High-performance aqueous asymmetric supercapacitors based on a cathode of carbon nanotube/NiCo2O4 nanograss-supported MnCoP nanosheets on Ni foam

Abstract

In this paper, we report a cathode with the good comprehensive electrochemical performance by electrochemically growing MnCoP nanosheets on NiCo2O4 nanograss hydrothermally grown on carbon nanotube (CNT)-coated Ni foam. A capacitance of 4787.3 mF cm−2 at 1 mA cm−2, high rate performance (3126.2 mF cm−2 at 30 mA cm−2), as well as good cycle stability is delivered by the cathode. By employing this cathode, the anode of activated carbon on carbon cloth, and the electrolyte of 2 M KOH aqueous solution, we assembled an aqueous asymmetric supercapacitor, which exhibits an energy density of 0.390 mWh cm−2 at 0.825 mW cm−2 and good cycle stability of 85.7 % capacitance retention after 20,000 cycles at 10 mA cm−2.