Ion-Conductive Vitrimers Based on Backbone-Type Triazolium Poly(Ionic Liquid)s: Counterion-Dependent Dynamics and Backbone Flexibility

High Resolution Image Download MS PowerPoint Slide To simultaneously achieve high ionic conductivity and recyclability, vitrimers were prepared using backbone-type triazolium poly(ionic liquid)s (TPILs) that integrate ionic transport and dynamic network rearrangement via trans- N -alkylation. TPIL elastomers bearing I –, BF 4 –, PF 6 –, and TFSI – counteranions were synthesized from “clickable” ionic liquid monomers, and their glass transition temperature ( T g ), ionic conductivity, and vitrimeric dynamics were compared. Only the I – -based network exhibited stress relaxation at 170 °C, indicating that nucleophilic anions are important for bond exchange. However, a trade-off was observed between ionic transport and dynamic network rearrangement. We overcome this trade-off by mixing anions. Mixed-anion TPIL elastomers using I – and TFSI – exhibited lower T g and higher ionic conductivity than I – -based elastomer, while still maintaining vitrimer-like relaxation. Rheological analysis revealed a decoupling between segment relaxation and bond exchange dynamics in vitrimer-like elastomers. The design combining flexible polymer backbones and mixed-anion engineering can create recyclable, highly conductive polymer electrolyte networks.