Modified Activation Process for Supercapacitor Electrode Materials from African Maize Cob

Abstract

In this work, African maize cobs (AMC) were used as a rich biomass precursor to synthesize carbon material through a chemical activation process for application in electrochemical energy storage devices. The carbonization and activation were carried out with concentrated Sulphuric acid at three different temperatures of 600, 700 and 800 °C, respectively. The activated carbon exhibited excellent microporous and mesoporous structure with a specific surface area that ranges between 30 and 254 m2·g−1 as measured by BET analysis. The morphology and structure of the produced materials are analyzed through Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Boehm titration, X-ray Photoelectron Spectroscopy (XPS) and Raman Spectroscopy. X-ray photoelectron spectroscopy indicates that a considerable amount of oxygen is present in the materials. The functional groups in the activated carbon enhanced the electrochemical performance and improved the material’s double-layer capacitance. The carbonized composite activated at 700 °C exhibited excellent capacitance of 456 F g−1 at a specific current of 0.25 A g−1 in 6 M KOH electrolyte and showed excellent stability after 10,000 cycles. Besides being a low cost, the produced materials offer good stability and electrochemical properties, making them suitable for supercapacitor applications.

Sustainable Materials from Fish Industry Waste for Electrochemical Energy Systems

“…The power and energy-storage capabilities of carbon-based EDLCs are attributed to the physical and chemical properties of the carbon electrodes and there has been great attention paid to active material development with increased surface area [46]. Preferred materials include graphene, carbon aerogel, carbon nanotubes and their composites; however, these are scarce, expensive and tend to agglomerate during synthesis [125].…”

“…Instrumental and methodological details regarding different synthetic strategies for biomass-derived carbon can be found in [40][41][42]. Due to a better electrolyte seepage and higher charge storage capabilities compared to conventional materials, porous and high-surface carbon materials are suitable as electrode materials for batteries and supercapacitors [43][44][45][46][47]. As a result, the research on preparation techniques and activator typologies has led to the concept of engineered biochar, wherein the physicochemical properties, performance and environmental benefits of pristine biochar can be tailored for specific applications [35,48].…”

Phyllanthus emblica Seed-Derived Hierarchically Porous Carbon Materials for High-Performance Supercapacitor Applications

“…Owing to the exceptionally high specific-surface-area, large porosity, well-defined pore-size distributions, interconnected mesopores, high electrical-conductivity and electrochemical stability, hierarchically micro- and mesopore architectures, and low cost, the nanoporous activated-carbons have received much interest as the efficient electrode in the high-performance supercapacitor, which is a leading electrochemical-energy-storage system [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. In supercapacitors, also known as electrical double-layer capacitors (EDLCs), charges are stored by means of electrical double-layers at the surface of electrode material governed by the electrolyte-ion diffusion from the electrolyte solution to the electrode surface.…”

“…The following supporting information can be downloaded at: , Figure S1: FTIR spectra of the carbonized samples; Figure S2: supplementary SEM image of AmP-900; Figure S3: extra SEM image of AmC-K700; Figure S4: supplementary SEM image of AmC-K800; Figure S5: supplementary SEM image of AmC-K900; Figure S6: supplementary SEM image of AmC-K1000; Figure S7: GCD curves of AmC_K700; Figure S8: Capacitance retention performance of AmC_K700, AmC_K800, AmC_K900, and AmC_K1000; Table S1: Comparison of the specific capacitance of Amala seed carbon with more activated carbons prepared from other biomasses [ 1 , 3 , 4 , 5 , 41 , 43 , 47 , 51 , 53 , 65 , 69 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 ].…”

Flax-Derived Carbon: A Highly Durable Electrode Material for Electrochemical Double-Layer Supercapacitors

“…Commercially available EDLC capacitors deploy ACs because they meet the abovementioned requirements [ 13 ]. Biomass-derived carbons represent an interesting source of ACs since they are abundant and naturally renewable [ 14 ]. These bio-derived ACs include, for instance, wood sawdust [ 15 ], coffee endocarp [ 16 ], rotten tomatoes [ 17 ], rice straw [ 18 ], winery wastes [ 19 ], or sunflower seed shell [ 20 ].…”