Weaving fiber-based triboelectric nanogenerators and yarn-based sweat-activated batteries for dry-wet bimodal power supply in textile electronics

Textile-based energy systems, which can provide sustainable power in both dry and wet conditions, are ideal for wearable devices, especially electronic textiles used for motion monitoring, and have attracted much interest in recent years. In this work, we developed a hybrid energy fabric woven with fiber-based triboelectric nanogenerators (F-TENGs) and yarn-based sweat-activated batteries (Y-SABs) to achieve a dry-wet bimodal power supply. Single-electrode core-sheath F-TENGs were fabricated as dry-state energy harvesters, which could respond sensitively to repeated skin contact to produce transient spikes of open-circuit voltage and short-circuit current at 30 V and 2 mu A, respectively. Since the wetting of the F-TENGs could result in a remarkable degradation of the triboelectric performance, coaxial Y-SABs with the output voltage of 0.58 V (external load=2 k Omega) were manufactured to supply power in the wet state sustainably. Both devices withstood 1500 times bending/twisting and 20 times machine washing. The F-TENGs and the Y-SABs were integrated with the conventional weaving technique to obtain a plain structured fabric, in which the TENG and SAB regions could successively generate electricity to power electronic devices under repeated skin contacts in the dry state and NaCl-solution activation in the wet state, respectively, without affecting each other. The hybrid energy fabric was further integrated into a shoe insole and a T-shirt for the on-body trials. During the volunteer's running process, the system could provide electricity to charge a capacitor or illuminate LEDs in sweatless and sweaty conditions, demonstrating its great potential as a reliable and sustainable dry-wet bimodal power source in wearable applications.