Dual Functional MXene-Based Bioanode for Wearable Self-Charging Biosupercapacitor.

As a reliable energy-supply platform for wearable electronics, biosupercapacitors combine the characteristics of biofuel cells and supercapacitors to harvest and store the energy from human's sweat. However, the bulky preparation process and deep embedding of enzyme active sites in bioelectrodes usually limit the energy harvesting process, retarding the practical power-supply sceneries especially during the complicated in-vivo motion. Herein, we design the MXene/single-walled carbon nanotube/lactate oxidase hierarchical structure as the dual-functional bioanode, which can not only provide the superior three-dimensional catalytic microenvironment for enzyme accommodation to harvest energy from sweat, but also offer the sufficient capacitance to store energy via the electrical double-layer capacitor. The wearable biosupercapacitor is fabricated to "island-bridge" structure with the composite bioanode, active carbon/Pt cathode, polyacrylamide hydrogel substrate and liquid metal conductor. In vivo test, the device exhibits an open circuit voltage of 0.48 V and the high power density of 220.9 μW cm -2 at 0.5 mA cm -2 . The compact conformal adhesion with skin is successfully maintained under stretching/bending conditions. After repeatedly stretching the devices, there is no significant power attenuation in pulsed output. The unique bioelectrode structure and attractive energy harvesting/storing properties demonstrate the promising potential of this biosupercapacitor as micro self-powered platform of wearable electronics. This article is protected by copyright. All rights reserved.