Bifunctional CuO@CoV layered double hydroxide (LDH) core–shell heterostructure for electrochemical energy storage and electrocatalysis

The state-of-the-art designing and development of materials is an inevitable prior step for an effective solution regarding energy resources. In the context of supercapacitors (SCs) and electrocatalysis, it remains a challenge to fabricate electrode materials with high specific capacitance, high conductivity and lower overpotential. Here, a core–shell structure is prepared via a facile two-step electrodeposition method using CuO core and electrodeposited binary CoV LDH as the shell and used as a SC electrode and an electrocatalyst. For comparison, the CuO and Cu@CoV LDH electrodes are also prepared using a similar method. The CuO@CoV LDH core–shell electrode exhibits an areal capacitance of 206 mF cm⁻² accompanied by an excellent stability of 88 % over 5000 cycles at a current density of 10 mA cm⁻². This areal capacitance is far better than that obtained for CuO (49 mF cm⁻²) and Cu@CoV LDH (58 mF cm⁻²) electrodes. The symmetric device is fabricated using core–shell heterostructure demonstrating an energy density of 62.8 mWh cm⁻² and power density of 985 mW cm⁻². Moreover, the CuO@CoV LDH core–shell structure demonstrates an excellent oxygen evolution reaction (OER) catalytic activity with an overpotential of 329 mV and a Tafel slope of 65 mV dec^-1. This study opens a new route for the fabrication of CuO@CoV LDH core–shell structure via facile electrodeposition method for the electrochemical energy storage and catalytic activity.