Preparation and Electrochemical Performance of Multilayer Core-Shell Co₃O₄@NiCo₂O₄/MXene

Supercapacitors offer distinct advantages including high power density, fast charging and discharging capability, and excellent cycle longevity, yet their structural stability remains a critical challenge for practical applications. Herein, a core-shell structured Co₃O₄@NiCo₂O₄ was constructed on MXene surface via Ni²⁺-assisted ion exchange and controlled annealing using a template precursor method with ZIF-67/MXene as the precursor. The microstructural characteristics and electrochemical energy storage performance of the as-prepared material were systematically investigated. Electrochemical measurements reveal that the as-prepared electrode delivers a specific capacitance of 1115.31 F·g⁻¹ at 1 A·g⁻¹ and retains 86.37% of its initial capacitance after 4000 cycles at 5 A·g⁻¹. Furthermore, the asymmetric supercapacitor assembled with this electrode achieves an energy density of 88.90 Wh·kg⁻¹ at a power density of 748.42 W·kg⁻¹, with a capacitance retention of 89.06% over 4000 cycles at 10 A·g⁻¹. This design synergistically integrates the MOF-derived porous architecture with the highly conductive MXene network, offering a promising route for the development of advanced pseudocapacitive electrode materials.