Compositional Tuning of Structural Stability of Lithiated Cubic Titania via a Vacancy-Filling Mechanism Under High Pressure

Hui Xiong, Argonne National Laboratory
Handan Yildirim, Argonne National Laboratory
Paul Podsiadlo, Argonne National Laboratory
Jun Zhang, Argonne National Laboratory
Vitali B. Prakapenka, University of Chicago
Jeffrey P. Greeley, Argonne National Laboratory
Elena V. Shevchenko, Argonne National Laboratory
Kirill K. Zhuravlev, University of Chicago
Sergey Tkachev, University of Chicago
Subramanian K. R. S. Sankaranarayanan, Argonne National Laboratory
Tijana Rajh, Argonne National Laboratory


Experimental and theoretical studies on the compositional dependence of stability and compressibility in lithiated cubic titania are presented. The crystalline-to-amorphous phase transition pressure increases monotonically with Li concentration (from ∼17.5 GPa for delithiated to no phase transition for fully lithiated cubic titania up to 60 GPa). The associated enhancement in structural stability is postulated to arise from a vacancy filling mechanism in which an applied pressure drives interstitial Li ions to vacancy sites in the oxide interior. The results are of significance for understanding mechanisms of structural response of metal oxide electrode materials at high pressures as well as emerging energy storage technologies utilizing such materials.