Microemulsion Engineering Reconciles Propylene Carbonate Electrolytes and Graphite Anodes for All‐Climate Lithium‐Ion Batteries

Abstract

Abstract Propylene carbonate (PC)‐based electrolytes are promising for all‐climate lithium‐ion batteries due to their wide liquid range. However, detrimental Li + ‐PC co‐intercalation causes severe graphite (Gr) anode exfoliation, remaining the biggest barrier for their practical application. Although the issue can be mitigated via solvation regulation, complex interfacial chemistry limits long‐term cycling ability. Herein, we designed a PC‐based microemulsion electrolyte to achieve PC/Gr compatibility through interfacial manipulation. Specifically, insoluble glyceryl monostearate (GMS) and amphiphilic tetrahydrofuran (THF) are introduced into the PC‐based electrolyte. GMS self‐assembles in THF to form core‐shell GMS@THF micelles dispersed in the continuous PC electrolyte medium. This microemulsion structure generates abundant liquid‐liquid interfacial tension at micelle/electrolyte interfaces, spontaneously directing micelles to the electrode interfaces during operation. At the Gr anode, adsorbed GMS@THF micelles leverage solvophobic effects to synergistically form PC‐poor Li + solvation sheaths and block free PC, effectively suppressing detrimental PC co‐intercalation. This design enables Li||Gr cells achieve a high initial Coulombic efficiency of 92.8% and supports 1 Ah Gr||LiFePO 4 pouch cells to operate over 4000 cycles. Remarkably, the pouch cells work well across extreme temperatures (−40∼100 °C cycling; −60∼100 °C operation), demonstrating exceptional all‐climate capability. This microemulsion engineering establishes a universal paradigm for optimizing electrolyte/electrode interphases in the PC/Gr system.