Supercapacitors are electrochemical energy storage systems that offer intermediate performance between batteries and capacitors. They are capable of delivering high power for times of tens of seconds, making them complementary to batteries.
Supercapacitors store charge by reversible adsorption of electrolyte ions in porous carbon electrodes with large surface areas (> 1,000 m² - g-1). The interface between the porous electrode and the electrolyte therefore plays a central role in these systems, since it is here that most of the reactions involved take place, i.e. charging of the electrochemical double layer through ion adsorption, ion exchange and desolvation. The importance of this interface is further reinforced by the nanometric size of the pores in carbon electrodes, where the confinement of the electrolyte in these nanopores will lead to specific structuring effects.
In this talk, we have shown how controlling the electrode/electrolyte interface in supercapacitor electrodes has first improved our fundamental understanding of ion adsorption and transport in confined media. We drew on results obtained from a variety of experimental and modeling techniques. From a more practical point of view, these results have enabled us to improve the charge storage capacity of these electrodes, thereby enhancing the energy density of supercapacitors.
