Dual lithium insertion and conversion mechanisms in a titanium-based mixed-anion nanocomposite

Damien Dambournet (1) , Karena W. Chapman (2) , Peter J. Chupas (2) , Rex E. Gerald (1) , Nicolas Penin (3) , Christine Labrugere (3) , Alain Demourgues (3) , Alain Tressaud (3) , Khalil Amine (1)

1 Chemical Sciences and Engineering
2 XSD - X-ray Science Division
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

The electrochemical reaction of lithium with a vacancy-containing titanium hydroxyfluoride was studied. On the basis of pair distribution function analysis, NMR, and X-ray photoelectron spectroscopy, we propose that the material undergoes partitioning upon initial discharge to form a nanostructured composite containing crystalline Li(x)TiO(2), surrounded by a Ti(0) and LiF layer. The Ti(0) is reoxidized upon reversible charging to an amorphous TiF(3) phase via a conversion reaction. The crystalline Li(x)TiO(2) is involved in an insertion reaction. The resulting composite electrode, Ti(0)-LiF/Li(x)TiO(2) ⇔ TiF(3)/ Li(y)TiO(2), allows reaction of more than one Li per Ti, providing a route to higher capacities while improving the energy efficiency compared to pure conversion chemistries.

Domaines: Matériaux

Damien Dambournet, Karena W. Chapman, Peter J. Chupas, Rex E. Gerald, Nicolas Penin, et al.. Dual lithium insertion and conversion mechanisms in a titanium-based mixed-anion nanocomposite. Journal of the American Chemical Society, 2011, 133 (34), pp.13240-13243. ⟨10.1021/ja204284h⟩. ⟨hal-00626975⟩