Core–shell CuO@NiCoMn-LDH supported by copper foam for high-performance supercapacitors

Abstract

The core–shell structured CuO@NiCoMn-LDH electrode was synthesized by wet chemistry, calcination, and electrodeposition. The synergistic effect of CuO nanowires and NiCoMn-LDH nanosheets has a significant enhancement effect on electrode materials. At the same time, the Mn content plays a decisive role in regulating and optimizing the morphology and electrochemical performance of electrode materials. The optimized CuO@NiCoMn-LDH, a binder-free electrode, exhibits excellent electrochemical performance. It displays a high specific capacity of 2.66 mA h cm⁻² (20.7 F cm⁻², 336.71 mA h g⁻¹) at 10 mA cm⁻² and satisfactory cycling stability (under a current density of 30 mA cm⁻², after 3000 cycles, the capacity retention rate is 94.82%). In addition, an asymmetric supercapacitor (ASC) is built using the CuO@NiCoMn-LDH electrode as the positive electrode and Fe₃O₄@C/CuO electrode as the negative electrode to demonstrate its practical applicability in energy storage devices. At a power density of 4.79 mW cm⁻², the ASC device can achieve a maximum energy density of 2.67 mW h cm⁻². Two ASC devices are used as the power source of the light emitting diode (LED), which can emit light continuously for 15 minutes, showing great potential in energy storage device applications.