Facile synthesis of CuAl₂O₄/rGO nanocomposite via the hydrothermal method for supercapacitor applications

Transition metal-based spinel oxides are fascinating supercapacitor electrodes materials due to their good specific capacitance (C_s) and cost-effectiveness. But the spinel materials show poor cycling stability due to their limited surface area. This issue was reduced by using carbon-based electrode materials such as rGO, which enhances the electroactive surface area that leads to improve the number of reactive sites. In this research, a simple hydrothermal approach was utilised to synthesise the CuAl₂O₄/rGO (CAO/rGO) nanocomposite. It successively characterised with different analytical techniques to study the physiochemical property of the synthesized materials. Additionally, the potential of the materials as the electrode was determined with a three-electrode configuration by utilising different electrochemical tools that were performed to assess the characteristics of the electrode material. The synthesised nanocomposite exhibits a magnificent specific capacitance (C_s) of 1206.14 F/g at 1 A/g, while demonstrating specific energy (E_d) of 34.83 Wh kg⁻¹ and specific power (P_d) of 228 W kg⁻¹ which is higher than individuals and also shows high retention capacitance value of 93.36% after 8000th charge/discharge (GCD) cycles. The symmetric behaviour of the fabricated electrode is also determined with two electrode systems exhibiting the specific energy and specific capacitance of 16.54 Wh kg⁻¹ and 601.91 F/g, correspondingly. This study demonstrates that incorporating rGO into CuAl₂O₄ nanoarray improves energy storage performance and it has the potential to work in other energy storage devices.