Graphene‐Based Supercapacitor Using Microemulsion Electrolyte

Abstract Graphene‐like material prepared by a facile combustion synthesis was investigated as an electrode material in a microemulsion electrolyte. Notably, a stable voltage window of 2.2–2.4 V was achieved, surpassing previous reports for aqueous‐based electrolytes on similar materials. The fabricated supercapacitor device exhibited a commendable specific capacitance values of 59 F g −1 at 0.1 A g −1 and 32 F g −1 at 5 A g −1 , indicating its potential for high‐current applications. Mechanistic examination revealed that the charge storage primarily relies on electric double‐layer formation, with minor non‐capacitive contribution from electrode surface functionalities and the supporting electrolyte. Further analysis showed significant capacitive contributions of 85 % at 2.2 V and 67 % at 2.4 V, underscoring the dominance of the capacitive process. The fabricated supercapacitor's stability indicated a decrease as the non‐capacitive process intensified, suggesting that electrode surface functionalities predominantly contribute to cell deterioration at elevated potentials. These results highlight the potential efficacy of microemulsion electrolytes in energy storage applications.