Theoretical and practical energy limitations of organic and ionic liquid-based electrolytes for high voltage electrochemical double layer capacitors

Abstract In EDLCs the energy is stored in the double layer formed by the ions of the electrolyte. Hence, during charge–discharge the ion concentration changes and therefore also the electrolyte should be considered as active material. In the past it has been shown that the performance of EDLCs based on non-aqueous electrolytes is mainly limited by ion concentration of the electrolytes. Taking this point into account, we considered the influence of the salt concentration on the theoretical and practical energy of high voltage EDLCs containing innovative electrolytes with the aim to understand the advantages and the limits related to their use.