Strain-insensitive yarn supercapacitor based on conductive polypyrrole-bridged MOF nanoarrays

Endowed with remarkable flexibility and weavability, yarn-based supercapacitors hold substantial promise as energy-storage devices for wearable electronic textiles. However, current supercapacitors lack stretchability and struggle to maintain structural integrity and electrochemical stability under the complex, multi-dimensional deformations caused by human movement, which severely limits their practical application in wearable electronics. This study prepared a strain-insensitive yarn supercapacitor with a crinkled structure using a pre-stretched interfacial polymerization method through structural design and material selection. The supercapacitor demonstrates a high area capacitance of 27.9 mF cm^-2 (40.13 F g^-1), a power density of 37.42 μW cm^-2 (54.26 W kg^-1) and an energy density of 2.2 μWh cm^-2 (3.2 Wh kg^-1). Moreover, it retains 91.19% relative to its original capacitance when subjected to a high static stretch of 200% and still maintains 87.5% capacitance after 3000 dynamic stretching cycles (at a stretching rate of 10% s^-1). These results clearly illustrate its excellent strain-insensitivity and underscore its significant potential as an energy storage platform for wearable electronics.