Preparation of Hierarchical Porous Activated Carbon from Banana Leaves for High‐performance Supercapacitor: Effect of Type of Electrolytes on Performance
Chanchal Kumar Roy, Syed Shaheen Shah, Akter Hossain Reaz, Sharmin Sultana, Al‐Nakib Chowdhury, Shakhawat H. Firoz, Md. Hasan Zahir, Mohammed Ameen Ahmed Qasem, Md. Abdul Aziz
Abstract
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 window of 3.0 V, the highest specific energy (59 Wh kg −1 ) and specific power (750 W kg −1 ) in [BMIM][PF 6 ]. A mini‐prototype device is prepared to demonstrate the practicality of the ACNSs.