In-situ cross-linked polymer binding agent for lithium ion battery and electrode prepared from same

A lithium-ion battery, in-situ cross-linking technology, applied in battery electrodes, non-aqueous electrolyte battery electrodes, secondary batteries, etc., can solve the problems of irreversible slippage between active material particles and polymer binders, irreversible capacity increase, etc. , to achieve the effect of non-toxic and non-polluting source, conducive to dispersion uniformity and maintaining stability

Active Publication Date: 2016-11-23
GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these polymers are polymers with a linear chain structure, and long-term cycling will cause irreversible slippage between the active material particles and the polymer binder, resulting in an increase in the irreversible capacity.

Method used

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  • In-situ cross-linked polymer binding agent for lithium ion battery and electrode prepared from same
  • In-situ cross-linked polymer binding agent for lithium ion battery and electrode prepared from same
  • In-situ cross-linked polymer binding agent for lithium ion battery and electrode prepared from same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Sodium alginate (Alg) with a medium viscosity, a molecular weight of 800,000-1,200,000 g / mol, and a monomer ratio of glucuronic acid (M) to guluronic acid (G) of about 1.56 is prepared into a 2% aqueous solution ; The water-soluble chitosan (Chisotan) with a carboxylation degree greater than or equal to 60% is formulated into a 5% aqueous solution. Take 1.2g of spherical silicon particles with a particle size distribution of 50-150nm and 0.5g of conductive carbon black (Super-P) into 6.5g of sodium alginate aqueous solution and mix well, add 3g of chitosan solution, and then add 0.03g Oxalic acid powder, and add 6.5g of pure water, adjust the solid content of the slurry to 11.6% and mix evenly. The obtained slurry is uniformly coated on the copper current collector, and the loading amount of the active silicon material is controlled at 1.5 mg / cm 2 ; After air-drying at room temperature, roll it with a roller machine, and control the compaction density to 0.7mg / cm 3 . ...

Embodiment 2

[0039] The polyacrylic acid with a molecular weight of 100000g / mol is prepared into a 5% aqueous solution; the water-soluble chitosan with a carboxylation degree greater than or equal to 60% is prepared into a 5% aqueous solution. Get 1.2g of spherical silicon particles with a particle size distribution of 50-150nm and 0.5g of conductive carbon black (Super-P) into a mixed solution of 3g of water-soluble chitosan and 2.4g of polyacrylic acid, then add 0.0328g of lemon monohydrate acid, and add 10g of pure water to adjust the solid content of the slurry to 11.6% and mix well. The obtained slurry is uniformly coated on the copper current collector, and the loading amount of the active silicon material is controlled at 1.5 mg / cm 2 ; After air-drying at room temperature, roll it with a roller machine, and control the compaction density to 0.7mg / cm 3 . The obtained electrode ratio is: active silicon material:conductive additive:polymer binder=60:25:15. Wherein the mass fraction ...

Embodiment 3

[0044] Take 2g of sodium alginate powder with a medium viscosity, a molecular weight of 800,000-1,200,000g / mol, and a monomer ratio of glucuronic acid (M) to guluronic acid (G) of about 1.56, and add it to 98g of pure water Prepare 2% aqueous solution, add 0.02g anhydrous CaCl 2 Formulated into sodium alginate hydrogel (Alg hydrogel). The water-soluble chitosan whose carboxylation degree is greater than or equal to 60% is formulated into a 5% aqueous solution. Take 1.2g of spherical silicon particles with a particle size distribution of 50-150nm and 0.5g of conductive carbon black (Super-P) into a mixed solution of 7.0g of sodium alginate hydrogel and 3g of chitosan, and then add 0.01g of Phthalic acid powder, and 5.5g of pure water was added to adjust the solid content of the slurry to 11.6% and mixed evenly. The obtained slurry is uniformly coated on the copper current collector, and the loading amount of the active silicon material is controlled at 1.5 mg / cm 2 ; After ai...

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Abstract

The invention discloses an in-situ cross-linked polymer binding agent for a lithium ion battery and an electrode prepared from the in-situ cross-linked polymer binding agent. The polymer binding agent is of a three-dimensional network structure and is formed through in-situ polymerization of chitosan, at least one of polymers containing a carboxyl group or a carboxylate group, and at least one of micromolecule polybasic carboxylic acid and micromolecule polybasic carboxylate. An amidogen group on a chitosan molecular chain and a carboxyl group of the other polymer form a three-dimensional network structure in situ through electrostatic interaction at the room temperature, and dispersion uniformity of active materials in the electrode is improved. When the polymer binding agent is in use, a pole piece is subjected to further heat treatment, the cross-linking effect of the polymer chains is enhanced, and the stability of the electrode structure in the cycle process is improved. The electrochemical performance of the electrode of the lithium ion battery can be improved when the in-situ cross-linked polymer binding agent is used for preparing the electrode in situ, and particularly a more obvious improving effect is achieved on high specific capacity positive pole lithium-rich materials, a negative pole silicon substrate, tin-based materials and Li-S-based materials.

Description

technical field [0001] The invention relates to an in-situ cross-linked polymer binder for lithium ion batteries and an electrode of lithium ion batteries prepared by using the polymer binder. Background technique [0002] Lithium-ion batteries have the advantages of high specific energy, high working voltage, and long cycle life, and have been developed rapidly since their commercialization. With the application of lithium-ion batteries in the field of hybrid electric vehicles and electric vehicles, the demand for lithium-ion batteries with high energy density is increasing. However, electrode materials with higher specific capacity are often accompanied by larger volume changes during the intercalation / delithiation process. In the long-term cycle process, this volume change will lead to the deterioration of the electrode structure, resulting in accelerated capacity decay of the electrode and shortening the cycle life of lithium-ion batteries with high specific capacity. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/13H01M10/0525
CPCH01M4/13H01M4/622H01M10/0525H01M4/62Y02E60/10
Inventor 杨娟玉卢世刚武兆辉于冰闫坤史碧梦
Owner GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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