A wearable, disposable paper-based self-charging power system integrating sweat-driven microbial energy harvesting and energy storage devices

Abstract

Microbial fuel cell (MFC) technology is constantly pushing its boundaries and advancing in unexpected ways. Integrating non-toxic, storable, spore-forming bacterial cells into a flexible, disposable paper-based MFC platform provides a new route for powering single-use, sweat-based, wearable devices. Even for one-time or short-term operations, however, the MFC performance remains insufficient as an integrated wearable power source that is reliable and practical. This work demonstrates the first example of wearable, sweat-based, disposable self-charging power paper integrating three MFCs as an energy harvester and a solid-state supercapacitor (SC) as an energy storage device. By printing energy harvesting and storing functionalizes on the same piece of paper, the design and fabrication of the system can be revolutionarily simplified while its flexible, wearable, all-in-one papertronic platform will conform to the skin. Horizontal MFC and planar interdigitated SC devices are easily integrated into a single sheet of paper. This hybrid self-powered system generates an outstanding 4 µW/cm2 and 37 µA/cm2 from sweat, stores an excellent 9.81 mF of energy, demonstrates stable capacitive behavior for more than 100 cycles, and possesses superior self-charging characteristics as it can produce a constant discharge of 5.53 µAh. As a proof of concept, the system successfully powered an on-chip light-emitting diode (LED).