NiO@CoSe2 nanostructures for high-performance asymmetric supercapacitors and efficient electrocatalysts

It is very important to design bi-functional materials for sustainable energy storage and conversion. NiO electrodes are promising candidates for supercapacitors and electrocatalysts, but the poor cycling stability limits their practical applications. To solve this issue, we prepared core-shell structured NiO@CoSe2 samples by a multi-step hydrothermal protocol. They exhibit a specific capacitance of 1130 C g(-1) at a current density of 1 A g(-1). An asymmetric device was assembled using the obtained product as the cathode. It delivers an energy density of 103.8 W h kg(-1) at 2700 W kg(-1). As an electrocatalyst for hydrogen evolution reactions, the NiO@CoSe2 sample presents an overpotential of 82.8 mV@10 mA cm(-2) and a Tafel slope of 72.14 mV dec(-1), respectively.

Automated summary

Designing bi-functional materials is crucial for sustainable energy storage and conversion. NiO electrodes show promise as supercapacitors and electrocatalysts, but their poor cycling stability hinders practical applications. To address this, we prepared core-shell structured NiO@CoSe2 samples through a multi-step hydrothermal method. These samples exhibited a specific capacitance of 1130 C g(-1) at a current density of 1 A g(-1). The assembled asymmetric device using the obtained product as the cathode delivered an energy density of 103.8 W h kg(-1) at 2700 W kg(-1). As an electrocatalyst for hydrogen evolution reactions, the NiO@CoSe2 sample showed an overpotential of 82.8 mV@10 mA cm(-2) and a Tafel slope of 72.14 mV dec(-1), respectively.