Lithium ion secondary battery containing a negative electrode material layer containing Si and O as constituent elements

• US 9,673,446 B2
• Filed: 02/28/2012
• Issued: 06/06/2017
• Est. Priority Date: 02/28/2012
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi Maxell Limited (Hitachi, Ltd.)
• Inventors: Kojima, Eri, Furutani, Takahiro, Kishimi, Mitsuhiro
• Primary Examiner(s): DOUYETTE, KENNETH J
• Application Number:
  US13/701,118
• Publication Number:
  US 20130224575A1
• Time in Patent Office: 1,925 Days
• Field of Search: 4292311, 429144, 429223, 429224, 429199, 4292181, 429188, 4292318
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A lithium ion secondary battery containing a negative electrode active material containing Si and O as constituent elements and exhibiting excellent charge-discharge cycle characteristics. The lithium ion secondary battery has a positive electrode having a positive electrode material mixture layer, a negative electrode, a separator and a nonaqueous electrolyte containing at least an electrolyte salt and an organic solvent, where the negative electrode has a negative electrode material mixture layer containing a negative electrode active material containing Si and O as constituent elements (the atomic ratio x of O to Si is 0.5≦x≦1.5). The nonaqueous electrolyte contains the electrolyte salt at a concentration exceeding a concentration at which conductivity in the nonaqueous electrolyte containing the electrolyte salt and the organic solvent is maximized, and the conductivity at 25° C. is 6.5 to 16 mS/cm.

Claims

1. A lithium ion secondary battery comprising a positive electrode having a positive electrode material mixture layer, a negative electrode, a separator and a nonaqueous electrolyte containing at least an electrolyte salt and an organic solvent,

wherein the negative electrode has a negative electrode material mixture layer that comprises as a negative electrode active material a composite of a material containing Si and O as constituent elements and a carbon material,

wherein an atomic ratio x of O to Si is 0.5≦

x≦

1.5,

the nonaqueous electrolyte contains the electrolyte salt at a concentration of higher than 1.2 mol/L and has a conductivity at 25°

C. of 6.5 to 12.2 mS/cm,

a relationship of A/B≧

4 is satisfied when A (mA) indicates a current value for discharging a capacity of the lithium ion secondary battery in an hour and B (cm²) indicates an opposed area between the positive electrode material mixture layer and the negative electrode material mixture layer, and

the nonaqueous electrolyte further contains 4-fluoro-1,3-dioxolan-2-one as halogen-substituted cyclic carbonate, and at least one selected from dimethyl carbonate and diethyl carbonate as chain carbonate.

2. The lithium ion secondary battery according to claim 1, wherein the nonaqueous electrolyte contains the electrolyte salt at a concentration of 1.4 mol/L or higher and lower than 30 mol/L.

3. The lithium ion secondary battery according to claim 1, wherein the electrolyte salt in the nonaqueous electrolyte is LiPF₆, LiBF₄ or an imide salt.

4. The lithium ion secondary battery according to claim 1, containing further graphite as a negative electrode active material.