Electrochemical Performance of Thespesia Populnea Seeds Derived Activated Carbon - Supercapacitor and Its Improved Specific Energy in Redox Additive Electrolytes

Supercapacitor (SC) is a promising high power energy storage device for specific applications. In the last few decades, various carbon-based materials with rational surface alterations, and carbon composites have been explored as electrodes for SCs. In addition to the redox behavior of the electrode materials, it has been proposed to use highly reversible redox species in the electrolytes, which can improve the performance of the SCs through redox processes at the electrode-electrolyte interface. Herein, the activated carbon derived from Thespesia Populnea Seeds (TPC) is explored for supercapacitor application in redox additive electrolyte. The electrochemical capacitive performance of TPC was studied using three different redox additives in 1M Na₂SO₄ electrolyte. Among the three redox additives, an outstanding specific capacity of 1779 C/g was observed in hydroquinone (HQ)/Na₂SO₄, which is superior to K₃[Fe(CN)₆]/Na₂SO₄ (1440 C/g) and FAS/Na₂SO₄ (873 C/g) electrolytes. The fabricated TPC symmetric cell in HQ/Na₂SO₄ delivered an enhanced electrochemical performance (1096 C/g at 1 A/g) and a maximum specific energy of 76 Wh/kg in HQ/Na₂SO₄.