A Wearable Supercapacitor Based on Conductive PEDOT:PSS‐Coated Cloth and a Sweat Electrolyte

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.