Synthesis and Lithium Insertion into Nanophase MgTi2O5 with Pseudo-Brookite Structure

Micrometer-sized and nanometer-sized samples of MgTi 2 O 5 were prepared by solid state reaction and polymerizable complex methods. Electrochemical lithium insertion was studied for the first time. We observe a remarkable change in the material response when particle size is reduced from micrometer to nanometer regime. In micrometer sized samples, 0.8 Li per formula unit could be inserted, and no reversible extraction of lithium is observed. In case of nanometer-sized samples, 2.1Li are inserted and 1Li can be reversibly extracted even after 50 cycles. In the case of nanometer sized samples, formation of a new phase with approximate composition Li 2 MgTi 2 O 5 is evident form ex situ XRD studies. HRTEM studies reveal that the new phase can be considered as a distorted analogue of the parent phase.