Wearable Biosupercapacitor: Harvesting and Storing Energy from Sweat

Abstract This work demonstrates the first example of sweat‐based wearable and stretchable biosupercapacitors (BSCs), capable of generating high‐power pulses from human activity. The all‐printed, dual‐functional, conformal BSC platform can harvest and store energy from sweat lactate. By integrating energy harvesting and storage functionalities on the same footprint of a single epidermal device, the new wearable energy system can deliver high‐power pulses and be rapidly self‐charged by bioenergy conversion of sweat lactate generated from human activity while simplifying the design and fabrication. The mechanical robustness and conformability of the device are realized through island‐bridge patterns and strain‐enduring inks. The enhanced capacitance of the BSC is realized by the synergistic effect of carbon nanotube ink with electrodeposited polypyrrole on the anode and of porous cauliflower‐like platinum on the cathode. In the presence of lactate, the BSC shows high power in pulsed output and stable cycling performance. Furthermore, the wearable device can store energy and deliver high‐power pulses long after the perspiration stopped. The self‐charging hybrid wearable device obtained high power of 1.7 mW cm −2 in vitro, and 343 µW cm −2 on the body during exercise, suggesting considerable potential as a power source for the next generation of wearable electronics.