Porous Architecture of Ni substituted ZnMn2O4 nanospheres as an electrode material for supercapacitor applications

To explore the electrochemical performance, we synthesized a series of Ni-substituted ZnMn2O4 using sol‒gel auto-combustion route. The formation of the tetragonal phase for ZnMn2O4 and its transformation into a cubic phase upon Ni substitution is confirmed by the X-ray diffraction technique. Morphology analysis revealed that average particle size is increased from 150 to 250 nm when contents of Ni are increased from x = 0.0 to x = 1.0, respectively. Employing cyclic voltammetry and galvanostatic charge and discharge test, it is observed that pure ZnMn2O4 has a specific discharge capacity of 11.2 F/g which decreased to 8.49 F/g for ZnMn2O4. The tuning of this electrochemical performance is accredited to its hierarchical structure which facilitates charge transfer, large reaction surface area, and good structure stability. All these results validate that Zn1-xNixMn2O4 composites are a suitable candidate as electrode material in supercapacitors.