Orange-Peel-Derived Carbon: Designing Sustainable and High-Performance Supercapacitor Electrodes

Abstract

Abstract:Interconnected hollow-structured carbon was successfully prepared from a readily available bio-waste precursor (orange peel) by pyrolysis and chemical activation (using KOH), and demonstrated its potential as a high-performing electrode material for energy storage. The surface area and pore size of carbon were controlled by varying the precursor carbon to KOH mass ratio. The specific surface area significantly increased with the increasing amount of KOH, reaching a specific surface area of 2521 m 2 /g for a 1:3 mass ratio of precursor carbon/KOH. However, a 1:1 mass ratio of precursor carbon/KOH displayed the optimum charge storage capacitance of 407 F/g, owing to the ideal combination of micro-and mesopores and a higher degree of graphitization. The capacitive performance varied with the electrolyte employed. The orange-peel-derived electrode in KOH electrolyte displayed the maximum capacitance and optimum rate capability. The orange-peel-derived electrode maintained above 100% capacitance retention during 5000 cyclic tests and identical charge storage over different bending status. The fabricated supercapacitor device delivered high energy density (100.4 µWh/cm 2 ) and power density (6.87 mW/cm 2 ), along with improved performance at elevated temperatures. Our study demonstrates that bio-waste can be easily converted into a high-performance and efficient energy storage device by employing a carefully architected electrode-electrolyte system.

Waste Coffee Management: Deriving High-Performance Supercapacitors using Nitrogen-Doped Coffee-Derived Carbon

“…Furthermore, during the chemical activation process, the conductivity of carbon can be greatly influenced due to induced porosity and may result in inferior charge storage performance. This can be observed by a reduced graphitic phase of carbon with increasing chemical activation, as reported by previous studies [10,[20][21][22]. However, the conductivity of carbon-based materials can be improved by doping with elements such as nitrogen and phosphorus, which can significantly improve the density of states for carbon [23].…”

“…Upon activation with KOH, a significant increase in porosity and surface area was observed. As the coffee carbon reacts with KOH, the reaction proceeds as following [11]: The chemically-activating agent KOH reacts with carbon to form potassium carbonate, which can be easily decomposed and washed away using 1 M HCl to obtain a highly porous carbon structure [12,20]. Such carbon is a type I isotherm, where a significant amount of nitrogen adsorption occurred at relatively low pressure followed by almost constant nitrogen adsorption at high pressures.…”

Supercapacitor Electrodes from Viscose-Based Activated Carbon Fibers: Significant Yield and Performance Improvement Using Diammonium Hydrogen Phosphate as Impregnating Agent

“…The use of DAHP as an impregnation agent before carbonization did not affect the spectra. Overall, the graphitization level of the ACFs with I D /I G = 1.23 is significantly higher than that of commercially available activated carbons, which show an I D /I G value as high as 1.92 [25]. To investigate the structure of the carbonized and activated fibers, Raman spectra ( Figure 2) were recorded.…”

Biomass‐Derived Carbon: A Value‐Added Journey Towards Constructing High‐Energy Supercapacitors in an Asymmetric Fashion

“…It is the oldest source of energy after the sun. [112] Different biomassp recursors have been selected based on these different criteria;r ice straw, [113] wheat straw, [114] popularc atkins, [115] and pistachio [116] have been selected due to their low cost and ease of availability.I na ddition, chickene ggshells [117] ando range peel [118] are examples of precursors that were considered based on their unique hierarchicalp orous microstructures. Energyf rom sunlight is stored as chemical energy in biomass and this energy can be widely used to meet our increasing energy needs, such as heating, cooking, and transport fuel.…”

“…Selection of asuitable BDC precursor depends on its cost, intrinsic microstructure, and elemental composition. [112] Different biomassp recursors have been selected based on these different criteria;r ice straw, [113] wheat straw, [114] popularc atkins, [115] and pistachio [116] have been selected due to their low cost and ease of availability.I na ddition, chickene ggshells [117] ando range peel [118] are examples of precursors that were considered based on their unique hierarchicalp orous microstructures. At the same time, Bacillus subtilis, [90] human hair, [119] and chitin [120] have been selected based on the abundant presenceo fn itrogen, oxygen,a nd sulfur atoms in their structures.…”