Interface engineered hollow Co3O4@CoNi2S4 nanostructure for high efficiency supercapacitor and hydrogen evolution
Zhichang Duan, Xue-Rong Shi, Chunyan Sun, Wensong Lin, Simin Huang, Xiangrui Zhang, Mengru Huang, Zhi Yang, Shusheng Xu
Abstract
Constructing interface is an efficient strategy to develop high-performance nanomaterials for energy storage and conversion. By adopting the combined strategies of interface engineering and constructing specific nanostructures, we fabricated a bifunctional hollow Co3O4@CoNi2S4 core-shell with dual interfaces for high-performance hybrid supercapacitor (HSC) and hydrogen evolution reaction (HER). The free-standing Co3O4 nanotube@nanosheets core was first obtained by calcinating ZIF-67 nanorods with homojunction interface on carbon cloth (CC) and then combined with the CoNi2S4 shell to improve the conductivity, as confirmed by first-principle calculations. The synthesized Co3O4@CoNi2S4-20/CC with surface holes and hollow cores exhibits a capacity of 1079 C g−1 (i.e., 299.7 mA h g−1, capacitance of 1798 F g−1) at 1 A g−1 and remains 841 C g−1 at 10 A g−1. The Co3O4@CoNi2S4-20/CC//AC HSC delivers an excellent energy density of 58.1 Wh kg−1 at the power density of 799.9 W kg−1 and excellent cycle stability. Additionally, the fabricated Co3O4@CoNi2S4-20/CC requires an overpotential of 185 mV at 10 mA cm−2 in 1 M KOH for HER. This work shed a light on the rational design of bifunctional electrodes for high-performance supercapacitor and HER.