Nonaqueous electrolyte battery
A nonaqueous electrolyte battery includes: a positive electrode, a negative electrode, and a nonaqueous electrolyte, wherein the positive electrode contains, as a positive electrode active material, a positive electrode material having a surface composition represented by the following formula (I); the nonaqueous electrolyte contains a halogenated carbonate represented by any of the following formulae (1) to (2) and an alkylbenzene represented by the following formula (3); a content of the halogenated carbonate is 0.1% by mass or more and not more than 50% by mass relative to the nonaqueous electrolyte; and a content of the alkylbenzene is 0.1% by mass or more and not more than 5% by mass relative to the nonaqueous electrolyte
1. A nonaqueous electrolyte battery comprising:
a positive electrode,
a negative electrode, and
a nonaqueous electrolyte, wherein
the positive electrode contains, as a positive electrode active material, a positive electrode material having a surface composition represented by the following formula (I);
the nonaqueous electrolyte contains a halogenated carbonate represented by any of the following formulae (1) to (2) and an alkylbenzene, wherein the alkylbenzene is one or more of tert-pentylbenzene, 1,2-diethylpropylbenzene and 2,2-diphenylpropane;
a content of the halogenated carbonate is 0.1% by mass or more and not more than 50% by mass relative to the nonaqueous electrolyte; and
a content of the alkylbenzene is 0.1% by mass or more and not more than 5% by mass relative to the nonaqueous electrolyte
Li p Ni (1-q-r) M1 q M2 r O (2-y) X z (I)
wherein
each of M1 and M2 represents at least one member selected from the group consisting of elements of the groups 2 to 15 other than nickel (Ni); X represents at least one member selected from the group consisting of elements of the groups 16 and 17 other than oxygen (O); p, q, r, y and z are values falling within the ranges of (0≤p≤1.5), (0≤q≤1.0), (0≤r≤1.0), (−0.10≤y≤0.20) and (0≤z≤0.2), respectively; and (q+r) is less than 1,
wherein
each of R21 to R26 independently represents a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, provided that at least one of R21 to R26 is a halogen group or a halogenated alkyl group,
wherein
each of R27 to R30 independently represents a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, provided that at least one of R27 to R30 is a halogen group or a halogenated alkyl group.
2. The nonaqueous electrolyte battery according to claim 1 , wherein
the positive electrode material has a surface composition with a high nickel content, represented by the formula (I) wherein (q+r) is not more than 0.5.
3. The nonaqueous electrolyte battery according to claim 1 , wherein
a mass ratio of the halogenated ester to the alkylbenzene (halogenated ester/alkylbenzene) is 0.1 or more and not more than 200.
4. The nonaqueous electrolyte battery according to claim 1 , wherein
the halogenated carbonate is at least one member selected from the group consisting of fluoromethyl methyl carbonate, bis(fluoromethyl) carbonate, 4-fluoro-1,3-dioxolan-2-one and 4,5-difluoro-1,3-dioxolan-2-one.
5. The nonaqueous electrolyte battery according to claim 1 , wherein
the positive electrode material is a lithium nickel complex oxide having the composition represented by the formula (I).
6. The nonaqueous electrolyte battery according to claim 5 , wherein
the lithium nickel complex oxide is a lithium nickel complex oxide with a high nickel content, represented by the formula (I) wherein (q+r) is not more than 0.5.
7. The nonaqueous electrolyte battery according to claim 6 , wherein
the positive electrode contains, as the positive electrode active material, other lithium complex oxide, in addition to the lithium nickel complex oxide with a high nickel content, and
a content of the lithium nickel complex oxide with a high nickel content is 50% by mass or more relative to a total mass of the positive electrode active material.
8. The nonaqueous electrolyte battery according to claim 7 , wherein
the other lithium complex oxide is at least one member selected from the group consisting of lithium cobaltate; a cobalt based lithium complex oxide containing a metal element other than cobalt disposed in place of at least a part of cobalt in lithium cobaltate; and a lithium manganese complex oxide having a spinel type structure.
9. The nonaqueous electrolyte battery according to claim 1 , wherein
the positive electrode material has
a lithium complex oxide particle, and
a coating layer provided in at least a part of the surface of the lithium complex oxide particle; and
the coating layer contains an oxide having lithium, nickel and manganese.
10. The nonaqueous electrolyte battery according to claim 9 , wherein
a composition ratio of nickel to manganese in the coating layer falls within the range of 95/5 to 20/80.
11. The nonaqueous electrolyte battery according to claim 9 , wherein
an amount of the coating layer is 2% by mass or more and not more than 30% by mass relative to the lithium complex oxide particle.