KOH‐Activated Porous Carbons Derived from Chestnut Shell with Superior Capacitive Performance

Abstract

Porous carbons (PC) were prepared from a waste biomass named chestnut shell via a two-step method involving carbonization and KOH activation. The morphology, pore structure and surface chemical properties were investigated by scanning electron microscopy (SEM), N 2 sorption, Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The carbons have been evaluated as the electrode materials for supercapacitors by a two-electrode system in 6 mol/L KOH electrolyte. Benefiting from the porous texture, high surface area and high oxygen content, the PCs derived from chestnut shell have exhibited high specific capacitance of 198.2 (PC-1), 217.2 (PC-2) and 238.2 F•g 1 (PC-3) at a current density of 0.1 A•g 1 , good rate capability of 55.7%, 56.6% and 54.9% in a range of 0.1-20 A•g 1 and high energy density of 5.6, 6.1 and 6.7 Wh•kg 1 , respectively. This is believed to be due to electric double layer capacitance induced by the abundant micropores and extra pseudo-capacitance generated by oxygen-containing groups. At a power density of 9000 Wh•kg 1 , the energy density is 3.1, 3.5 and 3.7 Wh•kg 1 for PC-1, PC-2 and PC-3, respectively, demonstrating the potential of the carbons derived from chestnut shells in energy storage devices.

Chestnut-Derived Activated Carbon as a Prospective Material for Energy Storage

“…Our electrodes were in the form of pellets with mass loading of approximately 10 mg cm −2 , which is high compared to other works [ 31 , 33 , 34 , 35 , 55 , 56 ]. In many papers, the electrodes are deposited on nickel foam with very low mass loading of 1.5–5 mg cm −2 [ 31 , 33 , 34 , 35 , 55 , 56 ], which improves charge propagation and diffusion of the electrolyte through the electrode. Besides, Ni foam as a current collector in the strong alkaline medium may contribute to the capacitance values due to the oxidation of nickel to Ni(OH) 2 and NiOOH [ 57 , 58 , 59 ].…”

“…Moreover, there are mistakes in literature reports regarding calculation of capacitance of the cell. The authors sometimes recalculate the values per mass of single electrode instead of mass of both electrodes, which make the reported C , E and P values significantly overestimated (e.g., [ 35 , 56 ]).…”

N-Doped Mesoporous Carbon Sheets/Hollow Carbon Spheres Composite for Supercapacitors

“…Moreover, it could be seen that N-MCS/HCS-0.15 had high capacitance retentions of >68.5% (Figure c) for current densities of 0.5 to 10 A g –1 . The energy density and power density of N-MCS/HCS-0.15 calculated from GCD discharging curves are shown in Figure d and compared with those of other carbon materials. − The Ragone plot reveals that the maximum energy density of N-MCS/HCS-0.15 is 15.1 W h kg –1 at a specific power density of 0.78 kW kg –1 and maintains 10.4 W h kg –1 at a high specific power density of 14.9 kW kg –1 . It is obvious that the energy density of N-MCS/HCS-0.15 is higher than that of other reported carbon materials.…”

Preparation and Characterization of Porous Carbon from Mixed Leaves for High‐Performance Supercapacitors

“…[ 16 ] Hence, more and more attention has been paid to natural biomass, which are renewable, and environmentally friendly. [ 17‐19 ] So far porous ACs have been prepared using such as soybean root, [ 20 ] corn stalk, [ 21 ] cotton stalk, [ 22 ] platanus leaves, [ 23 ] tea leaves, [ 24 ] palm flower, [ 25 ] elm flower, [ 26 ] banana peel, [ 27 ] orange peel, [ 28 ] sun flower seed shell, [ 29 ] camellia oleifera, [ 30 ] rice husk, [ 31 ] etc . Among various plants‐derived ACs, carbon from leaves exhibit attractive performance for energy storage.…”