| 摘要 |
A transition metal oxide containing solid-solution lithium that realizes high initial discharge capacity and capacity retention is represented by the compositional formula: Li1.5[NiaMbMnc[Li]d]O3, wherein M represents at least one kind of element selected from the group consisting of silicon, phosphorus and metal elements (excluding Ni, Mn and Li), a, b, c and d satisfy specific relationships, and n is the valence of M. The oxide has a layered structure site and a site which changes to a spinel structure by performing a charge or a charge-discharge in a predetermined electric potential range, and a spinel structure change ratio k in a range of 0.25≦k<1.0 when the spinel structure change ratio is assumed to be 1 in a case where Li2MnO3 of the layered structure in the transition metal oxide containing solid-solution lithium completely changes to LiMn2O4 of the spinel structure. |
| 主权项 |
1. A non-aqueous electrolyte secondary battery using a transition metal oxide containing solid-solution lithium as a positive electrode, wherein
the transition metal oxide containing solid-solution lithium is represented by the compositional formula (1):
Li1.5[NiaMbMnc[Li]d]O3 (1) wherein Li represents lithium, Ni represents nickel, M represents at least one kind of element selected from the group consisting of silicon, phosphorus and metal elements (but excluding Ni, Mn and Li), Mn represents manganese, O represents oxygen, a, b, c and d satisfy the relationships of 0<a<1.4, 0<b≦0.2, 0<c<1.4, 0.1<d≦0.4, a+b+c+d=1.5 and 1.1≦[a+b+c]<1.4, and n, which is the valence of M, is in a range of 3.5≦n≦6 (when M consists of two or more elements, n is the average value of the valence of each element), wherein the transition metal oxide containing solid-solution lithium has a layered structure site and a site which changes to a spinel structure by performing a charge or a charge-discharge in a predetermined electric potential range, and a spinel structure change ratio k of the transition metal oxide containing solid-solution lithium is in a range of 0.25≦k<1.0 when the spinel structure change ratio is assumed to be 1 in a case where Li2MnO3 of the layered structure in the transition metal oxide containing solid-solution lithium completely changes to LiMn2O4 of the spinel structure, and a predetermined spinel structure change ratio k of the transition metal oxide containing solid-solution lithium is obtained by electrochemical pretreatment of preforming a charge or a charge-discharge in which the maximum potential of the battery in a predetermined electric potential range is 4.3 V or higher and less than 4.8 V as a conversion to a lithium metal counter electrode, and charge-discharge treatment of performing a charge or a charge-discharge in which the maximum potential of the battery in a predetermined electric potential range is 4.8 V as a conversion to the lithium metal counter electrode. |
