Singlewall carbon nanotubes were covered with polypyrrole via in situ miniemulsion polymerization of pyrrole monomer. They had nanotube surfaces partially enveloped with polypyrrole: the surfaces attached with polypyrrole particles, the surfaces covered with thin polypyrrole film, and bare surfaces. The nanotubes covered with polypyrrole were doped with LiClO4 and mixed with a binder, Kynar FLEX 2801, to make composite electrode for supercapacitor. The pelletized powder of the composite with Li+ ions exhibited higher electrical conductivity and lower percolation threshold concentration than pristine polypyrrole. The composite was used to fabricate the electrode in supercapacitor without adding other conducting material like carbon black. It showed higher specific capacitance than polypyrrole/binder/carbon black composite. This could be explained due to the existence of bare surfaces of SWNTs with high electrical conductivity as well as large surface area. (c) 2005 Elsevier Ltd. All rights reserved.