| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrode active material for a lithium ion secondary battery, capable of achieving excellent characteristics.SOLUTION: An electrode active material for a lithium ion secondary battery comprises particles mainly containing a bronze type titanium oxide, and has a specific surface area measured by a BET method of 8-45 m/g and the following crystallographic features measured by a powder X-ray diffraction method. The half-value width FWHMa of a diffraction peak of the (110) plane at a diffraction angle 2&thetas; of around 25° in XRD is in the range of 0.2°-0.5°. FWHMb/FWHMa, where the half-value width of a diffraction peak of the (003) plane at a diffraction angle 2&thetas; of around 43.5° is denoted as FWHMb, is in the range of 1.1-2.0. When the integrated intensity of a diffraction peak of the (110) plane at a diffraction angle 2&thetas; of around 25° is denoted as Ia, the integrated intensity of a diffraction peak of the (003) plane at a diffraction angle 2&thetas; of around 43.5° is denoted as Ib, and the integrated intensity of a diffraction peak of the (-601) plane, the diffraction peak existing at a 2&thetas; of around 44.5°, is denoted as Ic, Ib/Ia is in the range of 0.35-0.65, and Ic/Ib is in the range of 0.85-1.50. |
