Rational design of meso-/micro-pores for enhancing ion transportation in highly-porous carbon nanofibers used as electrode for supercapacitors

Abstract

Carbon nanofiber has been one of the promising electrode materials for supercapacitors. It is desirable but still challenging to optimize meso-/micro-pore ratio and configuration while achieving a high specific surface area in carbon nanofibers. Here, we present the design and preparation of carbon nanofiber mats with both high specific surface area and rational meso-/micropore configuration by electrospinning tetraethyl orthosilicate (TEOS)/phenolic resin (PR)/polyvinylpyrrolidone (PVP)/F127 blend solution, followed by carbothermal reduction, removal of carbon and chlorination. Silicon carbide nanofibers constructed by regulatable secondary nanostructure were achieved by adjusting TEOS content in the spinning solution, derived from which microporous carbon nanofibers with considerable mesopores (60–70% in mesoporosity), diverse secondary nanostructure (24–44 nm), and high specific surface area (1765–1890 m2 g−1) were prepared. The formation mechanism of the diverse secondary nanostructure in carbon nanofiber was proposed. The carbide-derived carbon nanofibers showed an excellent specific capacitance (316 F g−1 at 0.1 A g−1) and high-rate capability (186 F g−1 at 100 A g−1) due to the enhanced ion transportation, which was achieved by shortening micropore channels and offering convenient mesoporous channel towards microporous domains.