Solvothermal Synthesis Of Electrochemically Active Nanocrystalline Li-Ti-O Spinel

Nanocrystalline Li-Ti-O spinel samples were prepared by solvothermal reaction of TiO2 with lithium hydroxide in water and ethanol. The hydrothermal reaction proceeds at temperature higher than 130 deg C. The reaction proceeds via dissolution-precipitation mechanism and its course is not sensitive to titanium dioxide polymorph used in the reaction. Product of the reaction in water has cubic rock salt type structure. It converts, however, to spinel if annealed to temperatures exceeding 250 deg C. The re-crystallization is accompanied with water removal from the structure. Solvothermal reaction in ethanol leads directly to a product with spinel structure without need for annealing. Both products are active for Li insertion the electrochemical activity. The specific capacity ranges between 100 and 160 mAhg depending on the annealing temperature.