Facile synthesis of ZnCo2O4@FeCoNi-LDH electrode with hierarchical structure for high areal capacitance

The development of high areal capacitance electrode materials remains a critical challenge in supercapacitor technology. This study implements a substrate-free powder growth strategy to synthesize ZnCo₂O₄@FeCoNi-LDH micro-nano powders with core-shell heterostructures via controlled solvothermal synthesis. Through stepwise crystallization, ZnCo₂O₄ nanowires were initially constructed as conductive scaffolds, followed by in situ growth of FeCoNi-LDH nanosheets to form hierarchical porous architectures. Leveraging Zn²⁺'s strong electronegativity and spinel-phase stability, the composite demonstrates optimized pore size distribution (1.5 nm reduction vs. pristine material) and ultrahigh specific surface area (282.4 m²/g). Synergized with Fe/Co/Ni multimetallic redox centers, these structural advantages significantly enhance electron transport efficiency and cycling endurance. As an electrode, it achieves 1937 F g^-1 at 1 A g^-1 areal capacitance of 12.92 F cm^-2 with 97.69% capacity retention after 6000 cycles. When assembled into nickel foam (NF)-configured asymmetric devices, the system delivers 96.87 Wh kg^-1 energy density at 300 W kg^-1 power density. This powder-based synthetic paradigm establishes a scalable pathway for high-stability composite electrodes.