content without sacrificing LIB performance.