Nano‐Crosslinked Polyether‐Based Gel Polymer Electrolytes for Interface‐Stable High‐Voltage Lithium‐Ion Batteries

ABSTRACT Gel polymer electrolytes hold practical promise for high‐energy‐density and safe lithium‐ion batteries. However, the use of solvents always compromises mechanical strength and triggers undesirable interfacial side reactions. Herein, a two‐step strategy involving triethoxysilylation of polyethylene glycol (PEG) and subsequent silane coupling with laponite (LAP) is proposed to fabricate the nano‐crosslinked gel polymer electrolyte tailored for interface‐stable lithium‐ion batteries. The LAP nanosheets bridge isolated polymer chains into a 3D network, enhancing mechanical integrity and establishing continuous Li + pathways. Notably, a critical solvation‐regulation mechanism is explicitly clarified, where the anchoring effect of LAP on solvent molecules weakens Li + ‐solvent coordination and allows more anions to enter the solvation sheath, fostering robust, LiF‐rich interphases. Benefiting from this, the interfacial side reactions on the lithium anode and high‐voltage cathode are both greatly suppressed. As a result, the nano‐crosslinked electrolyte demonstrates an ultra‐long symmetric cell cycling life exceeding 6600 h (0.1 mA cm −2 ), stable LiFePO 4 /Li cell operation for over 1300 cycles (0.5 C) and high‐voltage LiNi 0.9 Co 0.05 Mn 0.05 O 2 /Li cell cycling for more than 450 cycles (5 C). This work establishes a nano‐crosslinking design paradigm toward advanced gel polymer electrolytes, offering insights into solvation structure regulation as the key to stabilizing electrode/electrolyte interfaces in practical lithium‐ion batteries.