Zero‐Strain Insertion Material of Li [ Li1 / 3Ti5 / 3 ]  O 4 for Rechargeable Lithium Cells

having a defect spinel‐framework structure was prepared and examined in non‐aqueous lithium cells. (white in color) was reduced to (dark blue) at a voltage of 1.55 V and the reaction was highly reversible. X‐ray diffraction measurements indicated that the lattice dimension did not change during the reaction