Quasi-solid polymer electrolyte for lithium ion secondary battery and preparation method thereof

A secondary battery and polymer technology, applied in secondary batteries, circuits, electrical components, etc., can solve the problems of low conductivity of solid polymer electrolyte, poor battery cycle rate performance, poor adhesion, etc., to achieve high Interfacial stability and electrochemical performance, improvement of cycle rate performance, and improvement of electrical conductivity

Active Publication Date: 2017-01-18
CENT SOUTH UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the conductivity of the solid polymer electrolyte is low, and due to poor adhesion, it makes poor contact with the positive and negative electrodes, resulting in poor cycle rate performance of the battery

Method used

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  • Quasi-solid polymer electrolyte for lithium ion secondary battery and preparation method thereof
  • Quasi-solid polymer electrolyte for lithium ion secondary battery and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (I) Under the condition of nitrogen protection, 2 milliliters of polyethylene glycol methyl ether methacrylate monomer PEGMEM with EO segment number of 9, 1 milliliter of octadecyl methacrylate SMA and 0.00302 grams of initiator 2,2'-Azobisisobutyronitrile was added to a mixed medium of 7 ml of ethyl acetate and 5 ml of n-hexane to fully dissolve;

[0023] (II) The above organic solution was reacted at 70°C for 24 hours to obtain a PEGMEM-co-SMA copolymer adhesive system, THF was stirred and dissolved, petroleum ether was precipitated and washed, centrifuged, and vacuum-dried to obtain PEGMEM-co-SMA without Shaping highly adhesive solids;

[0024] (Ⅲ) Using tetrahydrofuran as a solvent, lithium bistrifluoromethanesulfonate imide (chemical formula: LiN(CF 3 SO 2 ) 2 ) dope with PEGMEM-co-SMA copolymer according to the ratio of Li:EO=1:10, stirring and dissolving;

[0025] (IV) Drop the solution obtained in the previous step onto the non-woven fabric, and after the te...

Embodiment 2

[0027] The electrolyte prepared in Example 1 is in a quasi-solid form with a fixed shape and a certain fluidity, and forms a polymer film on the shaped substrate. The polymer film is composed of polyethylene glycol methyl ether methacrylate monomer and methyl A copolymer formed of octadecyl acrylate and doped with lithium trifluoromethanesulfonate imide, wherein the number of oxyethylene (EO) segments in the polyethylene glycol methyl ether methacrylate monomer is 9, Li and The molar ratio of oxyethylene EO is 1:10.

Embodiment 3

[0029] With tetrahydrofuran as a solvent, lithium trifluoromethanesulfonate (chemical formula: LiCF 3 SO 3 ) is doped with the PEGMEM-co-SMA copolymer according to the ratio of Li:EO=1:25, 1:20, 1:15, 1:10, 1:8 and 1:5, stirred and dissolved, and the mixed solution is dropped into On the non-woven fabric, after the solvent volatilizes and vacuum-dries, a quasi-solid high-adhesion polymer electrolyte is obtained, and the conductivity at different temperatures is as follows: figure 1 . from figure 1 It can be seen that when Li:EO=1:25, the conductivity of the polymer electrolyte is the highest, which is 2.44×10 at 25 degrees - 5 S / cm, 1.21×10 at 100 degrees -3 S / cm, the conductivity order of magnitude is 10 -3 The practical application requirements have been met. )

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Abstract

The invention provides a quasi-solid polymer electrolyte for a lithium ion secondary battery and a preparation method. The electrolyte has a fixed shape and is in a quasi-solid mode with certain fluidity, and a polymer membrane is a copolymer formed by PEGMEM (poly (ethylene glycol)methyl ether methacrylate) monomers and SMA (stearyl methacrylate) monomers and doped with organic lithium salt. The PEGMEM-co-SMA amorphous solid prepared through a polymerization reaction is doped with the organic lithium salt to obtain a mixture, and the mixture is dissolved in an organic solution, is dropped on a diaphragm material and is subjected to vacuum drying by an evaporation solvent to obtain the polymer electrolyte. According to the PEGMEM-co-SMA copolymer, crystallization of ethylene oxide (EO) segments in the PEGMEM monomers is effectively inhibited, the electrical conductivity of the all-solid-state polymer electrolyte is improved, further, the polymer appearance is in a high-adhesion amorphous state, the polymer can be sufficiently contacted with a positive pole and a negative pole and has high interface stability and electrochemical performance, and accordingly, the circulating rate performance of the battery is improved.

Description

technical field [0001] The invention relates to a material for a lithium ion secondary battery and a preparation method thereof, in particular to an electrolyte for a lithium ion secondary battery and a preparation method thereof. Background technique [0002] Electrolyte is an essential part of lithium-ion batteries. It not only plays the role of conducting current and transporting ions between the positive and negative electrodes, but also plays an important role in the specific energy, safety, cycle performance, rate performance and cost of the battery. the key influencing factors. [0003] At present, the electrolyte used in traditional lithium-ion secondary batteries is an organic liquid electrolyte. Because of its early research, mature technology and low cost, it occupies 90% of the current finished lithium-ion battery market. However, since the liquid electrolyte is an organic substance with a low flash point, it will ignite the electrolyte in the case of high curre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/0565
CPCY02E60/10
Inventor 韦伟峰张锦芳马骋陈立宝
Owner CENT SOUTH UNIV
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