| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium cobalt compound oxide powder for a positive electrode of a lithium secondary battery which is large in volume capacity density, high in safety, and superior in any of charge and discharge cycle durability (capacity maintenance rate), and provide its evaluation method. <P>SOLUTION: As for the positive electrode active material for the lithium secondary battery composed of the lithium cobalt compound oxide powder expressed by a general formula Li<SB>p</SB>Co<SB>x</SB>M<SB>y</SB>O<SB>z</SB>F<SB>a</SB>(M is a transition metal element other than Co or an alkaline earth metal element. 0.9≤p≤1.1, 0.980≤x≤1.000, 0≤y≤0.02, 1.9≤z≤2.1, 1.9≤z≤2.1, x+y=1, 0≤a≤0.02), respective spectrum absorption strength in the vicinity of 1,450 cm<SP>-1</SP>and the vicinity of 1,030 cm<SP>-1</SP>in a diffusion reflection type Fourier transform infrared ray spectrometer is detected, and evaluation is made based on whether the spectrum absorption strength ratio is within a prescribed range or not. In particular, by making the spectrum absorption strength ratio of the respective spectrums of 1,450 cm<SP>-1</SP>and 1,030 cm<SP>-1</SP>0.2 or less, the lithium cobalt compound oxide powder of superior characteristics can be obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
