Lithium ion secondary battery and electrolyte thereof

A technology for secondary batteries and electrolytes, applied in secondary batteries, circuits, electrical components, etc., can solve the problems that the thickness expansion improvement effect is not too obvious and the effect is not ideal, and achieves excellent high-temperature storage performance and excellent cycle performance. , the effect of preventing decomposition

Inactive Publication Date: 2012-07-11
DONGGUAN AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the above problems, the Chinese patent application No. 200910133674.8 proposes to use tripolyfluorophosphazene as an additive to

Method used

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  • Lithium ion secondary battery and electrolyte thereof
  • Lithium ion secondary battery and electrolyte thereof
  • Lithium ion secondary battery and electrolyte thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Preparation of cathode sheet:

[0036] The positive electrode active material lithium cobaltate (LiCoO 2 ), conductive carbon (Super-P) and polyvinylidene fluoride (PVDF) are mixed in the solvent according to the mass ratio of 95:2:3, and stirred evenly to obtain the cathode slurry. The slurry is coated on a 9 μm aluminum foil, dried, and cold pressed to obtain a compacted density of 1.6 g / cm 3 The pole piece is then cut and welded to obtain the cathode piece.

[0037] Preparation of anode sheet:

[0038] The negative electrode active material natural graphite, conductive carbon (Super-P) and sodium carboxymethylcellulose (CMC) were mixed in the solvent according to the mass ratio of 95:2:3, and stirred evenly to obtain the anode slurry. Coat the slurry on a 9μm copper foil, dry, and cold press to obtain a compacted density of 1.7g / cm 3 The pole piece is cut and welded to obtain the anode piece.

[0039] The separator adopts a polypropylene (PP) porous membrane wit...

Embodiment 2

[0045] Different from Example 1, the positive electrode active material is lithium nickel cobalt manganese oxide (LiNi 0.4 co 0.3 mn 0.3 o 2 ) and lithium nickelate (LiNiO 2 ), the mass ratio of the two is 1:1; the negative electrode active material is a mixture of hard carbon and soft carbon, and the mass ratio of the two is 3:1; the separator adopts a polyethylene (PE) porous film with a thickness of 16 μm.

[0046] The electrolyte was prepared as follows:

[0047] Mix the non-aqueous solvent butylene carbonate, dimethyl carbonate, ethyl formate and fluorobenzene in a mass ratio of 3:1:0.1:0.2, let stand for 30 minutes, and then add 2% and 3% of 1 by mass, 3-propane sultone and vinylene carbonate, then lithium salts (lithium difluorooxalate borate (LiDFOB) and LiBF 4 The mixture of the two, the mass ratio of the two is 4:1), so that it is fully dissolved, and the concentration of the lithium salt is 0.85M. Finally add 2,4,6-trifluoro-2-(3-trifluoromethylphenoxy)-6-etho...

Embodiment 3

[0050] The difference from Example 1 is that the positive active material is lithium iron phosphate (LiFePO 4 ) and lithium vanadium phosphate (LiVPO 4 ), the mass ratio of the two is 6:1; the negative electrode active material is simple silicon; the separator adopts a PP / PE / PP composite film with a thickness of 20 μm.

[0051] The electrolyte was prepared as follows:

[0052] The non-aqueous solvent propylene carbonate, ethyl methyl carbonate, 3,3-difluoropropionate methyl ester and tetrahydrofuran were mixed uniformly in a mass ratio of 2:10:0.5:0.5, allowed to stand for 30 minutes, and then added with a mass percentage of 4% and 5% 1,3-propane sultone and fluoroethylene carbonate, and then add lithium salt LiBOB to fully dissolve it, and make the concentration of lithium salt 1.3M. Finally, add 2,4,6-trifluoro-2-(3-trifluoromethylphenoxy)-4-chloro-6-methoxy-cyclotriphosphazene to make its mass percentage in the electrolyte The content is 20%, and the mixture is uniform, ...

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Abstract

The invention, belonging to the technical field of lithium ion secondary battery, particularly relates to an electrolyte for a lithium ion secondary battery, comprising a non-aqueous solvent, lithium salts and additives, wherein the additives comprise a fluorinated cyclotriphosphazene derivative of formula (I), R1 represents aromatic group or aromatic group containing halogen substituent group, R2 represents alkyl, alkylene or halogen substituted alkyl, alkylene, R3 represents hydrogen, halogen, alkyl or alkyloxy, halogenated alkyl groups or halogenated alkyloxy, and the fluorinated cyclotriphosphazene derivative accounts for 0.1-20 wt% of the total weight of the electrolyte. Compared with the prior art, by using the fire resistance function of fluorinated cyclotriphosphazene derivative, the decomposition of the electrolyte on the anode surface can be effectively prevented, the decomposition and gas generation of the electrolyte are reduced, and the high temperature storage thickness expansion ratio of the battery is greatly reduced. In addition, the invention further discloses a lithium ion secondary battery containing the electrolyte.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion secondary batteries, and in particular relates to an electrolyte that can significantly improve the high-temperature storage performance of the lithium-ion secondary battery and has excellent thermal stability, and a lithium-ion battery containing the electrolyte. Background technique [0002] Lithium-ion secondary batteries can be said to be the most advanced commercial secondary batteries in the world at present. With the development of various electronic products, the market demand for lithium-ion secondary batteries as energy supply components of these electronic products is showing rapid growth trend. Moreover, because lithium-ion secondary batteries have many advantages such as high discharge voltage, high energy density, and excellent low self-discharge characteristics, they have been applied in more and more fields, such as power vehicles, electric bicycles, and energy storage power st...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/0525
CPCY02E60/122Y02E60/10
Inventor 莫明亮钟松材陈杰吴凯
Owner DONGGUAN AMPEREX TECH
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