A quasi-solid-state supercapacitor based on waste surgical masks with high flexibility and designable shape

Abstract

A quasi-solid-state flexible symmetric supercapacitor (QFSSC) based on waste surgical masks (WSMs) with high electrochemical performance and high flexibility has been designed. The WSMs with three-layer construction have been fully utilized to fabricate the QFSSC. The two outer layers are served as the flexible substrate to achieve flexible electrodes by loading polypyrrole (PPy) microcones via electropolymerization, while the interlayer is immersed into hydrogel electrolyte to play the role as separator. The unique three-dimensional porous network of WSMs provides sufficient sites to load the active substance and endows the electrodes with numerous electron/ion transmission channels. The influences of electropolymerization time on the morphology of the PPy and electrochemical performance of the electrodes have been comprehensively studied. The as-prepared QFSSC shows the maximum specific capacitance of 219.1 mF cm−2 at 1 mA cm−2, energy density of 19.48 μWh cm−2 at 219.2 μW cm−2, and power density of 3.3 mW cm−2 at 15.2 μWh cm−2, as well as good cycling stability and excellent flexibility. The QFSSC even keeps high capacitance retention of 92.1% and 88.3% after 10,000 charge/discharge cycles and 100,000 bending cycles, respectively. Moreover, the electrode/device can be cut into designable shapes to meet the need of practical application. In addition, the as-prepared QFSSC displays a satisfactory self-discharge property. This work demonstrates an economical and environmental way to recycle the WSMs produced in large quantities, which may make a great contribution to the circular sustainability.