Hierarchical porous activated carbon derived from Enteromorpha prolifera for superior electrochemical capacitive behavior

A low-cost porous carbon material is introduced by using marine bloom green alga— Enteromorpha prolifera —as raw material towards simple freeze-drying pretreatment and subsequent ZnCl 2 activation procedure. This strategy is aimed at producing activated carbons with high surface area (1910.84 m 2 g −1 ) and combining macro-/meso-/micropores with high total pore volume (up to 2.86 cm 3 g −1 ), at a ZnCl 2 / E. prolifera impregnation ratio of 4 at 600 °C. The application of the activated carbons operating in electric double-layer capacitors (EDLCs) shows high specific capacitance of 332.4 F g −1 at a rate of 0.2 A g −1 in 1 M H 2 SO 4 , much better than those in 6 M KOH (167 F g −1 ). Moreover, the assembled symmetric devices yielded ultra-long cycling performance (100% after 5500 cycles at 0.5 A g −1 ). Benefiting from the cheap biomass precursor, we believe that this simple precursor synthesis route offers excellent potential for facile large-scale material production which may serve as a potential candidate for energy storage.