上海科技大学知识管理系统

The low mechanical performance and high flammabilityof gel polymerelectrolytes limit their application. Here, we prepare a high-strengthand nonflammable polymer Li-SPEEK (lithium sulfonated polyetheretherketone)to modify PEG (polyethylene glycol) and construct a PEG-Li-SPEEK cross-linkednetwork as a polymer electrolyte matrix, with an overall improvementin electrochemical performance, mechanical properties, and flame retardancy.The PEG-Li-SPEEK-ls (PEG-Li-SPEEK cross-linked network after gelationof the liquid electrolyte) electrolyte achieves a conductivity of1.62 x 10(-4) S center dot cm(-1) at30 degrees C, a wider electrochemical window of 4.5 V vs Li+/Li, and a higher lithium-ion transference number compared to thePEG-ls electrolyte. The excellent mechanical properties allow thesymmetric cell-containing PEG-Li-SPEEK-ls electrolyte to exhibit bettercycling performance for over 300 h at a current density of 0.2 mA center dot cm(-2). The LFP/PEG-Li-SPEEK-ls/Li cells deliver a maximumdischarge capacity of 142.1 mAh center dot g(-1) with acapacity retention of 98.1% after 50 cycles at 0.5 C and the Coulombicefficiency remains above 99.5% throughout the cycling process. Inaddition, the good carbon formation properties of Li-SPEEK give theelectrolyte matrix satisfactory flame-retardant properties. Thus,we validate the excellent performance of Li-SPEEK for modifying conventionalpolymer electrolytes and improving their mechanical, electrochemical,and flame-retardant properties.