Supercapacitive behavior depending on the mesopore size of three-dimensional micro-, meso- and macroporous silicon carbide for supercapacitors

Three-dimensional silicon carbide-based frameworks with hierarchical micro-, meso-, and macroporous structures (3MPSiC) were prepared by a template method with subsequent carbonization via an aerosol spray drying method. The micropores were derived from partial vaporization of Si atoms during the carbonization process, whereas the meso-and macropores were generated by self-assembly of the structure directing agent and polystyrene latex spheres, respectively. The effect of the mesopore size on the electrochemical performance of 3MPSiC electrodes was evaluated by fabricating three types of 3MPSiC samples with different mesopore size by using three different structure directing agents (cetyltriethylammonium bromide (CTAB), polyethylene glycol hexadecyl ether (Brij56), and poly(ethylene glycol)-block-poly(propylene glycol)-blockpoly( ethylene glycol) (P123)). The 3MPSiC electrode prepared using Brij56 exhibited outstanding electrochemical performance with a specific capacitance of 336.5 F g(-1) at a scan rate of 5 mV s(-1) with 90.3% rate performance from 5 to 500 mV s(-1) in 1 M Na2SO4 aqueous electrolyte. The outstanding electrochemical performance is attributed to the ideal mesopore size that can effectively reduce resistant pathways for ion diffusion in the pores as well as provide a large accessible surface area for ion transport/charge storage. These encouraging results demonstrate the high potential of 3MPSiC prepared using Brij56 for application as a highperformance electrode material for supercapacitors.