Edinburgh Napier University

  A sweat-based flexible supercapacitor (SC) for self-powered smart textiles and wearable systems is presented. The developed SC uses sweat as the electrolyte and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the active electrode. With PEDOT:PSS coated onto cellulose/polyester cloth, the SC shows specific capacitance of 8.94 F g−1 (10 mF cm−2) at 1 mV s−1. With artificial sweat, the energy and power densities of the SC are 1.36 Wh kg−1 and 329.70 W kg−1, respectively for 1.31 V and its specific capacitance is 5.65 F g−1. With real human sweat the observed energy and power densities are 0.25 Wh kg−1, and 30.62 W kg−1, respectively. The SC performance is evaluated with different volumes of sweat (20, 50, and 100 µL), bending radii (10, 15, 20 mm), charging/discharging stability (4000 cycles), and washability. With successful on-body testing, the first demonstration of the suitability of a sweat-based SC for self-powered cloth-based sensors to monitor sweat salinity is presented. With attractive performance and the use of body fluids, the presented approach is a safe and sustainable route to meet the power requirements in wearable systems.