Thus, it has been suggested that heteroatom such as oxygen and nitrogen functionalities are proved to be beneficial for the augmented energy storage performance of carbon-based materials. Also, 93% of capacitance retained for the PAC-4-700 electrode after 10000 cycles carbon at 600, 700 and 800 °C are found to be 356, 410 and 220 F g -1 at 0.5 A g -1 in 1 M H2SO4, respectively. The maximum capacitance was observed for the material formed at 700 °C (AV-700) suggesting that the interaction between oxygen functionalities such as epoxy and carbonyl oxygen with protons from sulphuric acid was efficient at this temperature. On other hand if the temperature is enhanced to 800 °C, then it was found that the capacitance was decreased because oxygen functionalities are reduced if the temperature is higher than 700 °C and hence it was not able to participate faradaic interaction with ions from acidic electrolyte during electrochemical cycling. XPS deconvoluted O1s spectrum of AV-700 revealed the more carbonyl and epoxy oxygen functionalities are existed. The methodology in the preparation using activation by KOH as well as trend in capacitance with respect to temperature was also followed in porous activated carbon derived from other wastes such as orange peel, corn cob, cauliflower, Thespesia Populnea seeds, beetroot peel reported by the same group .