Impact of Zwitterionic Polymer Chemistry and Alkali Metal Identity on the Ion Transport Dynamics of Polymer-Supported Ionic Liquid Electrolytes

Zwitterionic (ZI) polymers have emerged as promising candidates for polymer-supported ionic liquid electrolytes due to their ability to balance ion dissociation and mechanical stability through internal dipole–ion interactions. Using equilibrium and nonequilibrium molecular dynamics simulations, we investigate how polymer chemistry and alkali metal identity regulate ion transport in poly(MPC)- and poly(CBMA)-based ionogels containing LiTFSI or NaTFSI salts in BMP-TFSI. Li^⁺ ions exhibit stronger coordination with ZI polymers than Na^⁺, leading to reduced Li^⁺–TFSI^⁻ pairing and enhanced ionic conductivity. Poly(CBMA) ionogels display faster ion dynamics and greater ion–polymer decoupling relative to poly(MPC) systems. Radial distribution and coordination analyses reveal that optimal cation–polymer and cation–anion interactions govern the observed conductivity trends. These insights demonstrate how zwitterionic polymer chemistry can be leveraged to design ionogels with tailored ion transport properties for advanced electrochemical energy storage applications.