Morphology-controllable synthesis of rod-shaped CuO@Co3O4 derived from CuCo-MOF-74 for supercapacitors

Abstract

Transition metal oxides (TMOs) have excellent electrochemical properties. However, they are commonly associated with short cycle lives, agglomeration, and lower electrical conductivity. To ameliorate these drawbacks, porous rod-shaped CuO@Co₃O₄ has been synthesized through calcination with optimized oxidation temperature by using CuCo-MOF-74 as a template. Due to the porous structure, the CuO@Co₃O₄ electrode significantly increases the contact area with the electrolyte and greatly improves the reaction kinetics. As a result, the CuO@Co₃O₄ electrode exhibits excellent electrochemical performance with a specific capacitance of 545.5 F g⁻¹ at a current density of 1 A g⁻¹. The capacitance retention at 10 A g⁻¹ was 88.7% after 10 000 cycles. Furthermore, an asymmetric supercapacitor (SC) has been assembled with CuO@Co₃O₄ as the positive electrode and commercial reduced graphene oxide (RGO) as the negative electrode, and the device has exhibited an energy density of 38.2 W h kg⁻¹ at a power density of 1268.3 W kg⁻¹. Impressively, the capacitance retention remained 83.2% even after 10 000 cycles at a high current density of 10 A g⁻¹. This performance has demonstrated the potential of CuO@Co₃O₄ as an anode material for SCs.