Activated carbon fibres as high performance supercapacitor electrodes with commercial level mass loading

Abstract

Turning waste cotton into useful energy storage device shows great scientific and industrial importance due to the sustainability, abundance, low-cost and environmental friendliness. This study delineates the fabrication and electrochemical performances of activated porous carbon fibres used as high performance supercapacitor electrodes with commercial level mass loading (150 ± 10 μm thickness, 10 ± 1 mgcm−2). The fabricated supercapacitor electrodes showed combination of high gravimetric and volumetric capacitances in three different electrolytes 6 M KOH (0–1 V), 0.5 M Na2SO4 (0–1.8 V) and 1 M TEABF4/AN (0–2.7 V) due to the thick electrodes (high active mass loading). Particularly, the electrodes in organic electrolyte TEABF4 at 2.7 V exhibited excellent gravimetric and volumetric capacitances of 112 Fg-1 and 74 Fcm−3 at 1 Ag-1, respectively with long life cycle (87% capacitance retention after 10,000 cycles). Hence, it delivers maximum gravimetric and volumetric energy density of 29.50 Whkg−1 and 19.42 WhL−1, respectively. A practical approach to combine the supercapacitor (4 coin cells in series, 2.7 V x 4) with commercial solar lantern to integrate self-sustaining power pack is demonstrated. It is evidently proved that activated carbon fibres with high areal capacitance delivered high volumetric energy to the device which is prime requisite for practical implementation.