Nelumbo nucifera Seed–Derived Nitrogen-Doped Hierarchically Porous Carbons as Electrode Materials for High-Performance Supercapacitors

Abstract

Biomass-derived activated carbon materials with hierarchically nanoporous structures containing nitrogen functionalities show excellent electrochemical performances and are explored extensively in energy storage and conversion applications. Here, we report the electrochemical supercapacitance performances of the nitrogen-doped activated carbon materials with an ultrahigh surface area prepared by the potassium hydroxide (KOH) activation of the Nelumbo nucifera (Lotus) seed in an aqueous electrolyte solution (1 M sulfuric acid: H2SO4) in a three-electrode cell. The specific surface areas and pore volumes of Lotus-seed–derived carbon materials carbonized at a different temperatures, from 600 to 1000 °C, are found in the range of 1059.6 to 2489.6 m2 g−1 and 0.819 to 2.384 cm3 g−1, respectively. The carbons are amorphous materials with a partial graphitic structure with a maximum of 3.28 atom% nitrogen content and possess hierarchically micro- and mesoporous structures. The supercapacitor electrode prepared from the best sample showed excellent electrical double-layer capacitor performance, and the electrode achieved a high specific capacitance of ca. 379.2 F g−1 at 1 A g−1 current density. Additionally, the electrode shows a high rate performance, sustaining 65.9% capacitance retention at a high current density of 50 A g−1, followed by an extraordinary long cycle life without any capacitance loss after 10,000 subsequent charging/discharging cycles. The electrochemical results demonstrate that Nelumbo nucifera seed–derived hierarchically porous carbon with nitrogen functionality would have a significant probability as an electrical double-layer capacitor electrode material for the high-performance supercapacitor applications.

Porous activated carbon materials from Triphala seed stones for high-performance supercapacitor applications

“…Figure 6a shows the GCD profiles of all the samples at 1 A g −1 , including the reference carbon, which are of triangular form confirming an EDLC-type charge storage mechanism. From the above result, we see that the reference sample MxP-500 shows the lowest charge discharge time whereas the MxC-Z700 shows the highest charge discharge time which confirms the maximum charge storage capacity because of the nanoporous structure [30][31][32]. The GCD curves of all the samples have the triangular form and remains even at high current density of 50 A g −1 ), that confirm the effective ion diffusion mechanism at interiors of the nanoporous carbon materials at higher current densities.…”

Ultrahigh Surface Area Hierarchically Porous Carbon Materials from Polyacrylamide–Cellulose Hydrogel for High-Performance Supercapacitors

“…BET surface area is ca. 92.4 m 2 g –1 . , The introduction of the activator K 2 CO 3 plays a significant role in developing the porosity of carbon materials. During the carbonization process, K 2 CO 3 reacts with the carbon precursor (in this case, PAM–HPC), forming volatile gases (e.g., CO 2 , H 2 O), which exit the carbon framework. , These released gases cause the formation of pores within the carbon skeleton, resulting in large specific surface area and high nitrogen uptake.…”

Biomass Nanoarchitectonics for Supercapacitor Applications

“…In a recent report, we have found that KOH activation of Nelumbo nucifera (Lotus) seed results in self-nitrogendoped porous carbon materials with an ultrahigh surface area (2489.6 m 2 /g) 197) . The preparation method included the mixing of Lotus seed biochar with KOH pellet (1:1 wt.…”