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Sustainable conversion of biomass waste into an economic and high performance electrical energy storage device receives excellent scientific and technological interest. The high manufacturing cost and low energy density are the major obstacles for supercapacitor developers. To overcome these obstacles, the present study delineates the fabrication of higher energy density, faster charging, and excellent durable supercapacitor electrodes derived from industrial waste cotton used as a sustainable and economic carbon resource. The obtained supercapacitor electrode exhibits excellent volumetric capacitance of 87 F cm–3 at 1 A g–1, and it delivers higher volumetric energy density of 30.94 W h L–1 owing to the simultaneous achievement of high loading of active mass (9 mg cm–2) and maximum voltage window of 3.2 V. Besides, the supercapacitor electrodes showed an excellent durability up to 15000 charge–discharge cycles at 4 A g–1 even at higher voltage of 3.2 V. It can be ascribed that a large electrolyte ion accessible surface area (1893 m2 g–1) with an interconnected porous network of activated carbon fibers can enhance the rapid electrolyte ion transport even at high current load. Very interestingly, good capacitance retention at high current with high voltage clearly demonstrates the presence of the optimum pore size of the carbon electrode which can match with the electrolyte ion size for rapid capacitive response. Furthermore, integration of a solar powered supercapacitor as a self-powering energy harvest and energy storage device is designed, and it powers the commercial solar lantern. This work provides a simple and feasible synthetic strategy of converting sustainable biomass waste into economic and high performance supercapacitor electrodes for real-time supercapacitor applications.
Vijayakumar et al. (Wed,) studied this question.