Novel Thermoplastic Polyurethanes Enable Biaxially Stretchable Conductor for Supercapacitors with High Areal Capacitance

Stretchable supercapacitors are essential components in wearable electronics due to their low heat generation and seamless integration capabilities. Thermoplastic polyurethane elastomers, recognized for their dynamic hydrogen-bonding structure, exhibit excellent stretchability, making them well-suited for these applications. This study introduces fluorine-based interactions in the hard segments of thermoplastic polyurethanes, resulting in polyurethanes with a low elastic modulus, high fracture strength, exceptional fatigue resistance, and self-healing properties. By utilizing these polyurethanes as binders and meshed fabric as scaffolds, we developed highly stretchable conductors. These conductors maintain low resistance (∼26 ohms) under biaxial stretching and exhibit a stable bidirectional conductivity after 1600 stretching cycles. The fabricated supercapacitor electrode, incorporating fabric current collectors, polyurethane, and MXene, achieves an ultrahigh areal specific capacitance of 7200 mF cm^-2 and retains 100% capacity after 2300 cycles. This material design strategy offers significant potential in elastic materials, stretchable conductors, and high-performance energy storage for wearable electronics.