Biomechanical Energy‐Harvesting Wearable Textile‐Based Personal Thermal Management Device Containing Epitaxially Grown Aligned Ag‐Tipped‐NixCo1−xSe Nanowires/Reduced Graphene Oxide

Abstract Energy consumption is increasing with the rapid growth of externally powered electronics. A vast amount of energy is needed for indoor heating, and body heat is dissipated to the surroundings. Recently, wearable heaters have attracted interest for their efficiency in providing articular thermotherapy. Herein, the fabrication of a personal thermal management device with a self‐powering ability to generate heat through triboelectricity is reported. Composites are prepared with vertically aligned silver tipped nickel cobalt selenide (Ag@Ni x Co 1− x Se) nanowire arrays synthesized on the surface of woven Kevlar fiber (WKF) sheets and reduced graphene oxide (rGO) dispersed in polydimethylsiloxane (PDMS). The Ag@Ni x Co 1− x Se with rGO induces effective Joule heating in the composites (79 °C at 2.1 V). The WKF/Ag@Ni x Co 1− x Se/PDMS composite shows higher infrared reflectivity (98.1%) and thermal insulation (54.8%) than WKF/PDMS. The WKF/Ag@Ni x Co 1− x Se/PDMS/rGO composite has an impact resistance and tensile strength that are 152.2% and 92.1% higher, respectively, than those of WKF/PDMS. A maximum output power density of 1.1 mW cm −2 at a low frequency of 5 Hz confirms efficient mechanical energy harvesting of the composites, which enables self‐heating. The high flexibility, breathability, washability, and effective heat generation achieved during body movement satisfy the wearability requirement and can address global energy concerns.