Porous carbon thin films for electrochemical capacitors
Abstract
Activation effects on carbon films, derived from commercial aromatic polyimide films (Kapton, DuPont), in CO2 atmosphere at 1203 K on capacitance properties were studied. Two thicknesses of polyimide films were used: 7 and 25 gm. Pore formation during the activation process progresses in two steps due to the existence of a denser surface layer and a more porous core material. In the first step micropores are opening in the dense surface region of the material with average pore diameter smaller than 1 nm. During the second step, mesopores start opening, while micropore volume remains constant with the average micropore diameter of over 1 nm, producing bimodal texture. The first step finishes after 30 min for the thinner samples while for the thicker samples it finishes after 60 mm of activation. As a consequence of such textural changes during activation, the thicker sample has a maximum areal capacitance of 0.35 F/cm(2). The thinner sample activated for 30 min has a maximum volumetric ...capacitance of 220 F/cm(3) and achieves a maximum gravimetric capacitance of 240 F/g when the texture becomes bimodal after 240 min of activation. These results confirm that activation of carbonized Kapton films gives promising electrode materials for supercapacitors.
Source:
Carbon, 2013, 64, 456-463Publisher:
- Pergamon-Elsevier Science Ltd, Oxford
Projects:
- Physics and Chemistry with Ion Beams (RS-45006)
- Nanostructured Functional and Composite Materials in Catalytic and Sorption Processes (RS-45001)
- Joint Institute for Nuclear Research (JINR), Dubna, Russian Federation
- Ministry of Education and of the Republic of Serbia
DOI: 10.1016/j.carbon.2013.07.098
ISSN: 0008-6223