Ball milling-assisted synthesis and electrochemical performance of porous carbon with controlled morphology and graphitization degree for supercapacitors

Porous carbons are considered as promising electrode materials for electrical double layer capacitors due to their high surface area, abundant pores and high conductivity. However, the preparation of porous carbons with controlled morphology and graphitization degree is still a challenge, since the structure of the precursor tends to collapse and the amorphous carbon tends to form during the synthesis process. Herein, an efficient ball milling-assisted method for the preparation of porous carbons with controlled morphology and graphitization degree is developed. The results show that the amount of FeCl3·6H2O determines the morphologies, graphitization degree and yield of porous carbons. The as-prepared porous carbon exhibits a superior specific capacitance of 168 F g−1 at 1 A g−1 and a good cycling stability of a 94.7% capacitance retention after 10,000 cycles when used as supercapacitor electrode materials. The excellent electrochemical performance is attributed to the high surface area (992 m2 g−1) and rich micropores, which can supply more active sites and ensure high specific capacitance. The abundant mesopores and high graphitization degree can accelerate the electron transfer and the ion diffusion within the electrodes. In addition, the thin sheets can also shorten the ion diffusion and electron transfer length.