Fluorine Sustained-Release Gel Polymer Electrolytes for High-Energy-Density and Wide-Temperature Solid-State Lithium...

Wide-temperature and high-voltage environments impose unprecedented demands on electrolyte stability, where conventional systems tend to fail due to severe by-products generation and cathode-electrolyte interphase (CEI) / solid electrolyte interface (SEI) corrosion. Herein, a molecularly engineered cross-linker (pentafluorobutyl acrylate, PFPA) is proposed to achieve rapid self-repairing of CEI/SEI through sequential fluorine release. It is revealed that the grafted pentafluorophenyl groups of PFPA can suppress harmful hydrolysis preventatively and increase the Li⁺ transference number by implanting PF₆ ^-, and achieve the construction and continuous self-repairing of LiF-rich CEI/SEI. As a result, the cells incorporating modified electrolytes (GPE-F) exhibit excellent electrochemical performance under a high cut-off voltage (∼4.7 V) and a wide temperature range (-20∼70°C). The NCM811||GPE-F||Li pouch cell with 403.6 Wh kg^-1 delivers a high-capacity retention of 91.3% after 380 cycles, and the NCM811||GPE-F||Gr pouch cell with 265.5 Wh kg^-1 can be stably cycled for over 2000 cycles. The industrial viability is further demonstrated in high-capacity (11.1 Ah), high-energy-density pouch cells (544.3 Wh kg^-1). This work provides a novel and promising pathway for the development of multi-system compatible gel polymer electrolytes, particularly for their application in complex and harsh operating environments.