Non-Flammable Fluorinated Phosphorus(III)-Based Electrolytes for Advanced Lithium-Ion Battery Performance

In the quest for ever higher energy and power densities of lithium-based batteries, numerous functional materials are being utilized, however in many cases their highly reactive nature is likely to increase the risk of danger in case of battery failures. This especially affects the aprotic non-aqueous organic carbonate-based electrolyte, still considered as the state-of-the-art (SOTA) and its volatile and highly flammable components. Efforts to identify different forms of flame-retardants or nonflammable electrolyte solvents/co-solvents to reduce the risk of fire or explosion are inevitably followed by a trade-off between the improved safety and deteriorated overall cycling performance of a battery. Here, we report on a smartly tailored, multifunctional nonflammable electrolyte formulation comprising 15.0 wt.% 2-(2,2,3,3,3-pentafluoro-propoxy)-4-(trifluormethyl)-1,3,2-dioxaphospholane (PFPOEPi-1CF(3)), significantly advancing the cycling performance of the NMC111||graphite cells by formation of an effective interphase on/at both anode and cathode and correlate its performance to the 2-(2,2,3,3,3-pentafluoropropoxy)-1,3,2-dioxaphospholane (PFPOEPi) containing electrolyte counterpart by establishing a strong structure-reactivity-performance-relationship.