MnCo2S4 nanosheet arrays modified with vermicular polypyrrole for advanced free-standing flexible electrodes

Abstract

Flexible electrodes are pivotal to flexible supercapacitors (FSCs), however, there is still plenty of room for the development of flexible electrodes with satisfactory mechanical properties and capacitive performances simultaneously. To this end, MnCo2S4 nanosheet arrays modified with vermicular polypyrrole (MCS@PPy) are grown on activate carbon cloth (ACC) by solvothermal and electropolymerization technologies in this work. Benefiting from the cooperative effect between MnCo2S4 and PPy, the MCS@PPy60/ACC composites exhibit a high areal capacitance of 780.8 mF cm−2 (321.3 mAh cm−2) at 1 mA cm−2 and rate performance (72.1% from 1 to 20 mA cm−2). Furthermore, the FSCs are constructed with the as-prepared MCS@PPy60/ACC electrodes as positive electrodes and PPy/ACC electrodes as negative electrodes. The FSCs show a high energy density of 0.059 mWh cm−2 at 0.7 mW cm−2, ultrahigh cycling stability (98.2% retention after 10,000 cycles) and impressive flexibility. This work provides enlightenment for the in-depth study of high-performance free-standing flexible electrodes in FSCs.