Solvothermal Synthesis of Sr₂FeCoO₆/rGO Nanocomposite and its Energy Storage Application with Activated Charcoal in an Asymmetric Supercapacitor

The demand for portable electronics drives interest in electrode materials with fast power response, making supercapacitors as a key focus for their rapid energy delivery. The present research highlights the investigation and significance of solvothermally synthesized KOH-assisted Sr₂FeCoO₆ reduced graphene oxide (Sr₂FeCoO₆/rGO) nanocomposite. X-ray photoelectron spectroscopy reveals that Sr₂FeCoO₆ contains Co²⁺, Co³⁺, and Fe²⁺, Fe³⁺ at the surface, which assist in charge storage via reversible redox reactions. Its electrochemical investigation demonstrates specific capacitance and retention characteristics, contributing to the understanding of its potential as an efficient and economical energy storage solution. The Sr₂FeCoO₆/rGO nanocomposite with redox-additive-assisted electrolyte exhibits a specific capacitance of 577 F g⁻¹ (at 1 A g⁻¹) and capacitive retention of 77% over 5000 charge/discharge cycles. In an asymmetric cell, the energy storage performance of a hybrid nanocomposite electrode combined with an activated charcoal electrode has also been investigated as a cost-effective alternative for future energy storage applications. It achieves a specific capacitance of 272 F g⁻¹ (at 1 A g⁻¹) and capacitive retention of 72% over 5000 charge/discharge cycles. Applying Dunn's method, the intricate charge storage behavior and its contribution have been evaluated.