Supercapacitors’ electrodes with high volumetric capacitance
The design of new materials for electrochemical energy storage is one of the major challenges to improve the overall autonomy of on-board devices. Among those devices, supercapacitors offer performances in-between those of batteries and capacitors: high power density but limited energy density. Increasing this energy density could led to improve autonomy, limited to a few seconds nowadays.
Following their research projects on carbon materials for electrochemical energy storage, researchers of CIRIMAT lab (UMR CNRS 5085) at Paul Sabatier University (Y. Dall’Agnese, P. Rozier, P. L. Taberna and P. Simon) displayed the ability to insert in a reversible manner different ions in aqueous media – sodium, potassium, ammonium, magnesium and aluminum – inside layered carbides structures named « MXenes ». More precisely, the insertion of ions coming from an aqueous electrolyte was demonstrated using layered structured titanium carbides (Ti3C2) whose surface is functionalized by hydrophilic groups.
These results, obtained in joint collaboration with Y. Gogotsi and M. Barsoum’s team (Drexel University), are interesting on different levels. First and foremost, few materials accept the insertion of ions bigger than lithium; secondly, the displayed volumetric charge storage capacities are two to three times higher than those previously reported, this being a major step forward toward crafting high energy density supercapacitors. More broadly, those researches offer the possibility to explore the whole layered carbides and carbonitrides MXene type family for electrochemical energy storage systems through monovalent and multivalent ions insertion to improve their performances.
Cation Intercalation and High Volumetric Capacitance of Two-dimensional Titanium Carbide. M. R. Lukatskaya, O. Mashtalir, C. E. Ren, Y. Dall’Agnese, P Rozier, P L Taberna, M. Naguib, P. Simon, M. W. Barsoum & Y. Gogotsi
Science, Report, 27th September, DOI: 10.1126/science.1241488.