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

Abstract

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.