Interface engineered hollow Co3O4@CoNi2S4 nanostructure for high efficiency supercapacitor and hydrogen evolution

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 Co 3 O 4 @CoNi 2 S 4 core-shell with dual interfaces for high-performance hybrid supercapacitor (HSC) and hydrogen evolution reaction (HER). The free-standing Co 3 O 4 nanotube@nanosheets core was first obtained by calcinating ZIF-67 nanorods with homojunction interface on carbon cloth (CC) and then combined with the CoNi 2 S 4 shell to improve the conductivity, as confirmed by first-principle calculations. The synthesized Co 3 O 4 @CoNi 2 S 4 -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 Co 3 O 4 @CoNi 2 S 4 -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 Co 3 O 4 @CoNi 2 S 4 -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. Interface engineered hollow Co 3 O 4 @CoNi 2 S 4 nanostructure for high efficiency supercapacitor and hydrogen evolution.