| abstract |
Provided is a lithium titanate powder for an electrode of a power storage device, which contains Li 4 Ti 5 O 12 as a primary component and which is characterized in that when D BET denotes the diameter equivalent to a specific surface area, as calculated from the specific surface area determined by the BET method, and D X denotes the crystal grain diameter, as calculated from the half value width of a peak of the (111) face of Li 4 Ti 5 O 12 using the Scherrer equation, D BET is 0.1-0.6 μm, D X is greater than 80 nm, and the ratio of D BET and D X (D BET /D X ) (μm/μm) is 3 or lower, M (here, M is at least one type of metal element selected from among Mg, Zn, Al, Ga and In) is contained, and if D1 (atm%) denotes the concentration of M atoms and Dti (atm%) denotes the concentration of titanium atoms at positions 5 nm and 100 nm towards the inside from the surface of the lithium titanate particle and D2 (atm%) denotes the concentration of M atoms at positions of 5nm and 100 nm towards the inside from the surface of the lithium titanate particle, formulae (I) and (II) are satisfied; Also provided are an active substance material containing same, and a power storage device that uses this active substance material. D1/D2 ≥ 5 (I) 0.02 ≤ D1/Dti ≤ 0.4 (II) |