3. Objective of increasing energy density

Today, while the power performance of supercapacitors is satisfactory for most applications, the same cannot be said for energy. In fact, many transport applications (hybrid vehicles, tramways, etc.) require charging or discharging times of the order of ten seconds. This explains why most of today's research is focused on increasing the energy density of supercapacitors. Various strategies can be envisaged to achieve this objective:

• the functionalization of carbons by functional groups offering the possibility of surface redox reactions;

• system-level hybridization: a carbon/carbon...