The electrical double-layer supercapacitance performance of the nanoporous carbons prepared from the Phyllanthus emblica (Amala) seed by chemical activation using the potassium hydroxide (KOH) activator is reported. KOH activation was carried out at different temperatures (700–1000 °C) under nitrogen gas atmosphere, and in a three-electrode cell set-up the electrochemical measurements were performed in an aqueous 1 M sulfuric acid (H2SO4) solution. Because of the hierarchical pore structures with well-defined micro- and mesopores, Phyllanthus emblica seed-derived carbon materials exhibit high specific surface areas in the range of 1360 to 1946 m2 g−1, and the total pore volumes range from 0.664 to 1.328 cm3 g−1. The sample with the best surface area performed admirably as the supercapacitor electrode-material, achieving a high specific capacitance of 272 F g−1 at 1 A g−1. Furthermore, it sustained 60% capacitance at a high current density of 50 A g−1, followed by a remarkably long cycle-life of 98% after 10,000 subsequent charging/discharging cycles, demonstrating the electrode’s excellent rate-capability. These results show that the Phyllanthus emblica seed would have significant possibilities as a sustainable carbon-source for the preparing high-surface-area activated-carbons desired in high-energy-storage supercapacitors.

The development of human society has been driven by new materials that have been created one after another 1) . In particular, various scientific fields have been systematized since the 20th century, and these have accelerated the advancement of new functional materials. Recent reviews and research results show that organic chemistry 2−4) , inorganic chemistry 5−7) , polymer chemistry 8−10) , coordination

Here we report the methylene blue adsorption and energy storage supercapacitance performances of the nanoporous activated carbons obtained by the zinc chloride (ZnCl2) activation of biowaste, Terminalia bellirica (Barro) seed stone. The activation was performed at lower temperatures (400–700 °C) under an inert nitrogen gas atmosphere. The total specific surface area and pore volume range from 1077 to 1303 m2 g−1 and 0.752 to 0.873 cm3 g−1, depending on the carbonization temperature. Due to the well-developed porosity, the sample with optimal surface area showed excellent iodine and methylene blue adsorption properties with a maximum iodine number and methylene blue value of 909.8 mg g−1 and 357.2 mg g−1, respectively. Batch adsorption studies revealed that the optimum methylene blue adsorption is favorable in an alkaline medium, with a contact time of 270 min and an adsorbent dose of 8 g L−1, respectively. The Langmuir isotherm model could best explain the equilibrium adsorption with a monolayer adsorption capacity of 312.5 mg g−1. The electrochemical measurements performed in a three-electrode system revealed a high specific capacitance of 319 F g−1 at 1 A g−1. Furthermore, the electrode retained 46% capacitance at 50 A g−1 with an excellent cycle life of 98.5% after 10,000 consecutive charging/discharging cycles. These results imply that a biowaste Terminalia bellirica seed has a considerable potential to produce high surface area porous carbons materials desired in adsorption technology and high-performance supercapacitor applications.

Porous activated carbon materials derived from biomass could be the suitable materials for high-rate performance electrochemical supercapacitors as it exhibits high surface area due to well-defined pore structure. Here, we report the novel porous activated carbon from Triphala seed stones by chemical activation with zinc chloride at different carbonization temperature (400-700 °C) under the nitrogen gas atmosphere. The activated carbon was characterized by Fourier transform-infrared (FTIR) spectroscopy, Raman scattering and scanning electron microscopy (SEM). Nitrogen adsorption-desorption measurements was used to study the surface properties (effective surface areas, pore volumes and pore size distributions). The electrochemical measurements were performed in an aqueous 1 M sulphuric acid (H2SO4) solution in a three-electrode cell set up. Triphala seed stones-derived porous carbon materials with well-defined micro- and mesopores exhibit high specific surface area ranges from 878.7 to 1233.3 m2 g-1 and total pore volume ranges from 0.439 to 0.626 cm3 g-1. The specific capacitance obtained by electrochemical measurement experiment was 208.7 F g-1 at 1 A g-1. These results indicate that the prepared nanoporous activated carbon material from Triphala seed stones would have significant possibility as supercapacitor electrode material for high-energy-storage supercapacitor applications.

Carbonized C60 nanospheres efficiently improve the mechanical properties and supercapacitor performance when they are added to a poly(vinyl alcohol)/TEMPO-cellulose hydrogel-based electrolyte.