Engineering CoP/FeP4 heterostructures on epitaxially grown ultra-thin two-dimensional MOFs via competitive coordination for high-durability electrochemical supercapacitors

Two-dimensional (2D) ultra-thin structures represent ideal precursor materials for supercapacitors, owing to their large surface area that exposes abundant metal active sites and shortens ion diffusion pathways, thereby facilitating electrochemical reactions. Herein, a 2D Co MOF (urea) material with precisely defined geometries is constructed by urea molecule induced structural topology control and epitaxial growth. Urea participates in coordination competition, actively promoting the 2D growth of the materials. Through subsequent controlled phosphating, 2D/3D P-CM(urea)/CFP heterostructures are successfully fabricated. The designed heterostructures effectively regulate interfacial charge states, generating abundant active sites and accelerating charge transfer kinetics. The as-fabricated electrode material exhibits remarkable high specific capacitance of 2353.8 F g⁻¹ at a current density of 2 mA cm⁻² and excellent rate capability. Density functional theory calculations is performed to reveal the mechanism of enhanced electrochemical performance. The assembled P-CM(urea)/CFP//AC asymmetric supercapacitor presents outstanding electrochemical performance such as a high energy density of 41.9 Wh kg⁻¹ at a power density of up to 711.4 W kg⁻¹, and a remarkably high cycling stability of 95.1% capacitance retention after 10000 charge-discharge cycles. These findings highlight the effectiveness of integrating morphological and electronic modulation for material optimization in energy storage applications.