Nonaqueous electrolyte battery
According to one embodiment, there is provided a nonaqueous electrolyte battery. The nonaqueous electrolyte battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a positive current collector and a positive electrode material layer formed on the positive electrode current collector. The positive electrode material layer includes a positive electrode active material and a first conductive agent. In a mapping image for the positive electrode material layer, a ratio of an occupancy area of the first conductive agent to an occupancy area of the positive electrode active material is from 1.5 to 5.
1. A nonaqueous electrolyte battery comprising:
a positive electrode comprising a positive electrode current collector and a positive electrode material layer formed on the positive electrode current collector, the positive electrode material layer comprising a positive electrode active material in an amount of 75-96% by mass based on the positive electrode material layer and a first conductive agent, the first conductive agent comprising a D-band appearing at 1350±10 cm −1 and a G-band appearing at 1590±10 cm −1 in a Raman chart obtained according to Raman spectroscopy, a ratio of an integrated intensity of the D-band to an integrated intensity of the G-band being more than 0.6 and not more than 10, and a ratio of an occupancy area of the first conductive agent to an occupancy area of the positive electrode active material being from 1.5 to 5 in a mapping image obtained according to Raman spectroscopy for the positive electrode material layer;
a negative electrode; and
a nonaqueous electrolyte.
2. The nonaqueous electrolyte battery according to claim 1 ,
wherein, in the mapping image, a ratio of a distance of particles of the positive electrode active material to a distance between particles of the first conductive agent is from 0.9 to 1.1.
3. The nonaqueous electrolyte battery according to claim 1 ,
wherein the ratio of the occupancy area of the first conductive agent to the occupancy area of the positive electrode active material is from 1.7 to 3.5.
4. The nonaqueous electrolyte battery according to claim 1 ,
wherein the first conductive agent comprises at least one selected from the group consisting of carbon black, activated carbon, and carbon fiber.
5. The nonaqueous electrolyte battery according to claim 1 ,
wherein the positive electrode material layer further comprises a second conductive agent; and
the second conductive agent comprises a D-band appearing at 1350±10 cm −1 and a G-band appearing at 1590±10 cm −1 in a Raman chart obtained according to Raman spectroscopy and a ratio of an integrated intensity of the D-band to an integrated intensity of the G-band is more than 0 and not more than 0.6.
6. The nonaqueous electrolyte battery according to claim 5 ,
wherein the second conductive agent comprises at least one selected from the group consisting of graphite and graphene.
7. The nonaqueous electrolyte battery according to claim 1 ,
wherein the positive electrode active material comprises Li y Ni 1-c-d Co c Mn d M e O 2 , wherein 0.9<y≦1.25, 0<c≦0.3, 0<d≦0.45, and 0≦e≦0.1, and M is at least one element selected from the group consisting of Mg, Al, Si, Ti, Zn, Zr, Ca, and Sn.
8. The nonaqueous electrolyte battery according to claim 1 ,
wherein the positive electrode material layer further comprises a binder.
9. The nonaqueous electrolyte battery according to claim 8 ,
wherein the binder comprises at least one selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride, modified polyvinylidene fluoride, copolymers of vinylidene fluoride-hexafluoropropylene, and terpolymers of polyvinylidene fluoride-tetrafluoroethylene-hexafluoropropylene.
10. The nonaqueous electrolyte battery according to claim 1 ,
wherein the negative electrode comprises a negative electrode current collector and a negative electrode material layer formed on the negative electrode current collector; and
the negative electrode material layer comprises a negative electrode active material.
11. The nonaqueous electrolyte battery according to claim 10 ,
wherein the negative electrode active material comprises at least one selected from the group consisting of metals, metal alloys, metal oxides, metal sulfides, metal nitrides, graphitized materials, and carbonaceous materials.
12. The nonaqueous electrolyte battery according to claim 10 ,
wherein the negative electrode active material comprises lithium titanate.
13. The nonaqueous electrolyte battery according to claim 3 ,
wherein, in the mapping image, a ratio of a distance of particles of the positive electrode active material to a distance between particles of the first conductive agent is from 0.9 to 1.1.