A Weakly-Solvating Propylene Carbonate Electrolyte for High-Voltage and Low-Temperature Lithium-Ion Batteries

Next-generation lithium-ion batteries (LIBs) require electrolytes compatible with high-voltage (>4.3 V) and low-temperature (<-10 °C) operation, yet commercial ethylene carbonate (EC)-based systems remain constrained by intrinsic limitations including poor oxidation stability at cathode side and high melting points. Although propylene carbonate (PC) demonstrates superior oxidative stability and lower melting temperature than EC, its tendency to cointercalate with Li⁺ within the graphite anode interlayers restricts its applicability in LIBs. We propose a PC-based weakly-solvating electrolyte engineered with difluoroethylene carbonate (DFEC) that resolves interfacial challenges at both electrodes. The PC solvent facilitates oxidative resistance through formation of an inorganic-dominated cathode-electrolyte interphase (CEI), effectively mitigating transition metal dissolution at 4.4 V operation. Simultaneously, DFEC disrupts Li⁺-PC coordination through reduced solvent molecule numbers in the solvation shell, enabling generation of a stable solid electrolyte interphase (SEI) on graphite anodes with minimized interfacial impedance. Implemented in 5 Ah pouch cells, this electrolyte demonstrates 76.7% capacity retention after 2000 cycles (2.8-4.4 V) at room temperature (RT) and maintains 91% of its RT capacity at -20 °C, surpassing conventional EC-based electrolytes. This work presents an electrolyte engineering approach that synergistically addresses high-voltage durability and low-temperature functionality, providing a scalable solution for advanced LIB technologies.