Nitrogen doped activated carbons have been fabricated by simultaneous carbonization and KOH activation of chitosan biomass regenerated from prawn shell at high temperature. Sufficient porosity with high content of nitrogen heteroatom makes them very appealing for charge storage in supercapacitors. Specifically, the activated carbon obtained at 700 degrees C shows excellent capacitive performance in both acidic and alkaline electrolyte in virtue of the optimized combination of electronic double-layer capacitance and pseudo-capacitance. It exhibits high specific capacitance of 695 F g (1) in 1 M H2SO4 and 357 F g (1) in 6 M KOH at a current density of 50 mA g (1). Even cycled at high current density of 5 A g (1), high capacitance of over 280 F g 1 can be still retained in both electrolytes. Stable capacitance retention over 95% for as long as 5000 cycles is also achieved at 1 A g (1) in both cases. (C) 2016 Elsevier Ltd. All rights reserved.