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Ionic polymer/ceramic composite membrane material, preparation method thereof and lithium secondary battery

A technology of ionic polymers and composite membranes, which is applied to battery components, circuits, electrical components, etc., can solve problems affecting the application of ionic polymer membranes, battery short circuit, insufficient rigidity, etc., and achieve good liquid absorption and liquid retention capabilities , improve the cycle life, improve the effect of electronic insulation performance

Active Publication Date: 2014-02-26
CHENGDU ZHONGKE LAIFANG POWER SCI & TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The main problems of polyolefin microporous membranes: First, the microporous membranes have poor liquid absorption and liquid retention capabilities. PP or PE is a non-polar material, which has poor affinity with highly polar electrolyte solutions. The low affinity of the polyolefin microporous membrane leads to the poor ability of the microporous membrane to absorb and retain the electrolyte, and the strength of the liquid absorption and liquid retention of the microporous membrane is closely related to the charge-discharge cycle life of the battery. The second is that the thermal stability of the microporous membrane is poor. Because the polyolefin microporous membrane is mechanically stretched to cause pores, or mechanically stretched and then extracted with an organic solvent to cause pores, and the microporous membrane is heat-set. This preparation process makes the microporous membrane have residual stress, which makes the microporous membrane have a shape memory effect. When the polyolefin resin is heated to a temperature close to the softening point, the microporous membrane tends to recover the shape before stretching, and produces a large Shrinkage, thermal shrinkage of the microporous membrane must be accompanied by volume shrinkage, and the shrinkage of the membrane area will cause the microporous membrane to lose the barrier effect between the positive and negative electrodes, thereby short-circuiting the positive and negative electrodes inside the battery, causing safety problems such as battery combustion and explosion.
The inventors of the present invention found in research that acrylate polymers are used as film-forming substances in patent application No. 201210181362.6, and the prepared ionic polymer membranes have good flexibility, but insufficient rigidity, resulting in large deformation during use , affecting the application of ionic polymer membranes in lithium-ion batteries

Method used

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  • Ionic polymer/ceramic composite membrane material, preparation method thereof and lithium secondary battery
  • Ionic polymer/ceramic composite membrane material, preparation method thereof and lithium secondary battery
  • Ionic polymer/ceramic composite membrane material, preparation method thereof and lithium secondary battery

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preparation example Construction

[0046] The ionic polymer / ceramic filler composite membrane provided by the invention is prepared by the following method:

[0047] 1. First synthesize the polymer colloidal emulsion containing anionic groups on the surface, add the colloidal protective agent and distilled water into the reaction flask, heat and stir until completely dissolved; then keep the temperature of the reactor constant to the required reaction temperature of 50-90°C, and 60~70℃ is better, add reactive sulfonate surfactant, methyl acrylate, second monomer and crosslinking agent at one time, then add initiator to initiate polymerization, or add 1 / 5~1 / 3 first The reactive sulfonate surfactant and methyl acrylate, then dropwise or step-by-step add the remaining reactive sulfonate surfactant and methyl acrylate and the second monomer and crosslinking agent, polymerization reaction 4~ 36 hours, preferably 8 to 24 hours.

[0048] 2. Preparation of pre-dispersed ceramic filler slurry. Add ceramic filler and di...

Embodiment 1

[0062] Embodiment 1 does not contain the comparative film of ceramic filler

[0063] Synthesis of polymer colloidal emulsion: In a four-port reaction vessel with condensed water, add 1000g of distilled water and 51g of polyvinyl alcohol with a degree of polymerization of 1700 and a degree of hydrolysis of 99%, then raise the temperature to 92°C, stir and dissolve, and wait for the polyethylene After the alcohol is completely dissolved, cool to 60°C, add 156g methyl acrylate (MA) monomer, 10g allyloxyhydroxypropyl sodium sulfonate (AHPS) and 10g cross-linking agent methylenebisacrylamide and stir for 1h, add 2g Ammonium persulfate initiates polymerization. After the reaction is carried out for 6 hours, 100g (MA) and 5gAHPS are added, and 1.5g ammonium persulfate is added to continue polymerization for 10 hours to obtain a white polymer colloidal emulsion with a solid content of 23.9%. The conversion rate is 96%.

[0064] The average particle size (D50) of the colloidal particl...

Embodiment 2

[0069]The preparation of embodiment 2 ionic polymer / ceramic filler composite membrane

[0070] Get polymer colloid emulsion 100g, Al 2 o 3 Slurry 12.4g was placed in a three-necked flask and stirred for 10 hours to obtain a homogeneously dispersed polymer colloidal emulsion and Al 2 o 3 Slurry mixture slurry, and then use the casting coating method to coat the mixture slurry on the PET (polyethylene terephthalate) base tape, after drying the water, peel off to obtain a film with a thickness of 20-25 μm Ionomer / Al 2 o 3 Composite film, where, Al 2 o 3 The mass percentage in the film is 10%.

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Abstract

The invention relates to an ionic polymer / ceramic composite membrane material, a preparation method thereof and a lithium secondary battery and belongs to the field of manufacturing of lithium batteries. The ionic polymer / ceramic filler composite membrane material is a pore-free dense membrane which is formed by a ceramic filler and a polymer colloidal particle which has a sulfonate group on the surface, and an evident thermal contraction can not happen to a diaphragm after a battery is overheated. When an ionic polymer / ceramic filler composite membrane absorbs an electrolyte, a penetrating ionic conduction path is formed among colloidal particles, and after the ionic polymer / ceramic filler composite membrane absorbs the electrolyte solution or a solvent, a colloid particle structure is still maintained. By means of the dense stacking of sphere structures of the colloidal particles and ceramic filler particles which are uniformly distributed in the membrane, the sinuosity of the ionic conduction path is increased, an electronic insulation performance of a polymer electrolyte membrane is improved, simultaneously the rigidity of the ionic polymer membrane is improved due to the presence of the ceramic filler particles, and the deformation of the ionic polymer membrane is reduced.

Description

technical field [0001] The invention relates to a diaphragm material used for energy storage devices such as lithium-ion secondary batteries and a preparation method thereof, belonging to the field of lithium battery manufacturing. Background technique [0002] The battery is composed of positive electrode, negative electrode, separator and electrolyte. The separator is one of the important components in the battery. Its function in the battery is to act as a separator between the positive and negative electrodes inside the battery to prevent the internal short circuit caused by direct contact between the positive and negative electrodes. The ions pass through smoothly to support the electrochemical reaction of the battery. [0003] The current commercialized lithium-ion batteries, metal lithium secondary batteries, and lithium-sulfur batteries are mainly used in battery separators, mainly polyolefin microporous membranes. There are two technical routes for the production ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L33/08C08K3/00C08K3/22C08J5/18C08F261/04C08F283/06C08F265/02C08F271/02C08F220/14C08F228/02C08F220/06C08F220/58C08F212/14H01M2/16
CPCY02E60/12Y02E60/10
Inventor 潘中来黄兴兰马先果邓佳闽王璐高建东杜鸿昌李仁贵邓正华
Owner CHENGDU ZHONGKE LAIFANG POWER SCI & TECH CO LTD