Phase stability frustration on ultra-nanosized anatase TiO 2

S. Patra , C. Davoisne (1, 2) , Houssny Bouyanfif , Dominique Foix (3, 1, 4) , F. Sauvage

1 RS2E - Réseau sur le stockage électrochimique de l'énergie
2 LRCS - Laboratoire réactivité et chimie des solides - UMR CNRS 7314
3 ALISTORE-ERI - Advanced Lithium Energy Storage Systems - ALISTORE-ERI
4 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

This work sheds light on the exceptional robustness of anatase TiO 2 when it is downsized to an extreme value of 4â €‰nm. Since at this size the surface contribution to the volume becomes predominant, it turns out that the material becomes significantly resistant against particles coarsening with temperature, entailing a significant delay in the anatase to rutile phase transition, prolonging up to 1000â €‰°C in air. A noticeable alteration of the phase stability diagram with lithium insertion is also experienced. Lithium insertion in such nanocrystalline anatase TiO 2 converts into a complete solid solution until almost Li 1 TiO 2, a composition at which the tetragonal to orthorhombic transition takes place without the formation of the emblematic and unwished rock salt Li 1 TiO 2 phase. Consequently, excellent reversibility in the electrochemical process is experienced in the whole portion of lithium content.

Domaines: Matériaux; Chimie théorique et/ou physique

S. Patra, C. Davoisne, Houssny Bouyanfif, Dominique Foix, F. Sauvage. Phase stability frustration on ultra-nanosized anatase TiO 2. Scientific Reports, 2015, 5, ⟨10.1038/srep10928⟩. ⟨hal-01684677⟩