Molten salt electrolytic synthesis of porous carbon from SiC and its application in supercapacitors

Nanoscale porous carbide-derived carbon (CDC) microspheres were successfully synthesized via the electrolysis etching of nano-SiC microsphere powder precursors with a particle diameter of 200 to 500 nm in molten CaCl₂. Electrolysis was conducted at 900 °C for 14 h in argon at an applied constant voltage of 3.2 V. The results show that the obtained product is SiC-CDC, which is a mixture of amorphous carbon and a small quantity of ordered graphite with a low degree of graphitization. Similar to the SiC microspheres, the obtained product retained its original shape. The specific surface area was 734.68 m² g^-1. The specific capacitance of the SiC-CDC was 169 F g^-1, and it exhibited excellent cycling stability (98.01% retention of the initial capacitance after 5000 cycles) at a current density of 1000 mA g^-1.