Boosting Energy Efficiency of Nickel Cobaltite via Interfacial Engineering in Hierarchical Supercapacitor Electrode

Abstract

Hybrid electrodes with electroactive components on conductive substrates have been demonstrated to be an effective strategy to achieve high energy and power density in supercapacitors. However, the mismatch of interface property could be a huge hurdle to further improve energy storage performance and long-term stability. In this work, an interfacial metal seeding approach has been developed targeting strengthening of the interfacial interaction between electroactive NiCo2O4 nanostructure and carbon substrate as well as to promote electron transfer across the interface. By implanting low-concentration nickel (Ni) nanoparticles at the interface, the electrochemical capacitance of NiCo2O4 was boosted up to 2367 F/g at a current density of 1 A/g in a symmetric two-electrode configuration, which is about 2 times higher than the capacitance obtained from the electrode without metal seeds. The Ni seeds also contribute to an excellent cycling retention of >96% after 5000 cycles, where only 65% capacitance was ret...