Method of producing negative electrode, negative electrode, and lithium-ion secondary battery
AssigneeToyota Jidosha Kabushiki Kaisha
InventorAtsushi Sugihara
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Abstract
A method of producing a negative electrode includes at least the following (A) to (C): (A) mixing powder consisting of lithium titanate oxide particles, a binder, and a solvent to prepare a particle-dispersed liquid; (B) granulating powder consisting of graphite-based particles by using the particle-dispersed liquid to prepare wet granules; and (C) forming the wet granules into a negative electrode composite material layer to produce a negative electrode. The negative electrode composite material layer is formed so as to include the lithium titanate oxide particles in an amount not lower than 2 mass % and not higher than 15 mass % of the total amount of the graphite-based particles and the lithium titanate oxide particles.
Claims10
A negative electrode of a lithium-ion secondary battery, the negative electrode comprising:
- at least a negative electrode composite material layer,
- the negative electrode composite material layer including graphite-based particles, lithium titanate oxide particles, and a binder,
- the negative electrode composite material layer including the lithium titanate oxide particles in an amount not lower than 3 mass % and not higher than 5 mass % of a total amount of the graphite-based particles and the lithium titanate oxide particles,
- a ratio of a D50 of the graphite-based particles to a D50 of the lithium titanate oxide particles is not lower than 20 and not higher than 250,
- the graphite-based particles are linked to each other via linking portions consisting of the lithium titanate oxide particles and binder with no direct contact between graphite-based particles and an amount of an electric current flowing across an interface between adjacent ones of the graphite-based particles measured in a cross section of the negative electrode composite material layer with a scanning probe microscope is not lower than 13 nA and not higher than 75 nA.
A negative electrode prepared by a process comprising:
- mixing a powder consisting of lithium titanate oxide particles, a binder, and a solvent to prepare a particle-dispersed liquid;
- after mixing the lithium titanate oxide particles, binder, and solvent to prepare the particle-dispersed liquid, granulating a powder consisting of graphite-based particles by using the particle-dispersed liquid to prepare wet granules;
- and
- forming the wet granules into a negative electrode composite material layer;
- and
- placing the negative electrode composite material layer on a surface of a negative electrode current collector to produce the negative electrode comprising the negative electrode composite material layer disposed on the negative electrode current collector,
- wherein:
- the negative electrode composite material layer includes the lithium titanate oxide particles in an amount not lower than 3 mass % and not higher than 5 mass % of a total amount of the graphite-based particles and the lithium titanate oxide particles;
- a ratio of a D50 of the graphite-based particles to a D50 of the lithium titanate oxide particles is not lower than 20 and not higher than 250;
- the graphite-based particles are linked to each other via linking portions consisting of the lithium titanate oxide particles and the binder with no direct contact between graphite based particles;
- and
- an amount of an electric current flowing across an interface between adjacent ones of the graphite-based particles measured in a cross section of the negative electrode composite material layer with a scanning probe microscope is not lower than 13 nA and not higher than 75 nA.
Dependencies are inferred from the claim text.