Synthesis and electrochemical properties of CuCo2O4@Co3O4 nanocomposite for supercapacitor application

Transition metal oxide–based pseudocapacitors with various valence states are of particular interest in the field of energy storage due to their increased specific capacitance values. In particular, Copper cobaltite nanomaterials have attracted more research focus due to their multiple oxidation states in comparison to other transition metals. Spinel structures of metal oxides are of tremendous interest for energy storage applications. Mixed valence metal cations in spinel cobaltites (MCo 2 O 4 ) offer more electronic conductivity and electrochemical activity than single–component oxides. Natural abundance, good electrical and thermal stability, environment–friendly nature, and low cost motivates researchers for carrying out an extensive study of such materials. In this study, binary composite CuCo 2 O 4 @Co 3 O 4 was synthesized by facile hydrothermal method. FT–IR, XRD, FEG–SEM and XPS studies have established the successful formation of all the nanocomposites were used to primarily characterize the sample. XRD showed the existence of all the synthesized materials in crystalline form. Cyclic voltammetry (CV), Galvanostatic Charge–Discharge (GCD) and Electrochemical Impedance (EIS) measurements were recorded to examine the electrochemical characteristics. The comparative specific capacitance of the synthesized CuCo 2 O 4 @Co 3 O 4 nanocomposite displayed 542.77 Fg −1 using Glassy Carbon (GCE) as the working electrode whereas it exhibited 683.72 Fg −1 at the same current density of 1 Ag −1 using Nickel foam as the electrode substrate. The composite electrode exhibited an excellent pseudocapacitive behaviour using 1 M Na 2 SO 4 and 1 M KOH as electrolytes respectively for electrochemical measurements. Impedance analysis reveals capacitive nature of the synthesized materials. Furthermore, cyclic stability for CuCo 2 O 4 @Co 3 O 4 nanocomposite was found to be 76% (GCE) upto 1000 cycles at 5 Ag −1 and 78% (Nickel foam) upto 3000 cycles at 5 Ag −1 . Based on the study of the electrochemical performance, the synthesized transition metal oxide nanocomposite holds potency as an efficient electrode material for energy storage applications. Graphical abstract