Symmetric Supercapacitors Based on Multilayers of Conducting Polymers

The electrochemical and structural properties, charge capacitance, and stability upon oxidation-reduction cycling of multilayered systems based on alternated layers of different conducting polymers have been analyzed. Parallel studies have been carried out on individual conducting polymers for comparison. In all cases, the capacitive properties of multilayered systems were better than those of individual conducting polymers, which have been attributed to both the synergistic effects at the interfaces between consecutive layers and the higher porosity of the multilayered materials. Moreover, after hundreds of consecutive oxidation-reduction processes, the porosity in multilayered systems remained relatively high, whereas it was moderate or even null in the individual materials, this difference being crucial to understanding the very different electrochemical degradation of the specific capacitance observed for these materials. Multilayered systems have been used to fabricate a supercapacitor in the type I configuration (symmetric assembly of two identical electrodes), which has been found to present a very high specific capacitance.