Phase stability frustration on ultra-nanosized anatase TiO(2)

This work sheds light on the exceptional robustness of anatase TiO(2) when it is downsized to an extreme value of 4 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 1000 °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.