Electrode active material for lithium ion secondary battery, electrode for lithium ion secondary battery, lithium ion secondary battery using the same, and method for producing electrode active material for lithium ion secondary battery

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 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 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 of around 25° is denoted as Ia, the integrated intensity of a diffraction peak of the (003) plane at a diffraction angle 2 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 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.