Lithium insertion into nanometer-sized rutile-type Ti_xSn_{1 - x}O₂ solid solutions

The electrochemical properties of rutile-type Ti_xSn_1-xO₂ solid solutions (x = 0-1.0) as an anode for a lithium-ion battery were investigated using nanosized crystals prepared by an aqueous solution process. The reduction of the crystal size to nanoscale allowed a smooth lithium insertion into the rutile framework at room temperature. The lithium-insertion behavior of TiO₂, SnO₂, and the solid solutions was evaluated without any structural change of the rutile-type crystal structure in the potential range of 1.2-3.5 V (versus Li/Li⁺). The interstitial spaces for lithium ions were found to be derived from the crystal structure of the rutile framework and independent of the metal species.