Symmetric Supercapacitor Electrodes from KOH Activation of Pristine, Carbonized, and Hydrothermally Treated Melia azedarach Stones

Abstract

Waste biomass-derived activated carbons (ACs) are promising materials for supercapacitor electrodes due to their abundance and low cost. In this study, we investigated the potential use of Melia azedarach (MA) stones to prepare ACs for supercapacitors. The ash content was considerably lower in MA stones (0.7% ash) than that found in other lignocellulosic wastes. ACs were prepared by KOH activation of pristine, carbonized, and hydrothermally-treated MA stones. The morphology, composition, surface area, porosity, and surface chemistry of the ACs were determined. Electrochemical measurements were carried out in three- and two-electrode cells, 3EC and 2EC, respectively, using 1 M H2SO4 as the electrolyte. The highest capacitance from galvanostatic charge-discharge (GCD) in 2EC ranged between 232 and 240 F·g−1 at 1 A·g−1. The maximum energy density reached was 27.4 Wh·kg−1 at a power density of 110 W·kg−1. Electrochemical impedance spectroscopy (EIS) revealed an increase in equivalent series resistance (ESR) and charge transfer resistance (RCT) with greater ash content. Electrochemical performance of MA stone-derived ACs was compared with that of other ACs described in the recent literature that were prepared from different biomass wastes and results showed that they are among the best ACs for supercapacitor applications.

Biomass-Derived Porous Carbon Materials for Supercapacitor

“…Compared with conventional KOH activation, impregnate-activation method resulted in PC derived from pine tree sawdust with higher surface area and richer interconnected pores, and achieved good C s in the organic electrolyte (146 F/g) and IL electrolyte (224 F/g) (Wang et al, 2017). Except for these woody materials aforementioned, other woody wastes, such as spruce bark (Sun et al, 2018), Java Kapok tree (Kumar et al, 2018), plane tree (Yao et al, 2017), Melia azedarach (Morenocastilla et al, 2017), auriculiformis tree bark (Momodu et al, 2017), ginkgo leaves (Hao et al, 2017) (Figure 8) were developed as carbon for fabricating PC, whose C s was all better than commercial activated carbon. Musa basjoo, which appears like a tree and have three layers of structure involves nano-/micro-/millimeter level, that endowed the PC with abundant interconnected pores after KOH activation.…”

Carbon Microspheres with Tailored Texture and Surface Chemistry As Electrode Materials for Supercapacitors

“…The electrochemical performance was studied in a voltage window of 0–0.9 V. Cyclic voltammetry (CV) was carried out at several scan rates ranging from 0.5 to 30 mV s –1 ), and a charge and discharge galvanostatic (GD) study ranged from 0.125 to 7 A g –1 of current densities. The gravimetric capacitance was calculated from CV, C CV , and GD, C GD , as described elsewhere. ,− Impedance spectroscopy measurements were determined from 1 mHz to 100 kHz with AC amplitude of 10 mv. The electrical energies, E (Wh kg 1– ) and power densities, P (W kg 1– ), were calculated as described elsewhere. , Cycling/aging tests were carried out at 1 A g –1 over 12000 charge–discharge cycles.…”

“…The gravimetric capacitance was calculated from CV, C CV , and GD, C GD , as described elsewhere. ,− Impedance spectroscopy measurements were determined from 1 mHz to 100 kHz with AC amplitude of 10 mv. The electrical energies, E (Wh kg 1– ) and power densities, P (W kg 1– ), were calculated as described elsewhere. , Cycling/aging tests were carried out at 1 A g –1 over 12000 charge–discharge cycles. More details were included in the Supporting Information.…”

“…The electrical energies, E (Wh kg 1− ) and power densities, P (W kg 1− ), were calculated as described elsewhere. 42,45 Cycling/aging tests were carried out at 1 A g −1 over 12000 charge−discharge cycles. More details were included in the Supporting Information.…”

Influence of Surface Chemistry on the Electrochemical Performance of Biomass-Derived Carbon Electrodes for its Use as Supercapacitors

“…Carbon based materials are probably the best candidates for this type of electrochemical applications taking in account the extended literature published during the last years [4,5,6]. On the other hand, a different type of precursors are used for the preparation of activated carbon from waste agriculture products such as olive stone [7,8,9], melia azedarach stones [10], argan seed shells [11], coconut [12,13], etc., by using different methods of chemical and physical activation [14,15]. The use of biomass wastes for carbon electrodes preparation and its use as supercapacitors is one of the best available options, not only for their very high electro-chemical performance but also for the economy of the synthesis process [3].…”