Strain compensation strategy: Construction of dual metal-organic framework derived nickel zinc oxide/nickel cobalt phosphide hybrid dual-transition metal heterostructure for high-performance supercapacitors.

Transition metal-based compounds have emerged as a research hotspot for supercapacitor cathode materials owing to their exceptional electrochemical performance. However, they still suffer from intrinsic performance limitations. Currently, researchers have successfully integrated the advantageous properties of different components by constructing single-transition metal heterostructures. Nevertheless, such heterostructures encounter challenges such as interfacial stress concentration and dislocation defects owing to lattice mismatch between components. To address these issues, this study demonstrates the preparation of two-dimensional (2D) lamellar nickel zinc oxide/nickel cobalt phosphide (Ni2Zn6O4/NiCoP) with a mixed dual-transition metal heterostructure using dual metal-organic frameworks (dual-MOFs) as precursors. This structural design maintains the exceptional surface area characteristic of the parent materials while addressing inherent limitations via component-interaction-driven optimization. Moreover, strain compensation significantly optimizes lattice parameter matching. Density functional theory (DFT) calculations demonstrate that the Ni2Zn6O4/NiCoP heterostructure exhibits exceptional OH- adsorption capability (E(HO-Ni2Zn6O4/NiCoP) = -10.8 eV), significantly enhancing both power and energy densities. Density of states (DOS) analysis further confirms the synergistic effects between components effectively elevate valence electron concentration, thereby enhancing capacitive performance and electrical conductivity.