Activated Carbon Prepared from Rose Branch using H₃PO₄- hydrothermal Carbonization and Activation and its Apllication for Supercapacitors

摘要

Charcoals of rose branch were prepared by the three different carbonization treatments: phosphoric acidhydrothermal method, traditional hydrothermal method and pyrolysis. Then these charcoals wereactivated under the same conditions to obtain activated carbons. It is found phosphoric acid plays twomajor roles: (1) improving the specific surface area and the pore volume of the charcoals; (2) increasingthe reactivity of the charcoals, making charcoals easier to be activated. Electrodes using activatedcarbons from different carbonization methods were prepared, and electrochemical measurements wereperformed with a three-electrode cell using 1 M Na 2 SO 4 as the electrolyte. Activated carbons preparedby conventional hydrothermal carbonization showed the lowest capacitance (137 F / g, at 0.2 A / g) andcapacity retention (72.79%, at 2 A / g); while activated carbon prepared by phosphoric acid hydrothermalcarbonization showed the highest specific capacitance (178 F / g, at 0.2 A / g) and capacity retention(91.01%, at 2 A / g).