High power supercapacitor electrodes based on flexible TiC-CDC nano-felts

Flexible electrospun titanium carbide (TiC) nano-felts were converted into carbide-derived carbon (CDC) by dry chlorination at temperatures between 200 and 1000 degrees C and used as binder-free supercapacitor electrodes. In the carbide nano-felt, TiC nano-crystals (20-30 nm) were embedded in a matrix of disordered carbon. After chlorination, the porous CDC nano-fibers/felts maintain their size, shape, and flexibility. With the increase of synthesis/chlorination temperature, the degree of carbon ordering increased. Electrochemical characterizations in 1 M H2SO4 and 1.5M tetraethylammonium tetrafluoroborate in acetonitrile were carried out on binder-free electrodes with galvanostatic cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. The highest gravimetric capacitance was identified for the CDC nano-felt synthesized at the highest temperature of 1000 degrees C, reaching 135 Fg(-1) in aqueous and 120 Fg(-1) in organic electrolytes. In contrast to powder or monolithic supercapacitor electrodes made of conventional activated, templated, or carbide-derived carbons, this material demonstrated excellent high-power handling ability: and similar to 50% of the low-rate capacitance was maintained at a very high scan rate of 5 Vs(-1). (C) 2011 Elsevier B.V. All rights reserved.