The present invention provides a process for making activated carbon having BET surface area up to 2000 m2/g with pore diameter in the range 17-21 Å suitable for fabricating fuel cell and ultracapacitor electrode from coconut shell by treating carbon granules obtained from coconut shells with chemical activating agents like zinc chloride or potassium hydroxide at the room temperature range 500-800° C. in a dynamic flow of gases like N2 or CO2 for 6-24 h followed by a specific cooling pattern to room temperature. Use of such activated carbon enables the fabrication of high performance ultracapacitor electrodes in H2SO4 as exemplified by capacitance values like 180 F/g without the use of any normal metal additives such as RuO2 or IrO2.