Free-standing carbon nanofiber fabrics for high performance flexible supercapacitor

Abstract

Free-standing carbon nanofiber fabrics with high surface area and good flexibility were prepared via a combined electrospinning and nanocasting method using low molecular weight phenolic resol as carbon precursor and partial-hydrolyzed tetraethyl orthosilicate as template, followed by carbonization and silica removal. The key to our strategy lies in the formation of a stable electrospinning solution derived from the polycondensation of partial-hydrolyzed TEOS in mild hydrolysis with low molecular phenolic resol and PVB which could decrease the gelation rate to benefit for the steady electrospinning process of preparing large area hybrid nanofiber fabrics. The obtained carbons possess high specific surface area up to 2292 m2/g with a large pore volume of 1.02 cm3/g. As flexible electrodes, these carbon nanofiber fabrics could deliver high specific capacitance up to 274 F/g at 0.1 A/g in H2SO4 electrolyte and 220 F/g at 0.5 A/g in solid-state supercapacitor with good rate and cyclic performance. These outstanding advantages of carbon nanofiber fabrics, including their well-developed microporosity, easily tailored pore structure, good mechanical strength and flexibility, endow them with great potential for application in flexible energy storage devices.