Preparation and application on core-shell nanocomposite MgCo2O4@MnMoO4 as the electrode of supercapacitors

Supercapacitors have attracted significant attention due to their high power density and stable cycle life. MgCo₂O₄@MnMoO₄ (MCMn) is successfully grown on nickel foam for the first time using a two-step simple hydrothermal method. SEM results indicate a core-shell structure with nano-needle MgCo₂O₄ as the core and nanosheet MnMoO₄ as the shell, enhancing its electrochemical properties. Moreover, MCMn-8h has a BET-specific surface area of 57.05 m²·g⁻¹ and an average pore size of 5.99 nm. The unique structure and large specific surface area provide the basis for the performance of the materials. From the test results of the materials, the MCMn-8h electrode has a 2381.8 F·g⁻¹ (1 A·g⁻¹) specific capacitance, and the initial capacity retention is 96.83 % (10,000 cycles，8 A·g⁻¹). The materials show excellent stability. Additionally, the MCMn-8h//AC (ASCs) device has a Coulombic efficiency of 93.3 %, an energy density of 31.9 Wh·kg⁻¹ (375 W·kg⁻¹), and a capacitance retention of 76.5 % (5000 cycles, 5 A·g⁻¹). MCMn-8h retains an intact core-shell structure after cycling, demonstrating excellent electrochemical energy storage properties and potential for supercapacitor applications.