Abstract
Single crystals of Li4+xTi5O12 were prepared by means of electrochemical Li-ion intercalation technique using parent Li4Ti5O12 single crystals. The obtained Li4+xTi5O12（x＝1.35）crystallizes in the cubic spinel-related type structre, space group Fd3m, and lattice parameters of a＝8.346（3）Å and V＝581.3（5）Å3. The Li-ion intercalated sites were successfully determined by single crystal X-ray diffraction. From the result, because of the structural restriction of the spinel structure, unfortunately, the theoretical capacity was revealed to be 175 mAh/g. New material Li2Ti6O13 with rectangular tunnels was synthesized by Na+/Li+ ion-exchange method as one of the negative electrode material having a high capacity than Li4Ti5O12. The Li2Ti6O13 as determined the precise crystal structure by powder neutron diffraction and evaluated reversible Li insertion/extraction reaction.
