Self-supported Ni (OH)2-templated growth of Mo-doped CrNi-MOFs toward Sulfurized heterointerfaced nanospheres for high-energy-density supercapacitors

Metal-organic frameworks (MOFs) have emerged as promising electrode materials for supercapacitors, owing to their tunable pore architectures, abundant ion diffusion pathways, and accessible active sites. However, their inherent low conductivity and restricted rate capability limit the breakthrough of practical electrochemical performance. Herein, a three-step hydrothermal synthesis strategy is developed to fabricate a three-dimensional heterostructure by in situ growth of Ni (OH)₂ nanosheet arrays on nickel foam as a conductive scaffold, followed by in situ deposition of Mo-doped CrNi-MOF (MIL series), achieving a porous honeycomb-like architecture (HC₂N₁M₁). Subsequent sulfidation treatment further converts the hybrid structure into a porous nanosphere-based heterostructure (HC₂N₁M₁-S₁₂₀), demonstrating controlled morphological evolution. The optimized HC₂N₁M₁-S₁₂₀ material delivers a high specific capacitance of 956.7 C g^-1 at 1 A g^-1 and demonstrates exceptional cycling stability with 76 % capacity retention over 8000 cycles, benefiting from its unique structural hierarchy and multiple charge transport pathways. Furthermore, the asymmetric supercapacitor device assembled with this electrode (HC₂N₁M₁-S₁₂₀//AC) achieves a remarkable energy density of 58.4 Wh kg^-1 at a power density of 800 W kg^-1, showcasing its potential for high-performance energy storage systems. This study has demonstrated a synergistic strategy combining elemental doping and multidimensional structural engineering, thereby paving a new pathway for developing advanced electrode materials toward high-performance supercapacitors through rational material design.