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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.

Carbonization and activation have been exploited as an economic and efficient approach toward the production of porous activated carbon monolith derived from green stem of cassava (GSC). In addition, ZnCl 2 was used as a chemical activator agent at various concentrations, therefore serving as a key factor in the development of porous carbon. The carbonization process (N 2) was integrated with physical activation (CO 2), and then N 2 sorption, scanning electron microscopy, X-ray diffraction, energy dispersive X-ray were examined to evaluate the specific surface area, pore structure characteristic, morphology structure, crystallinity, and the surface element, respectively. Furthermore, cyclic voltammetry was used to measure the electrochemical performance, through a two-electrode system in 1M H 2 SO 4. Therefore, the synthesized porous activated carbon exhibits a micropores-mesopores combination, and the optimized sample demonstrated nanosheet and nanofiber structures. The results show a high electrochemical behavior in 1M H 2 SO 4 electrolytes, by the electrodes, with specific capacitance, energy, and power densities of 164.58 F g −1 , 22.86 Wh kg −1 , and 82.38 W kg −1 , respectively. This route confirms the opportunity of using novel GSC in the production of porous carbon monolith with nanosheet/nanofiber structure for supercapacitor applications. K E Y W O R D S activated carbon, carbon porous, green stem of cassava, monolith, supercapacitor 1 | INTRODUCTION Green, renewable, and sustainable sources of energy systems are obtainable through the conversion of wind, water, and solar energy, 1 hence proper capture and storage is required for environmental friendly and economic application. 2 Meanwhile, supercapacitors possessing high power density, high charge-discharge rate, long cycle life, have the ability to store energy in the form of electric charges, 3 by providing a performance between capacitors and batteries. Conversely, the difference between both is that capacitors store and deliver energy incredibly quickly, while batteries have an ability to store high energy densities and also high voltages. 4 However, the main challenge of supercapacitor is related to the energy density entry through the narrow gap of batteries. Several electrode materials have been developed and suggested to improve energy density, power density, and cycle life of supercapacitor, 5 and three types were identified. These were then classified into carbonaceous

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Preparation and characterizations of activated carbon monolith from rubber wood and its effect on supercapacitor performances AIP Conference Proceedings 1712, 050011 (2016) Abstract. Seven types of activated carbon electrode (ACM) have been produced from the banana peel waste for supercapacitor application. The difference type of the electrode was synthesized by the various conditions of carbonization and activation. The production of the ACM was begun by the milling process and molded by a solution casting technique. The next step was followed by drying, carbonization and activation process. Physical properties of the ACM were studied by the N2 gas absorption-desorption method to characterize the specific surface area of the sample. On the other side, the electrochemical properties such as specific capacitance (Csp), specific energy (E) and specific power (P) were resulted by calculating the current (I) and voltage (V) data from the cyclic voltammetry testing. Based on the data obtained the surface area of the ACM has a significant relationship with the electrochemical properties. The specific surface area (SBET), Csp, E and P were found the maximum value as high as 581m 2 / g, 68 F/g, 0.75 Wh/kg and 31 W/kg, respectively. Further more, this paper were also analyzed the relationship between electrochemical properties of supercapacitor with the degree of crystallization of the ACM.