Graphene-metal oxide composites have been recently introduced as promising materials for energy storage and heterogeneous catalysis. The synergy between graphene and metal oxide enhances the performance of these composite materials in comparison to their individual components.¹ Improved electrochemical properties such as high capacity and cycling stability makes graphene-NiCo₂O₄ composite a promising supercapacitor electrode.² In this work, we assemble the composite electrode by electrophoresis on graphite electrode. We firstly disperse graphene sheets in the electrolyte solution by electrochemical exfoliation³ of the graphite electrode. NiCo₂O₄ platelets, separately prepared from Ni and Co salts by chemical synthesis route⁴, were then added into the electrolyte solution to form graphene sheet-NiCo₂O₄ platelet mixture suspension. Finally, graphene sheets and NiCo₂O₄ platelets are assembled on the exfoliated surface of the original graphite electrode in one electrophoretic deposition step. Deposition parameter-composite microstructure relationship was studied in detail. Controlled parameters include nominal input mass ratio of the two components, magnitude of the electrical field, and electrolyte solution composition. The final composite electrode were characterized using cyclic voltammetry and electrochemical impedance spectroscopy to estimate its functionality for supercapacitor application.

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