Preparation of Hierarchical Porous Activated Carbon from Banana Leaves for High‐performance Supercapacitor: Effect of Type of Electrolytes on Performance

Abstract We demonstrate a facile efficient way to fabricate activated carbon nanosheets (ACNSs) consisting of hierarchical porous carbon materials. Simply heating banana leaves with K 2 CO 3 produce ACNSs having a unique combination of macro‐, meso‐ and micropores with a high specific surface area of ∼1459 m 2 g −1 . The effects of different electrolytes on the electrochemical supercapacitor performance and stability of the ACNSs are tested using a two‐electrode system. The specific capacitance ( C sp ) values are 55, 114, and 190 F g −1 in aqueous 0.5 M sodium sulfate, organic 1 M tetraethylammonium tetrafluoroborate in acetonitrile, and pure ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]) electrolytes, respectively. The ACNSs also shows the largest potential…