Novel Thermoplastic\nPolyurethanes Enable Biaxially\nStretchable Conductor for Supercapacitors with High Areal Capacitance

Stretchable supercapacitors are essential components\nin wearable\nelectronics due to their low heat generation and seamless integration\ncapabilities. Thermoplastic polyurethane elastomers, recognized for\ntheir dynamic hydrogen-bonding structure, exhibit excellent stretchability,\nmaking them well-suited for these applications. This study introduces\nfluorine-based interactions in the hard segments of thermoplastic\npolyurethanes, resulting in polyurethanes with a low elastic modulus,\nhigh fracture strength, exceptional fatigue resistance, and self-healing\nproperties. By utilizing these polyurethanes as binders and meshed\nfabric as scaffolds, we developed highly stretchable conductors. These\nconductors maintain low resistance (∼26 ohms) under biaxial\nstretching and exhibit a stable bidirectional conductivity after 1600\nstretching cycles. The fabricated supercapacitor electrode, incorporating\nfabric current collectors, polyurethane, and MXene, achieves an ultrahigh\nareal specific capacitance of 7200 mF cm<sup>–2</sup> and retains\n100% capacity after 2300 cycles. This material design strategy offers\nsignificant potential in elastic materials, stretchable conductors,\nand high-performance energy storage for wearable electronics.