1,3,5-Trifluorobenzene endorsed EC-free electrolyte for high-voltage and wide-temperature lithium-ion batteries

Abstract

Ethylene carbonate (EC) is susceptible to the aggressive chemistry of nickel-rich cathodes, making it undesirable for high-voltage lithium-ion batteries (LIBs). The arbitrary elimination of EC leads to better oxidative tolerance but always incurs interfacial degradation and electrolyte decomposition. Herein, an EC-free electrolyte is deliberately developed based on gradient solvation by pairing solvation-protection agent (1,3,5-trifluorobenzene, F3B) with propylene carbonate (PC)/methyl ethyl carbonate (EMC) formulation. F3B keeps out of inner coordination shell but decomposes preferentially to construct robust interphase, inhibiting solvent decomposition and electrode corrosion. Thereby, the optimized electrolyte (1.1 M) with wide liquid range (−70–77 °C) conveys decent interfacial compatibility and high-voltage stability (4.6 V for LiNi0.6Mn0.2Co0.2O2, NCM622), qualifying reliable operation of practical NCM/graphite pouch cell (81.1% capacity retention over 600 cycles at 0.5 C). The solvation preservation and interface protection from F3B blaze a new avenue for developing high-voltage electrolytes in next-generation LIBs.