Construction of 3D hierarchical Co3O4@Ni(OH)2 core-shell heterostructures aligned on Ni foam for high performance supercapacitor

In this study, the three-dimensional (3D) architectures of Co₃O₄@Ni(OH)₂ core–shell heterostructures (CSHs) were engineered on nickel foam (NF) via a facile two-step hydrothermal route. The integrated structure of the resulting material enables its use as a binder-free supercapacitor electrode with significantly improved electrochemical properties. It achieves a superior specific capacitance ( C s ) of 2332.5 F g⁻¹ at 1 A g⁻¹ and 2350 F g⁻¹ at 2 A g⁻¹ within a potential window of 0–0.40 V (vs. SCE), along with exceptional cycling durability evidenced by 82.4 % capacity retention over 10000 cycles. The assembled Co₃O₄@Ni(OH)₂ CSHs/NF//CNTs asymmetric supercapacitor (ASC) exhibits a high energy density of 65.8 Wh kg⁻¹ (1600 W kg⁻¹) and exceptional long-term stability, retaining 82.5 % of its initial capacitance with nearly 100 % coulombic efficiency after 10000 cycles. The exceptional performance arises from a unique 3D hierarchical architecture that ensures high conductivity, offers abundant active sites, and fosters a synergistic effect between the wire-like Co₃O₄ core and the ultrathin Ni(OH)₂ shell. This work opens a new avenue for the rational design of high-performance electrode materials for advanced energy storage systems.