Aromatic biomass (torch ginger) leaf-derived three-dimensional honeycomb-like carbon to enhance gravimetric supercapacitor

BACKGROUND

Porous carbon electrode (PCE) is identified as a highly suitable electrode material for commercial application due to its production process, which is characterized by simplicity, cost-effectiveness and environmental friendliness. PCE was synthesized using torch ginger (Etlingera elatior (Jack) R.M. Smith) leaves as the base material. The leaves were treated with different concentrations of ZnCl2 , resulting in a supercapacitor cell electrode with unique honeycomb-like three-dimensional (3D) morphological pore structure. This PCE comprises nanofibers from lignin content and volatile compounds from aromatic biomass waste.

RESULTS

From the characterization of physical properties, PCE-0.3 had an impressive amorphous porosity, wettability and 3D honeycomb-like structural morphology with a pore framework consisting of micropores and mesopores. According to the structural advantages of 3D hierarchical pores such as interconnected honeycombs, PCE-0.3 as supercapacitor electrode had a high specific capacitance of up to 285.89 F g-1 at 1 A. Furthermore, the supercapacitor exhibited high energy and power density of 21.54 Wh kg-1 and 161.13 W kg-1 , respectively, with a low internal resistance of 0.059 Ω.

CONCLUSION

The results indicated that 3D porous carbon materials such as interconnected honeycombs derived from the aromatic biomass of torch ginger leaves have significant potential for the development of sustainable energy storage devices. © 2023 Society of Chemical Industry.

Novel Moringa oleifera Leaves 3D Porous Carbon-Based Electrode Material as a High-Performance EDLC Supercapacitor

Biomass-based activated carbon has great potential in the use of its versatile 3D porous structures as an excellent electrode material in presenting high conductivity, large porosity, and outstanding stability for electrochemical energy storage devices. In this study, the electrode material develops through a novel consolidated carbon disc binder-free design, which was derived from Moringa oleifera leaves (MOLs) for electrochemical double-layer capacitor applications. The carbon discs are prepared in a series of treatments of precarbonized, chemical impregnation of zinc chloride, integrated pyrolysis of N₂ carbonization, and CO₂ physical activation. The physical activation temperatures applied at 650, 750, and 850 °C optimize the precursor potential. By optimizing the 3D hierarchical pore properties of the MOL750, the carbon disc binder-free design demonstrates optimal symmetric supercapacitor performance with a high specific capacitance of 307 F g^-1 at a current density of 1 A g^-1 in an aqueous electrolyte solution of 1 M H₂SO₄. Furthermore, the extremely low internal resistance (0.006Ω) of the carbon disc initiated excellent electrical conductivity. The supercapacitors also maintain their high capacitive properties in aqueous electrolyte solutions of 6 M KOH and 1 M Na₂SO₄, respectively. The results show that a novel consolidated carbon disc binder-free design can be obtained from biomass MOLs through a reasonable approach to develop superior electrode materials to enhance high-performance electrochemical energy storage devices.

Hemicellulosa-derived Arenga pinnata bunches as free-standing carbon nanofiber membranes for electrode material supercapacitors

Carbon nanofibers derived from lignocellulosic materials have become the most prevalent free-standing electrode material for supercapacitors due to their renewable and sustainable nature. This study used Arenga pinnata bunches (APB) as raw material for hemicellulose compounds to produce carbon electrodes through carbonization processes at 650 °C, 700 °C, 750 °C, and 800 °C, in the presence of flowing N₂ gas. The variations in carbonization temperature resulted in carbon electrodes with surface morphology having a nanofiber structure with micro-meso pore distribution. According to the results, the carbonization temperature of 700 °C (APB-700) is the optimum temperature for producing electrode surface morphology with a combination of nanofiber, micro-and mesopore distributions, as well as specific surface area, specific capacitance, energy density, and power density of 1231.896 m² g⁻¹, 201.6 F g⁻¹, 28.0 Wh kg⁻¹, and 109.5 W kg⁻¹, respectively, for the two electrode systems. This shows the combination of nanofibers and the distribution of micro-and mesopores produced with variations in carbonization temperature has the capacity to improve the performance of supercapacitor cells. Therefore, carbon nanofibers derived from Arenga pinnata bunches have the potential to be used as free-standing electrode materials for supercapacitors without employing doping, binder, electrospinning, and heteroatom template methods.

Three-dimensional pore structure of activated carbon monolithic derived from hierarchically bamboo stem for supercapacitor application

A three-dimensional pore structure on activated carbon derived from hierarchically bamboo stem was synthesized in the monolithic form for increased applicability as a supercapacitor electrode. The preparation involved two step carbonizations, using a chemical activation at different concentrations. Subsequently, the morphology, chemical content, specific surface area and pore size distribution, as well as crystalline degree were evaluated with scanning electron microscopy, energy X-ray (EDX), N2 sorption and X-ray diffraction, respectively. Therefore, cyclic voltammetry (CV) was used to assess the electrochemical performance, in a two electrode system. The result shows the significant impact of the three-dimensional structure on electrochemical performance, and the optimized sample exhibited specific capacitance of 168.8 F g-1, energy density of 23.44 Wh kg-1, and power density of 84.46 W kg-1.