| 摘要 |
PROBLEM TO BE SOLVED: To provide an active material for a nonaqueous electrolyte secondary battery having a large discharge capacity and a superior high-rate discharge performance.SOLUTION: An active material for a nonaqueous electrolyte secondary battery contains: a lithium transition metal complex oxide having α-NaFeOtype crystal structure, and expressed by the composition formula, LiMeO(where Me is a transition metal element including Co, Ni and Mn; α>0), of which the composition ratio Li/Me of lithium Li to a transition metal element Me is 1.6 or less, and the mole ratio Mn/Me of Mn to the transition metal element Me is 0.63-0.72. As to the lithium transition metal complex oxide, an oxygen position parameter determined from crystal structure analysis according to Rietveld method in the case of using R3-m for a crystal structure model based on an X-ray diffraction pattern in a state at the end of discharge is 0.260 or less. The lithium transition metal complex oxide is observed as a single phase belonging to the space group, R3-m on an X-ray diffraction diagram when being electrochemically oxidized to a potential of 5.0 V(vs. Li/Li).SELECTED DRAWING: Figure 1 |
