| 摘要 |
The positive electrode of a lithium ion secondary battery contains active material particles represented by the following formula: Li<SUB>x</SUB>Ni<SUB>1-y</SUB>M<SUB>y</SUB>Me<SUB>z</SUB>O<SUB>2+d</SUB>, and the active material particles contain a lithium complex oxide represented by the following formula: Li<SUB>x</SUB>Ni<SUB>1-y</SUB>M<SUB>y</SUB>O<SUB>2</SUB> (in this connection, 0.95 = x = 1.1, 0 < y = 0.75 and 0.001 = z = 0.05). The element M is selected from the group consisting of alkaline earth elements, transition elements, rare earth elements, group IIIb elements and group IVb elements. The element Me is selected from the group consisting of Mn, W, Nb, Ta, In, Mo, Zr and Sn, and this element Me is contained in the surface layers of the active material particles. When a constant current discharge is performed at 25°C, at a current value of 1C to a final voltage of 2.5V, the lithium content x of the lithium complex oxide in the charging end state satisfies the following relation: 0.85 = x = -0.013Ln(z) + 0.871. |
