Supercapacitors

Persons in charge: Pierre-Henri Aubert

Positive electrodes of supercapacitors have been developed as hybrid nanocomposites, from the nanostructuring of electronic conductive polymer (PCE) and using aligned carbon nanotubes (NTCa).

The main issue was to precisely control the PCE deposition along the NTCa by electrosynthesis in an ionic liquid medium. Thus, a sequenced electrosynthesis process allows diffusion of the monomer to the electrodes of the NTCa, which can then be coated homogeneously.

Electropolymerization of 3-methylthiophene along NTC.
Picture by scanning electron microscopy of NTCa after electropolymerization.

The nanostructured material’s capacity is increased by 35% from 95F/g without NTCa to 126F/g in the case of the nanocomposite. This process has been extended to other PCEs such as polypyrrole, PEDOT, polycarbazole and polythiophene, but also to their copolymers. In addition, and under special synthesis conditions, the hybrid nanocomposite is obtained as a self-supporting and flexible conductive film.

Furthermore, separator membranes for supercapacitors are also developed from POE based materials and ionic fluid inflated elastomers. These membranes perform over a wide range of temperatures (-60°C – 100°C).