Enhancing High Volumetric Energy Density of Supercapacitors through Diatomic Reconstruction of Layered Double Hydroxides

Double atom regulation and synergistic phosphorus doping and oxygen vacancy (O_V) engineering are effective strategies for optimizing the electronic structure of layered double hydroxides (LDHs). In this study, a self-supporting P-doped O_V-(Co_0.5Ni_0.5)₃V₂O₈ electrode with interpenetrating carbon nanotube networks was synthesized via cation/anion co-reconstruction. Leveraging vanadium's high valence states, the dual-atom system creates a microporous architecture that enables precise charge redistribution, enhancing both electrical conductivity and OH^- adsorption capacity. Density functional theory confirms that P-O_V synergy reduces charge transfer resistance while optimizing ion diffusion pathways and charge storage kinetics. The optimized electrode achieves outstanding performance: 3807.9 F cm^-3 volumetric capacitance at 1 A g^-1 and exceptional cycling stability (100% capacity retention over 10000 cycles). Assembled asymmetric supercapacitors deliver 158.1 Wh L^-1 energy density at 992 W L^-1 power density, surpassing most reported LDH-based devices. This dual-atom charge redistribution mechanism establishes a universal paradigm for designing high-capacity electrodes, addressing critical challenges in energy storage materials through simultaneous electronic structure modulation and microstructural stabilization.