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

Abstract

ABSTRACT 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 PF 6 − , 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.