The unifying theme within this work is the production of porous activated carbon (AC) materials from different carbon-containing precursors for electrochemical supercapacitors (ES) applications. The activated carbon-based ES is an emerging storage technology that promises to play an important role in meeting the rising demands from the energy sector. Thus, it is necessary to study and produce various high-quality ACs by optimizing the micro/meso-porous architecture as electrodes and also study the effect of different electrolytes on the electrochemical behavior of the produced ACs. The produced ACs which are discussed in different sections in chapter 4 show specific surface area ranging from ~300 m2 g-1 to ~3000 m2 g-1, specific capacitances in the range of ~179 F g-1 to ~335 F g-1 and energy density in the range of ~15 Wh kg-1 to ~38 Wh kg-1 at a current density of 0.5 A g. Both symmetric and asymmetric devices also showed excellent long term stability and no capacitance loss after 10,000 charge discharge and the stable operating potential ranging from 1.2 V to 2 V depending on the electrolyte used. All devices kept the important property of supercapacitors which is a high power density even at low current densities. All the results presented above showed the great potential in the adoption of the synthesized activated carbon material for supercapacitor applications.