Influences from solvents on charge storage in titanium carbide MXenes

Xuehang Wang (1) , Tyler S. Mathis (1) , Ke Li (1) , Zifeng Lin (2, 3) , Lukas Vlcek (4, 5) , Takeshi Torita (6) , Naresh C. Osti (4) , Christine Hatter (1) , Patrick Urbankowski (1) , Asia Sarycheva (1) , Madhusudan Tyagi (7, 8) , Eugene Mamontov (4) , Patrice Simon (2, 9) , Yury Gogotsi (1)

1 Drexel University
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 SCU - Sichuan University [Chengdu]
4 ORNL - Oak Ridge National Laboratory [Oak Ridge]
5 UTC - University of Tennessee [Chattanooga]
6 Murata Manufacturing (JAPAN)
7 NIST Center for Neutron Research
8 University of Maryland [Baltimore]
9 RS2E - Réseau sur le stockage électrochimique de l'énergie

Pseudocapacitive energy storage in supercapacitor electrodes differs significantly from the electrical double-layer mechanism of porous carbon materials, which requires a change from conventional thinking when choosing appropriate electrolytes. Here we show how simply changing the solvent of an electrolyte system can drastically influence the pseudocapacitive charge storage of the two-dimensional titanium carbide, Ti3C2 (a representative member of the MXene family). Measurements of the charge stored by Ti3C2 in lithium-containing electrolytes with nitrile-, carbonate- and sulfoxide-based solvents show that the use of a carbonate solvent doubles the charge stored by Ti3C2 when compared with the other solvent systems. We find that the chemical nature of the electrolyte solvent has a profound effect on the arrangement of molecules/ions in Ti3C2, which correlates directly to the total charge being stored. Having nearly completely desolvated lithium ions in Ti3C2 for the carbonate-based electrolyte leads to high volumetric capacitance at high charge–discharge rates, demonstrating the importance of considering all aspects of an electrochemical system during development.

Mots clés: Solvent; Titanium carbide; Supercapacitor

Domaines: Matériaux; Energie électrique

Xuehang Wang, Tyler S. Mathis, Ke Li, Zifeng Lin, Lukas Vlcek, et al.. Influences from solvents on charge storage in titanium carbide MXenes. Nature Energy, 2019, 4 (3), pp.241-248. ⟨10.1038/s41560-019-0339-9⟩. ⟨hal-02360481⟩