Ni counterpart-assisted synthesis of nanoarchitectured Co3O4/CoS/Ni(OH)2@Co electrode for superior supercapacitor

Abstract High mass loading Co 3 O 4 /CoS-based composites are constructed on Co foam through a one-pot hydrothermal process. Most importantly, when a Ni foam acting as counterpart support is introduced, components, morphologies and structures of composite on Co substrate significantly change: Micro-sized Co 3 O 4 /CoS transforms into hierarchical Co 3 O 4 /CoS/Ni(OH) 2 nanocomposite. In addition, the areal loading of Ni counterpart-induced Co 3 O 4 /CoS/Ni(OH) 2 nanocomposite reaches 14.72 mg cm −2 , and it exhibits excellent electrochemical performances: Its electrode possesses an areal capacitance of 14768 mF cm −2 at a current density of 10 mA cm −2 and 95.8% capacitance retention after 10000 cycles, while its asymmetric supercapacitor successfully delivers an energy density of 25.4 Wh kg −1 at a power density of 81.8 W kg −1 (or 12.34 Wh kg −1 at a power density of 1632.9 W kg −1 ) and 90.8% capacitance retention after 20000 cycles at a current density of 200 mA cm −2 . Furthermore, two asymmetric supercapacitor devices connected in series easily drive a red light emitting diode. This work opens a new strategy in preparing ultrahigh areal capacitance supercapacitor electrodes.