The Polymer Society of Korea

Abstract

Lithium-ion (LIB) and sodium-ion batteries (SIB) are widely used energy storage systems, offering high energy density and cyclability (LIBs), and cost-effectiveness and sustainability (SIBs). However, flammable liquid electrolytes pose safety risks, limiting large-scale use. Although flame-retardant additives have been explored, they often reduce performance. To address this, we propose rational design strategies for polymer and composite electrolytes to improve both safety and performance. First, a polymer electrolyte with optimized solvent and cation-coordinating matrix enhanced ion dissociation and conductivity. Second, a nonflammable polymer electrolyte with ion-conductive networks and a flame-retardant phosphate solvent suppressed decomposition and enabled efficient ion transport. Lastly, hybrid electrolytes combining polymers and ion-conductive oxides improved thermal and mechanical stability. Continuous oxide frameworks provided structural integrity and fast ion pathways.