Rational design of KCu7S4@NiCo2O4 in-situ growth on nickel foam for high performance supercapacitor electrode

Abstract

The application of NiCo2O4 as electrode materials for supercapacitors has attracted widespread attention. However, pristine NiCo2O4 always suffer from poor electrical conductivity and rate performance that limit their electrochemical performance in supercapacitors. In order to overcome the deficiencies of NiCo2O4, in this study, we successfully synthesized KCu7S4@NiCo2O4 core–shell structure in-situ grown on Ni foam with good electrochemical performance. The morphologies of KCu7S4@NiCo2O4 composite could be controlled by electrochemical deposition time. According to the electrochemical testing results, an optimal composite was obtained with the deposition time of 10 min, and the corresponding KCu7S4@NiCo2O4 composite possessed the high specific capacitance of 18.4 F cm−2 (2008 F g−1) at a current density of 3 mA cm−2 and good cycling stability (80% capacitance retention after 4000 cycles at a current density of 40 mA cm−2). Moreover, the investigation demonstrates the great potential application of KCu7S4 @NiCo2O4 in supercapacitor. The asymmetric supercapacitor fabricated with KCu7S4@NiCo2O4 and activated carbon delivers a high energy density of 125.56 Wh kg−1 at the power density of 105.5 W kg−1.