Positive electrode material, non-aqueous electrolyte secondary battery, and method of producing positive electrode material
A positive electrode material consists of composite particles. Each of the composite particles includes a base material particle, a film, and a carbon nanotube. The film covers at least a part of a surface of the base material particle. The base material particle includes a positive electrode active material. The film includes a boron oxide. The carbon nanotube includes a first portion and a second portion. The first portion is buried in the film. The second portion is exposed on a surface of the film.
1. A non-aqueous electrolyte secondary battery comprising a positive electrode material,
the positive electrode material consisting of composite particles,
each of the composite particles including a base material particle, a film, and a carbon nanotube,
the film covering at least a part of a surface of the base material particle,
the base material particle including a positive electrode active material, the positive electrode active material comprising LiMeO 2 , Me denotes one or more metallic elements,
the film including a boron oxide,
the carbon nanotube including a first portion and a second portion,
the first portion being buried in the film,
the second portion being exposed on a surface of the film,
wherein a percentage of an amount of substance of boron to a total amount of substance of metal elements other than lithium contained in the positive electrode active material and boron measured by x-ray photoelectron spectroscopy is 80% or higher,
wherein a percentage of a mass of the carbon nanotube to a mass of the positive electrode active material is from 0.02% to 0.06%,
wherein a capacity retention of the non-aqueous electrolyte secondary battery is greater than or equal to 97.3%, wherein the capacity retention is a percentage of a 100 th cycle discharged capacity to a 1 st cycle discharged capacity, and
wherein a battery resistance of the non-aqueous electrolyte secondary battery is less than or equal to 42.7 mΩ.
2. The non-aqueous electrolyte secondary battery of claim 1 , wherein a diameter of the base material particle is from 1 μm to 30 μm.
3. The non-aqueous electrolyte secondary battery of claim 1 , wherein the boron oxide comprises Li.
4. The non-aqueous electrolyte secondary battery of claim 1 , wherein the boron oxide is amorphous.
5. The non-aqueous electrolyte secondary battery of claim 1 , wherein the positive electrode active material comprises LiNi 0.8 C 00.1 Mn 0.1 O 2 .
6. The non-aqueous electrolyte secondary battery of claim 1 , wherein the capacity retention of the non-aqueous electrolyte secondary battery is from 97.3% to 98.0%.
7. The non-aqueous electrolyte secondary battery of claim 1 , wherein the battery resistance of the non-aqueous electrolyte secondary battery is from 42.2 mΩ to 42.7 mΩ.
8. The non-aqueous electrolyte secondary battery of claim 1 , wherein the positive electrode active material comprises LiNi a Co b Mn c O 2 , wherein 0.7<a<1, 0<b<0.3, 0<c<0.3, and a+b+c=1.
9. A method of producing a non-aqueous electrolyte secondary battery comprising a positive electrode material, comprising:
mixing a base material particle, boric acid, a carbon nanotube, and a solvent to prepare a first precursor;
drying the first precursor to prepare a second precursor; and
heating the second precursor to prepare a composite particle,
the non-aqueous electrolyte secondary battery comprising the positive electrode material consisting of the composite particles,
each of the composite particles including the base material particle, a film, and the carbon nanotube,
the film covering at least a part of a surface of the base material particle,
the base material particle including a positive electrode active material, the positive electrode active material comprising LiMeO 2 , Me denotes one or more metallic elements,
the film including a boron oxide,
the film being formed in such a way that the carbon nanotube includes a first portion and a second portion,
the first portion being buried in the film,
the second portion being exposed on a surface of the film,
wherein a percentage of an amount of substance of boron to a total amount of substance of metal elements other than lithium contained in the positive electrode active material and boron measured by x-ray photoelectron spectroscopy is 80% or higher,
wherein a percentage of a mass of the carbon nanotube to a mass of the positive electrode active material is from 0.02% to 0.06%,
wherein a capacity retention of the non-aqueous electrolyte secondary battery is greater than or equal to 97.3%, wherein the capacity retention is a percentage of a 100 th cycle discharged capacity to a 1 st cycle discharged capacity, and
wherein a battery resistance of the non-aqueous electrolyte secondary battery is less than or equal to 42.7 mΩ.