Research Progress of Ion-initiated in situ Generated Solid Polymer Electrolytes for High-safety Lithium Batteries^★

Abstract

Lithium-ion batteries, widely used in many aspects of the national economy such as electric vehicles, mobile intelligent devices and large-scale energy storage, have gradually entered special applications area including deep sea, deep space, deep ground and individual combat equipment. However, lithium batteries using traditional carbonate liquid electrolytes often suffer from potential safety risk such as electrolyte leakage, flammability and explosion, so it is urgent to develop a new generation of high-safety solid electrolytes. Among them, solid polymer electrolytes have attracted great attention because of their superior mechanical flexibility and compatibility with the main production processes of lithium battery. In terms of preparation process, solid polymer electrolytes prepared via solution-casting often easily lead to high interfacial resistance and then deteriorate the battery performance. In contrast, liquid organic precursors used in in-situ polymerization strategy can sufficiently penetrate the positive and negative electrodes to guarantee superior interfacial compatibility and efficient ionic conduction. At present, most of in-situ polymerization strategies are based on free radical thermal polymerization with additional initiators and the need for harsh conditions such as high temperature. Ion polymerization can use lithium salt or lithium metal as an initiator at room temperature, thereby effectively avoiding the introduction of impurities. Up to now, researchers have made considerable research progress in the construction of solid polymer electrolytes by ion-initiated