Hierarchically Developed Ni(OH)₂@MgCo₂O₄ Nanosheet Composites for Boosting Supercapacitor Performance

MgCo₂O₄ nanomaterial is thought to be a promising candidate for renewable energy storage and conversions. Nevertheless, the poor stability performances and small specific areas of transition-metal oxides remain a challenge for supercapacitor (SC) device applications. In this study, sheet-like Ni(OH)₂@MgCo₂O₄ composites were hierarchically developed on nickel foam (NF) using the facile hydrothermal process with calcination technology, under carbonization reactions. The combination of the carbon–amorphous layer and porous Ni(OH)₂ nanoparticles was anticipated to enhance the stability performances and energy kinetics. The Ni(OH)₂@MgCo₂O₄ nanosheet composite achieved a superior specific capacitance of 1287 F g⁻¹ at a current value of 1 A g⁻¹, which is higher than that of pure Ni(OH)₂ nanoparticles and MgCo₂O₄ nanoflake samples. At a current density of 5 A g⁻¹, the Ni(OH)₂@MgCo₂O₄ nanosheet composite delivered an outstanding cycling stability of 85.6%, which it retained over 3500 long cycles with an excellent rate of capacity of 74.5% at 20 A g⁻¹. These outcomes indicate that such a Ni(OH)₂@MgCo₂O₄ nanosheet composite is a good contender as a novel battery-type electrode material for high-performance SCs.