Activated Carbon From Rice Bran Oil as Cost Effective Electrode Material for Supercapacitors

Materials development for energy generation and storage has been widely investigated in the present decade. In this work, carbon collected from rice bran oil burning, termed nanocarbon (NC) and its activated form (ANC), is well characterized for structure, morphology, and electrochemical properties, to assess their potential use in supercapacitor applications. The performance of the supercapacitors, fabricated using NC, ANC, and a commercial carbon (CC) as electrode material, has been evaluated on FTO-coated glass plates. The device performance has been tested in three different electrolytes, namely, 6 M KOH, 1 M H₂SO₄, and 0.5 M solution of 1-Butyl-3-methylimidazolium hexafluorophosphate in acetonitrile. The supercapacitor with ANC electrode in 6 M KOH electrolyte yielded a specific capacitance of 97.77 F g⁻¹ at 1 A g⁻¹ current density and retained 93% efficiency after 5000 cycles, quite comparable to the commercial carbon-based device. The device also showed a higher energy density of 11 Wh kg⁻¹ and power density of 900 W kg⁻¹. While using the ionic liquid electrolyte, the specific capacitance was lowered to 40.44 F g⁻¹ at 1 A g⁻¹ current density, but with a wider potential window of 2.5 V. The results confirm that carbon soot from rice bran oil burning, which is a waste form of carbon, on activation by simple air annealing could be a potentially promising electrode material for supercapacitor applications.