Electrochemical Performance of rGO/NiCo2O4@ZnCo2O4 Ternary Composite Material and the Fabrication of an all-Solid-State Supercapacitor Device

Abstract

An rGO/NiCo₂O₄@ZnCo₂O₄ (RNZC) ternary composite material is synthesized using a simple hydrothermal method. In this report, we demonstrate the effect of rGO concentration on the electrochemical behavior of the rGO/NiCo₂O₄@ZnCo₂O₄ composite materials. The specific capacity values of the ternary composite materials increase with rGO concentration up to 50 mg. Furthermore, on increasing the rGO concentration, the capacity value decreases. Among the prepared samples, the composite with 50 mg of rGO (RNZC3) exhibits a maximum specific capacity of 1197 C g–¹ at a current density of 1 A g–¹. We also demonstrate the design of a supercapacitor device with high specific energy density using RNZC3. The RNZC3//RNZC3 symmetric supercapacitor device exhibits a maximum energy density of 62 W h kg–¹. In the case of an asymmetric supercapacitor device, the applied potential range is extended beyond the water decomposition range. Enhancement of the potential window ensures to achieve a high energy density. The RNZC3//rGO asymmetric supercapacitor device reaches the highest energy density of 71 W h kg–¹ and the corresponding power density is 0.98 kW kg–¹.