Stretchable Ionic Conductors: Balancing Mechanical Properties and Ionic Conductivity

Stretchable ionic conductors (SICs) have been the focus of recent research due to their potential in soft electronics, bioelectronics, and flexible energy devices. A key challenge in this field is achieving a good balance between ionic conductivity and mechanical robustness, particularly in solvent-free systems where durability and long-term stability are critical. Recent progress in elastomer-based SICs has demonstrated innovative strategies to enhance performance, including the use of dynamic cross-linking, supramolecular interactions, and phase-separated networks. Materials such as poly(ionic liquid)-based elastomers (PILs), polymerizable deep eutectic solvents (PDESs), and dual-network ionogels have emerged as promising candidates, offering high stretchability, tunable conductivity, and improved mechanical strength. This review provides an overview of the design strategies and key properties of SICs, focusing on the interplay between mechanical performance and ion-transport. By analyzing recent advances in material architecture, cross-linking chemistry, and ion transport mechanisms, we highlight promising approaches for optimizing SICs for the next generation of stretchable devices.