Effect of different synthesis methods on morphology and electrochemical behavior of spinel NiCo2O4 nanostructures as electrode material for energy storage application

In the present study, four different methods viz. Hydrothermal, Sol-Gel, Solid-state, Co-precipitation methods are used to successfully synthesize the nickel cobaltite (NiCo2O4) nanostructures. The product obtained from the hydrothermal method shows an intermediate behavior between battery-type and pseudocapacitor-type, whereas other methods yield pure battery-type NiCo2O4 nanostructures. Scanning electron microscopy (SEM) examination evaluated the distinct morphology acquired from each methodology, which had a massive effect on the electrochemical performance of the materials as formulated. To assess the electrochemical performance in 2 M KOH electrolyte, techniques such as Galvanostatic charge–discharge (GCD) and cyclic voltammetry (CV) have been used. The greatest specific capacity recorded in the case of sol–gel synthesized product was 617.22C/g at a current density of 1.0 A/g, but significantly enhanced rate-performance is observed in the case of Co-precipitation produced product (568.20C/g at 1.0 A/g and 374.26C/g at 10.0 A/g). The obtained results verified the effect of different methods of synthesis on morphology and electrochemical performance of the same electrode material prepared under identical environmental conditions.