| 摘要 |
The present invention provides a
process for producing a lithium secondary battery which employs charging method where a positive electrode upon charging has a maximum achieved potential of 4.3V (vs. Li/Li + ) or lower, comprising:
charging the lithium secondary battery to reach at least a region with relatively flat fluctuation of potential appearing in a positive electrode potential region exceeding 4.3V (vs. Li/Li + ) and 4.8V (vs. Li/Li + ) or lower,
wherein the lithium secondary battery includes an active material comprising a solid solution of a lithium transition metal composite oxide having an ±-NaFeO 2 type crystal structure;
wherein the composition ratio of Li, Co, Ni, and Mn contained in the solid solution satisfies Li 1+1/3x Co 1-x-y Ni y/2 Mn 2x/3+y/2 with x + y ‰¤ 1, 0 ‰¤ y and 1 - x - y = z; and
wherein, in an Li[Li 1/3 Mn 2/3 ]O 2 (x)-LiNi 1/2 Mn 1/2 O 2 (y)-LiCoO 2 (z) type ternary phase diagram, (x, y, z) is represented by values in a range present on or within a line of a heptagon (ABCDEFG) defined by the vertexes; point A(0.45,0.55,0), point B(0.63,0.37,0), point C(0.7,0.25,0.05), point D(0.67,0.18,0.15), point E(0.75,0,0.25), point F(0.55,0, 0.45), and point G(0.45,0.2,0.35). |
