Fabrication of Ternary rGO/MnO2/ZIF 8 Composite Electrode through Electrophoretic Deposition Method for Supercapacitor Application

The development of high‐performance supercapacitor electrodes relies on materials that combine high electrical conductivity, large accessible surface area, and stable redox behavior. In this study, rGO/MnO₂/ Zeolitic Imidazolate Framework-8 (ZIF-8) composite electrodes were fabricated on nickel foam through a sequential electrophoretic deposition (EPD) technique. Graphene oxide was synthesized via the Tour method, MnO₂ was obtained through a co-precipitation process followed by calcination, and ZIF-8 was subsequently deposited to construct a ternary hybrid structure. Raman spectroscopy confirmed the formation of β-MnO₂ and rGO, with an increased I _D /I _G ratio (1.81), indicating higher defect density favorable for electrochemical activity. FESEM–EDX analysis revealed a hierarchical architecture composed of rGO nanosheets supporting MnO₂ nanoparticles and ZIF-8 crystals with uniform elemental distribution, confirming successful composite integration. Electrochemical characterization in 0.5 M Na₂SO₄ demonstrated that rGO/MnO₂/ZIF-8 electrode delivered the highest performance compared to pristine MnO₂ (17.19 F g⁻¹) and ZIF-8 (11.83 F g⁻¹), exhibiting a specific capacitance of 42.90 F g⁻¹ at 10 mV s⁻¹ (CV) and 30.74 F g⁻¹ at 0.1 A g⁻¹ (GCD).The b-value analysis suggested a combined capacitive and diffusion-controlled mechanism, while EIS results indicated a markedly reduced charge-transfer resistance (Rct = 180.8 Ω), attributed to the conductive rGO network and the porous ZIF-8 framework. These synergistic effects enhanced electron transport, ion diffusion, and redox activity. Overall, the rGO/MnO₂/ZIF-8 composite demonstrates improved electrochemical performance and structural stability, highlighting its potential as a promising electrode material for next-generation supercapacitors.