# US 8,785,050 B2 · Lithium ion secondary battery

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- Number: US 8,785,050 B2
- Document ID: US8785050B2
- Status: Granted
- Kind: B2
- Application number: 13/813,458
- Filed: 2010-08-05
- Published: 2013-05-23
- Granted: 2014-07-22
- Earliest claimed: 2010-08-05
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Takeshi Abe; Yohei Shindo; Akira Tsujiko; Machiko Abe; Keiko Wasada
- Inventors: Takeshi Abe; Yohei Shindo; Akira Tsujiko; Machiko Abe; Keiko Wasada
- Web page: https://patentgrep.com/patent/US8785050B2

## CPC

- C01B 32/20: Graphite
- C01B 32/205: Preparation
- H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines}
- H01M 4/583: Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/587: for inserting or intercalating light metals
- C01P 2002/82: by IR- or Raman-data
- C01P 2006/40: Electric properties
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- Y02E 60/10: Energy storage using batteries
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Provided is a lithium-ion secondary battery having an excellent initial capacity as well as a good capacity retention rate. The battery comprises a positive electrode comprising a positive electrode active material, a negative electrode comprising a negative electrode active material, and a non-aqueous liquid electrolyte. The negative electrode active material comprises a graphitic material that satisfies each of the following properties: (a) in its Raman spectrum obtained by Raman scattering analysis using an exciting light at a wavelength of 532 nm, having a ratio of its D-peak intensity ID to its G-peak intensity IG, an R value (ID/IG), of 0.15 or smaller; and (b) having a full width at half maximum of the G peak, ΔvG, of 23 cm−1 or smaller. The secondary battery has a capacity retention rate of 70% or greater when subjected to 500 cycles of charging and discharging at a constant current rate of 2 C at 60° C.

## Claims

### Claim 1

A lithium-ion secondary battery comprising:
a positive electrode comprising a positive electrode active material;
a negative electrode comprising a negative electrode active material; and
a non-aqueous liquid electrolyte, and
wherein the negative electrode active material comprises as its primary component a graphitic material that satisfies each of the following properties:
(a) in its Raman spectrum obtained by Raman scattering analysis using an exciting light at a wavelength of 532 nm, having a ratio of its D-peak intensity ID to its G-peak intensity IG, an R value (ID/IG), of 0.15 or smaller; and
(b) having a full width at half maximum of the G peak, ΔvG, of 23 cm−1 or smaller; and
the lithium-ion secondary battery shows a capacity retention rate of 70% or greater when subjected at to 500 cycles of charging and discharging at a constant current rate of 2 C at 60° C., and
the positive electrode comprises an olivine lithium-containing compound.

### Claim 2 (depends on 1)

The lithium-ion secondary battery according to claim 1, wherein the graphitic material satisfies the R value of 0.05 or greater and 0.10 or smaller and the ΔvG value of 0.15 cm−1 or greater and 20 cm−1 or smaller.

### Claim 3 (depends on 1)

The lithium-ion secondary battery according to claim 1, wherein the graphitic material further satisfies the following property:
(c) having an initial capacity of 300 mAh/g or higher.

### Claim 4 (depends on 1)

The lithium-ion secondary battery according to claim 1, wherein the negative electrode active material consists of the graphitic material and the positive electrode active material consists of the olivine lithium-containing compound.

### Claim 5 (depends on 1)

The lithium-ion secondary battery according to claim 1 that is used as a vehicle-driving power source.

### Claim 6 (depends on 4)

The lithium-ion secondary battery according to claim 4, wherein the graphitic material satisfies the R value of 0.06 or greater and 0.08 or smaller and the ΔvG value of 0.18 cm−1 or greater and 20 cm−1 or smaller.

### Claim 7 (depends on 1)

The lithium-ion secondary battery according to claim 1, wherein the graphitic material is a synthetic graphite obtainable by graphitization of a petroleum coke, and
the synthetic graphite is one graphitized by, under a non-oxidative atmosphere, calcining at 1200° C. to 1500° C. for 2 to 3 hours, and then baking at above 2200° C. but below 3000° C. for 1 to 6 hours.