An Electrode‐Crosstalk‐Suppressing Smart Polymer Electrolyte for High Safety Lithium‐Ion Batteries
Tiantian Dong, Gaojie Xu, Bin Xie, Tao Liu, Tianyu Gong, Chenghao Sun, Jinzhi Wang, Shu Zhang, Xiaohu Zhang, Huanrui Zhang, Lang Huang, Guanglei Cui
Abstract
Abstract Electrode crosstalk between anode and cathode at elevated temperatures is identified as a real culprit triggering the thermal runaway of lithium‐ion batteries. Herein, to address this challenge, a novel smart polymer electrolyte is prepared through in situ polymerization of methyl methacrylate and acrylic anhydride monomers within a succinonitrile‐based dual‐anion deep eutectic solvent. Owing to the abundant active unsaturated double bonds on the as‐obtained polymer matrix end, this smart polymer electrolyte can spontaneously form a dense crosslinked polymer network under elevated temperatures, effectively slowing down the crosstalk diffusion kinetics of lithium ions and active gases. Impressively, LiCoO 2 /graphite pouch cells employing this smart polymer electrolyte demonstrate no thermal runaway even at the temperature up to 250 °C via accelerating rate calorimeter testing. Meanwhile, because of its abundance of functional motifs, this smart polymer electrolyte can facilitate the formation of stable and thermally robust electrode/electrolyte interface on both electrodes, ensuring the long cycle life and high safety of LIBs. In specific, this smart polymer electrolyte endows 1.1 Ah LiCoO 2 /graphite pouch cell with a capacity retention of 96% after 398 cycles at 0.2 C.