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 (CO2), 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 H2SO4. 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.