Fe ³⁺ /Mo ⁶⁺ -Codoped ZnWO ₄ @rGO Supercapacitor Electrode Material with Defect–Electron Transport–Interface Trinity Regulation and Its Electrochemical Energy Storage Performance

In order to improve the low conductivity, slow reaction kinetics, and poor mechanical stability of zinc tungstate (ZnWO4) as a supercapacitor electrode material, the strategy of hydrothermal synthesis of Fe3+/Mo6+-codoped ZnWO4 composite graphene oxide (FM-ZWO@rGO) was proposed. Among them, Fe3+ doping induced a high concentration of oxygen vacancies ( VO••, concentration increased by 8.33%), which significantly improved the redox activity of the material. Mo6+ doping reduces the charge transfer energy barrier by introducing low-level orbitals to regulate the energy level positions of the valence band (VB) and conduction band (CB). The two synergistically further inhibit the longitudinal growth of the crystal, form a high-specific-surface-area spherical morphology and defect network, and optimize the ion diffusion path. In terms of improving cycle stability, rGO is anchored by chemical bonding and layered-coated with doped particles to buffer the volume strain during the cycle, effectively inhibiting structural collapse and active material dissolution. The electrochemical performance of ZnWO4 was enhanced by the trinity of defect engineering–electron transport optimization–interface reinforcement, so that F0.03M0.03-ZWO@rGO exhibited the ideal specific capacity (1 A g–1 1027.05 F g–1) and cycle stability (20 A g–1 101.2% after 5000 cycles). It shows the great potential of the trinity strategy to improve the electrochemical performance of supercapacitors and provides an idea for the preparation of high-performance bimetallic oxide electrode materials.