The Polymer Society of Korea

Abstract

Next-generation high–energy-density lithium-ion batteries are increasingly required for a wide range of applications. However, the implementation of high-voltage cathodes and high-capacity anodes induces interfacial instability at the electrode–electrolyte interface, thereby limiting the cycle life and safety of the batteries. In this study, to enhance interfacial stability and lithium-ion transport properties, a polythiophene copolymer synthesized from functionalized thiophene and unsubstituted thiophene is introduced as an electrolyte. The polar functional side chains form ion-conductive domains, while the incorporation of unsubstituted thiophene suppresses excessive coordination between lithium ions and the functional side chains. Furthermore, the planar thiophene backbone promotes chain alignment and layered structure formation, contributing to the formation of stable CEI and SEI layers at the electrode surface.