Strain-insensitively stretchable yarn electrodes for self-powered sensing textiles

Self-powered textiles integrated energy storage and sensors have generated growing interest in the area of wearable electronics. However, most current elastic supercapacitors designed for wearable self-powered systems exhibit insufficient strain-insensitivity to accommodate the intricate deformations of the human body. In this work, MXene is being explored for strain-insensitive one-dimensional (1D) energy storage devices by introduction of reduced graphene oxide (rGO) and polypyrrole (PPy) to create a composite yarn electrode via pre-stretching in-situ polymerization strategy, which also can be integrated into self-powered wearable sensing textile. The yarn electrodes incorporating rGO effectively minimize crack formation at high strains, showcasing an enhanced capacitance of 51.35 mF·cm⁻¹ and retaining ~95% of their original capacitance at 200% strain. The resulting symmetric supercapacitor exhibits strain insensitivity up to 200% and delivers stability of electrochemical behavior under real-time dynamic stretching conditions independent of the strain rate. Furthermore, yarn pressure sensing leveraging the resistance change of stripe coating structure achieves high sensitivity of 1.08 kPa⁻¹. Therefore, the integrated self-powered textiles allow convenient use for transmission of Morse code real-time and provide a feasible routine burgeoning transformative telemedicine diagnosis.