High-frequency carbon supercapacitors from polyfurfuryl alcohol

Porous carbons with controllable and narrow pore-size distributions are prepared from the chemical activation of polyfurfuryl alcohol (PFA). High apparent BET surface areas, up to 2600 m(2) g(-1) (2611 m(2) g(-1) by Density Functional Theory (DFT)), and good electrical conductivities (up to similar to 130 S cm(-1)) are obtained. By varying the potassium hydroxide: carbon precursor ratio, the preparation of carbons with different proportions of micro- and fine mesoporosity (<5 nm) can be tailored to provide an ideal electronic and ionic pore structure for electrochemical energy-storage devices, such as electrical double-layer capacitors. High specific capacitance values are obtained up to 147 Fg(-1) in a voltage window of 2.5V using 1 M tetraethyl ammonium tetrafluoroborate in acetonitrile. Moreover, excellent high-current and high-frequency performance is demonstrated: 100 Fg(-1) at 225 A g(-1) (10 Hz) and similar to 30 Fg(-1) at 100 Hz. When comparing the performance with commercial activated carbons (ACs) of similar textural properties, the PFA-derived ACs demonstrated better performance in terms of higher capacitance values and improved rate capabilities. There is a 125% increase in capacitance values at 1 kHz. (C) 2011 Published by Elsevier B.V.