Facile construction of a MgCo2O4@NiMoO4/NF core–shell nanocomposite for high-performance asymmetric supercapacitors

Abstract

The development of all-solid-state asymmetric supercapacitors (ASCs) is a hot topic, and the main goal of researchers is to develop better electrode materials. In this work, a double urchin-like hierarchical MgCo₂O₄@NiMoO₄ (MCN) core–shell nanomaterial is successfully synthesized on foam nickel (NF) by a two-step simple and effective hydrothermal method. It displays good physical, chemical structure and excellent electrochemical properties, which is mainly due to the synergistic effect of both MgCo₂O₄ and NiMoO₄ electrode materials. The MCN-2 electrode material exhibits a high specific capacitance of 1775 F g⁻¹ at 1 A g⁻¹ and an excellent cycling stability of 74.7% after 5000 cycles. In addition, the MCN-2//AC ASC device is assembled using the MCN-2 electrode material as the positive electrode and activated carbon (AC) as the negative electrode. Obviously, the MCN-2//AC ASC device possesses an excellent cycling stability of 71.7% after 10 000 cycles and a high energy density of 37.5 W h kg⁻¹ at the power density of 480 W kg⁻¹. Simultaneously, it can supply power for light emitting diodes (LEDs) and motors successfully. The above results manifest that the MCN-2//AC ASC device is a good energy storage device, and it has great potential in practical applications.