Cyanate ester modified PVDF binder, positive pole piece applying same and lithium-sulfur battery

A technology of lithium-sulfur battery and positive pole piece, which is applied in lithium batteries, battery electrodes, non-aqueous electrolyte batteries, etc., can solve the problems of low F atom polarizability, low polymer flexibility, and poor adhesion, etc. Achieve the effect of alleviating the shuttle effect, improving the adhesion, and improving the electrical conductivity

Inactive Publication Date: 2018-09-21
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the polarizability of F atoms is low, making PVDF polymers highly insulating
On the other hand, the higher regular arrangement of PVDF molecular chains makes the crystallinity higher, so the flexibility of the polymer is lower, and its use as a binder for lithium-sulfur batteries will make its adhesion to aluminum foil materials worse

Method used

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  • Cyanate ester modified PVDF binder, positive pole piece applying same and lithium-sulfur battery
  • Cyanate ester modified PVDF binder, positive pole piece applying same and lithium-sulfur battery
  • Cyanate ester modified PVDF binder, positive pole piece applying same and lithium-sulfur battery

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Effect test

Embodiment 1

[0026] In this embodiment, the cyanate-modified PVDF binder contains the cyanate-modified PVDF binder which is polymerized from monomer vinylidene fluoride and isocyanate-based monomers, and its structural formula is as follows:

[0027]

[0028] Among them, R 1 is hydrogen or R 1 from C 1-8 straight-chain or branched-chain alkyl; R 2 is hydrogen or R 2 from C 1-8 straight-chain or branched-chain alkyl; m and n are both integers greater than 0.

[0029] The preparation method of the above-mentioned cyanate ester modified PVDF binder is as follows: put PVDF into 2mol / L NaOH aqueous solution and stir, then wash and dry to obtain a PVDF sample containing double bonds, and mix the sample and dimethyl isocyanate powder by pressing Add to the acetone solvent with a mass ratio of 3:1, then add N,N-dimethylformamide (DMF), control the temperature and pre-mix at 80°C for 0.5h, remove the organic solvent; finally add dicumyl peroxide (DCP), under the protection of an inert gas,...

Embodiment 2

[0035] In this embodiment, the cyanate-modified PVDF binder contains the cyanate-modified PVDF binder which is polymerized from monomer vinylidene fluoride and isocyanate-based monomers, and its structural formula is as follows:

[0036]

[0037] Among them, R 1 is hydrogen or R 1 from C 1-8 straight-chain or branched-chain alkyl; R 2 is hydrogen or R 2 from C 1-8 straight-chain or branched-chain alkyl; m and n are both integers greater than 0.

[0038]The preparation method of the above-mentioned cyanate-modified PVDF binder is as follows: put PVDF into NaOH aqueous solution and stir, then wash and dry to obtain a PVDF sample containing double bonds, and add the mixed powder of the sample and dimethyl isocyanate to acetone Add N,N-dimethylformamide (DMF) to the solvent, pre-mix at 80°C for 0.5 h under temperature control, then remove the organic solvent; finally add dicumyl peroxide (DCP), under inert gas protection Control the temperature at 100°C, stir for 1-2 hour...

Embodiment 3

[0044] In this embodiment, the cyanate-modified PVDF binder contains the cyanate-modified PVDF binder which is polymerized from monomer vinylidene fluoride and isocyanate-based monomers, and its structural formula is as follows:

[0045]

[0046] Among them, R 1 is hydrogen or R 1 from C 1-8 straight-chain or branched-chain alkyl; R 2 is hydrogen or R 2 from C 1-8 straight-chain or branched-chain alkyl; m and n are both integers greater than 0.

[0047] The preparation method of the above-mentioned cyanate-modified PVDF binder is as follows: put PVDF into NaOH aqueous solution and stir, then wash and dry to obtain a PVDF sample containing double bonds, and add the mixed powder of the sample and dimethyl isocyanate to acetone Add N,N-dimethylformamide (DMF) to the solvent, pre-mix at 80°C for 0.5 h under temperature control, then remove the organic solvent; finally add dicumyl peroxide (DCP), under inert gas protection Control the temperature at 100°C, stir for 1-2 hou...

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Abstract

The invention discloses a cyanate ester modified PVDF binder, a positive pole piece applying the same and a lithium-sulfur battery. The cyanate ester modified PVDF binder is formed by polymerizing a monomer vinylidene fluoride and an isocyanate monomer. A cyanate ester modified PVDF binder molecular chain contains cyan functional groups, the electrical conductivity of the positive pole piece can be improved, and polysulfide in the battery cyclic process can be effectively adsorbed, so that the initial discharge capacity and cyclic stability of the lithium-sulfur battery are improved, and the shuttle effect of the lithium-sulfur battery is relieved; in addition, the cyan functional groups contained in the binder can form hydrogen-bond interaction with oxidizing functional groups on the surface of aluminum foil, the bonding power of the positive pole piece is improved, the phenomenon that active substances fall off in repeated charge-discharge cycles is avoided, the multiplying power property of the battery charge-discharge cycles is improved, and the recycling service life is prolonged.

Description

technical field [0001] The invention relates to the technical field of lithium-sulfur batteries, in particular to a cyanate ester-modified PVDF binder, a positive pole piece using the binder, and a lithium-sulfur battery. Background technique [0002] With the depletion of non-renewable resources such as coal, oil, and natural gas, the development and research of new energy technologies have attracted the attention of scientists, among which the development of high-energy-density secondary batteries is the key to energy storage. At present, the energy density of commercialized lithium-ion batteries is around 150Wh / kg, but due to the limitations of the inherent properties of the positive electrode material, there is not much room for improvement in the energy density of lithium-ion batteries. Therefore, researchers are actively developing cathode materials with higher energy densities. Elemental sulfur, as a light-weight, multi-electron reaction positive electrode active mat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M10/052
CPCH01M4/622H01M10/052Y02E60/10
Inventor 王涂亮梁大宇
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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