Enabling fast ion diffusion and charge transfer in NiCo₂O₄/C/MnO₂ hollow nanocages via interfacial electronic...

In this study, we synthesized a ternary NiCo₂O₄/C/MnO₂ nanocage structure using PBA as a template, aiming to enhance the electrochemical performance of supercapacitor electrode materials. The unique design integrates NiCo₂O₄, carbon, and MnO₂ into a hollow nanocage architecture, which synergistically improves conductivity, optimizes electrochemical active sites, and enhances structural stability. The incorporation of carbon significantly boosts electrical conductivity, while the ternary composition provides abundant redox reaction sites, facilitating efficient charge transfer and ion diffusion. The hollow nanocage structure not only offers ample space for electrolyte penetration and storage but also accommodates volume changes during charge-discharge cycles, ensuring excellent cyclic stability. The NiCo₂O₄/C/MnO₂ electrode exhibits a high specific capacitance of 725.1C g^-1. The fabricated supercapacitor achieves an energy density of 82.5 Wh kg^-1 at 800 W kg^-1 with 70.5 % capacitance retention after 8000 cycles. Furthermore, the device demonstrates excellent practical feasibility with slow self-discharge (50 % voltage drop after 29.4 h) and ultralow leakage current (∼1.1 μA).