Hierarchical porous carbon fibers prepared using a SiO2 template for high-performance EDLCs

A simple method for preparing hierarchical porous carbon fibers with micropores and mesopores was developed using electrospun PAN (polyacrylonitrile) fibers, a SiO2 (silica) template, and KOH (potassium hydroxide) activation. The diameter of well-developed hierarchical porous carbon fibers was presented 500 nm and 1 μm by using FE-SEM. The prepared hierarchical porous carbon fibers had high specific surface areas (1625–1796 m2/g) and hierarchical pore structures with micropore (below 2 nm), mesopore (2–5 nm, and 10–50 nm), and macropore (>50 nm). The hierarchical porous carbon fibers were used as electrodes in electric double-layer capacitors (EDLCs) to measure the specific capacitance and retained capacitance ratio. This unique hierarchical pore structure had a synergistic effect, resulting in excellent specific capacitances (197 and 172 F/g at scan rate 5 and 50 mV/s, respectively) and retained capacitance ratios improved from 60.8% to 87.3%. The enhanced EDLC performance demonstrates the potential of hierarchical porous carbon fibers prepared with a SiO2 template and KOH activation.