Highly Porous Heteroatom Doped-Carbon Derived from Orange Peel as Electrode Materials for High-Performance Supercapacitors

Abstract

Biomass conversion to heteroatom-doped carbon materials is considered to be an effective and inexpensive method for energy conversion. Orange peel is rich in the elements carbon, nitrogen and oxygen. Herein, nitrogen and oxygen co-doped carbon is prepared by high-temperature carbonization and activation of orange peels. Two activating agents, KOH and K2FeO4, are adopted in the preparation. The OC-1-K sample derived from orange peel activated by KOH has a large specific surface area of 917.66 cm 2 g -1 . When used as a supecapacitor electrode material, the OC-1-K sample displays a high specific capacitance of 282.3 F g -1 at 1 A g -1 . Even when the current density increases to 20 A g -1 , the discharge capacity is 212 F g -1 , indicating good rate performance. After 4000 chargedischarge cycles in 2 mol L -1 KOH electrolyte, the capacitance is maintained at 209.8 F g -1 at 20 A g -1 , achieving good cycling stability. All these results are superior to those of the OC-1-G sample obtained by K2FeO4 activation. These results indicate that KOH is more effective in activating orange peels. The excellent electrochemical performance of the OC-1-K sample suggests good application prospects in supercapacitors.

Identified potential of mangosteen peel agricultural waste as electrodes component of a supercapacitor: a study of electrochemical behaviour

“…This diminutive internal resistance drop is attributed to the presence of self-doping heteroatoms, aligning with the findings from the CV analysis [30]. Furthermore, at higher current densities, a quasi-linear isosceles triangle curve emerges, further substantiating the graphitization and enhanced conductivity features [30,40]. With the progressive escalation of current density, there is a marked increase in the rate of decrease of internal resistance, a consequence of accelerated ion movement within the electrolyte over a truncated timeframe, rendering it challenging for ions to effectively infiltrate the pores of the SMPP-0.3-ZC carbon electrode [27,42,43].…”

“…These GCD profiles depict nearly symmetrical isosceles triangles characterized by minimal distortion, indicative of favorable electrical double-layer capacitive (EDLC) properties, corroborating the observed low internal resistance drop [18,41]. This diminutive internal resistance drop is attributed to the presence of self-doping heteroatoms, aligning with the findings from the CV analysis [30]. Furthermore, at higher current densities, a quasi-linear isosceles triangle curve emerges, further substantiating the graphitization and enhanced conductivity features [30,40].…”

“…This manifestation signifies the hallmark electrochemical doublelayer capacitance (EDLC) properties, indicative of reversible ion diffusion processes. The limited distortion of the rectangular profile is attributed to the concurrent pseudo-capacitance originating from the self-doping of heteroatoms, specifically carbon (C) and oxygen (O), within the biomass-derived carbon framework [30,33,34]. Remarkably, even at an accelerated scanning rate of 10 mV s -1 , the CV curve of the SMPP-0.3-ZC carbon remarkably sustains its nearly rectangular shape, albeit with increased distortion.…”

“…These nanofiber structures collectively culminate in the creation of an intricate three-dimensional porous microarchitecture, thereby engendering the formation of an assorted array of pores. The presence of these nanofiber sheets serves as an ideal conduit for the unhindered penetration of electrolytes, thereby substantially augmenting the capacitance performance of the carbon electrodes [29][30][31][32]. The elemental composition of the SMPP-0.3-ZC carbon specimen was meticulously probed through the utilization of EDX mapping analysis.…”

Research on High-Value Utilization of Carbon Derived from Tobacco Waste in Supercapacitors

“…According to the EIS results, the bulk solution resistance (Rs) and charge transfer resistance (Rct) of TC-1//TC-1 were 0.588 Ω and 0.101 Ω, respectively, which ensured fast charge transfer and ion diffusion. The near-perpendicular line in the low-frequency region conformed to the ideal electric double-layer carbon materials characteristics ( Figure 7 d) [ 47 ]. The Ragone plot of the TC-1//TC-1 symmetrical supercapacitor is shown in Figure 7 e. At current densities of 0.5 A g −1 , the power density was 300 W kg −1 , and the energy density reached 10.4 Wh kg −1 , while at current densities of 10 A g −1 , the power density was 6000 W kg −1 , and the energy density was 7.3 Wh kg −1 .…”