Fabrication and characterization of energy storing supercapacitor devices using coconut shell based activated charcoal electrode

•CST with specific surface area of 1640 m2 g−1 was synthesized using impregnation method.•XRD studies of CST confirm the formation of graphite and amorphous C.•EDLC cell has been successfully fabricated using CST as an electrode material having good energy and power density.

In the present studies coconut shell based treated activated charcoal (CST) was synthesized by chemical activation method using KOH (potassium hydroxide) as an activating agent. Surface area analysis shows that CST has mesopores of size 3 nm having specific surface area of 1640 m2 g−1. Electrochemical double layer capacitor (EDLC) was fabricated using CST as an electrode material with blend polymer electrolyte having specific capacitance of 534 mF cm−2 (equivalent to single electrode specific capacitance of 356.2 F g−1). The corresponding energy and power density of 88.8 Wh kg−1 and 1.63 kW kg−1, respectively, were achieved for EDLC.