High energy density solid-state supercapacitors based on porous carbon electrodes derived from pre-treated bio-waste precursor sugarcane bagasse. (1st November 2022)

• Record Type: Journal Article
• Authors: Mohit, ; Yadav, Neetu; Hashmi, S.A.
• Is Part Of: Journal of energy storage. Volume 55:Part A(2022)
• Publication Date: 2022-11-01
• Subjects: Supercapacitor -- Gel-polymer electrolyte -- Sugarcane bagasse -- Activated carbon -- Charging/discharging -- Electrochemical analysis; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2022.105421
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: Supercapacitors with hierarchical porous carbon electrodes and ionic liquid incorporated quasi-solid-state gel polymer electrolyte are of the current area of interest as environment friendly and cost-effective power sources. Herein, we report hierarchical porous activated carbons (ACs) derived from a waste-bioresource sugarcane bagasse, prepared following hydrothermal and solvent (ethanol) soaking pre-treatments, followed by chemical/physical activations. AC-powders obtained from hydrothermal and ethanol-soaking pre-treatments show an increase in microporosity with optimum mesoporous interiors suitable to use as supercapacitor electrodes. The ACs have been electrochemically tested as supercapacitor electrodes with flexible quasi-solid-state gel polymer electrolyte comprising 0.5 M sodium triflate (NaTf) in an ionic liquid 1-ethyl-3-methylimidazolium trifluoromethane-sulfonate (EMITf) incorporated in poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) with high ionic conductivity (~8.5 mS cm −1 ) and high electrochemical stability (~4.7 V versus Ag/Ag + ). The supercapacitor based on AC-electrodes obtained after ethanol soaking pre-treatment i.e., ESB-electrodes show optimum charge-discharge performance in terms of specific capacitance (~193 F g −1 ), specific energy (~32 Wh kg −1 ) and maximum power density (~55 kW kg −1 ). The ESB-based supercapacitors also illustrate relatively high rate-performance as compared to other AC-electrodes, studied in this report. The high energy storage in the supercapacitor is evident from the glow of LED for substantial duration. The device shows stability up to ~10, 000 charge-discharge cycles with ~20 % initial fading in specific capacitance and ~100 % Coulombic efficiency. Graphical abstract: Unlabelled Image Highlights: Activated carbons (ACs) from sugarcane bagasse (SB) found suitable EDLC-electrodes. Ethanol-soaking treatment substantially improves electrochemical behaviour of AC. Solid-state EDLC with flexible gel electrolyte shows high capacitance (~193 F g −1 ). Device stores high energy (~32 Wh kg −1 ) with maximum power (~55 kW kg −1 ). The EDLC shows stable performance for 10, 000 GCD cycles with ~20 % initial fading.