Flexible quasi-3D zinc ion microcapacitor based on V2O5-PANI cathode and MXene anode

Zinc ion microcapacitors (ZIMCs) are ideal energy storage device candidates for wearable electronic devices based on the matching between battery-type electrodes and capacitor-type electrodes, making full use of the respective advantages of batteries and capacitors. Herein, three-dimensional (3D) networked reduced graphene oxide- aramid nanofiber (rGO-ANF) foams were prepared by gas foaming technology and a laser engraving process. This process is not only simple and facile, but also involves inexpensive equipment, and meets the requirements for large-scale industrial production. Moreover, rGO-ANF foam exhibits good mechanical properties and generates numerous pores in the same direction as the electrolyte transport pathway during foaming. Using this rGO-ANF foam as a substrate, MXene as capacitor-type electrode, and vanadium oxide-polyaniline composite as battery-type electrode, a ZIMC with both high mechanical properties and high energy storage capacity, was successfully prepared in this study. This ZIMC shows excellent capacitance density (584 mF⋅cm−2 at 0.4 mA⋅cm−2) and energy density (262.8 μWh⋅cm−2, 360.3 μW⋅cm−2). Furthermore, the integrated pressure sensing system built on this ZIMC could monitor human physiological signals in real time with high accuracy, sensitivity, and fast response, demonstrating the feasibility of building ZIMCs as functional devices in wearable electronic devices. This new ZIMC exhibits significant potential for future wearable electronic devices.