Membrane protecting coating for preventing dendrite short circuit of metal negative electrode and preparation method thereof

A protective coating and diaphragm technology, applied in the direction of circuits, electrical components, battery pack components, etc., can solve problems such as metal negative electrode short circuit, achieve the effect of preventing battery short circuit, reducing battery polarization, and maintaining energy efficiency

Inactive Publication Date: 2017-05-31
NO 63971 TROOPS PLA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the metal negative electrode is easy to form dendrites and cause short circuit during the charging and discharging process of the battery. A binder that can also chelate and adsorb metal ions is added to the chelating resin with chelating and strong adsorption, mixed with a solvent to prepare a slurry, and coated or sprayed with a protective coating on one or both sides of the battery separator , so as to prevent metal dendrites from piercing the diaphragm and short-circuiting, while not affecting the conduction of electrolyte ions on both sides of the diaphragm, and due to the strong adsorption and chelation of the chelating resin, the ion conductivity in the solution can be effectively improved , reduces the solution resistance, improves battery energy utilization efficiency and cycle stability, and prolongs service life

Method used

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  • Membrane protecting coating for preventing dendrite short circuit of metal negative electrode and preparation method thereof
  • Membrane protecting coating for preventing dendrite short circuit of metal negative electrode and preparation method thereof
  • Membrane protecting coating for preventing dendrite short circuit of metal negative electrode and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Lithium polyacrylate (molecular weight: 10,000), a binder capable of chelating and adsorbing lithium ions, is mixed with acetylene black at a mass ratio of 80:20, then an organic solvent-N-methylpyrrolidone is added, stirred and mixed in a vacuum to prepare a slurry . The length and width are respectively 100mm and 50mm polypropylene celgard diaphragm (0.02mm) on the coating machine, the above-mentioned slurry is coated on the diaphragm surface, the thickness of the coating is controlled at 120um, then placed in a vacuum oven for 60 ℃ vacuum to remove the solvent and dry for 12h. Using the diaphragm covered with a lithium polyacrylate-carbon protective layer on one side, a Cu-Li half-cell is assembled with a metal lithium negative electrode on a copper foil, and the electrolyte is a solution of lithium hexafluorophosphate, ethylene carbonate, and diethyl carbonate. The test current is 0.31mA cm -2 , after 400 lithium deposition-dissolution cycles, a large number of de...

Embodiment 2

[0038]Add 55% binder polyacrylic acid lithium (molecular weight 10000) in the polyaminophosphonic acid resin that has chelation and adsorption to lithium ions but does not have adhesion, then add organic solvent-N-methylformamide, vacuum Stir to mix to make a slurry. Spread the polypropylene celgard membrane (0.02mm) with a length and width of 80mm and 60mm on the coating machine, and coat the above-mentioned slurry on the surface of the membrane. The thickness of the coating is controlled at 130um, and then placed in a vacuum of 0.1 Remove the solvent and dry in an MPa vacuum oven at 60° C. for 12 hours. Using the diaphragm covered with polyacrylate lithium-chelating resin inert protective coating on one side, a Cu-Li half-cell is assembled with metal lithium negative electrode and copper foil, and the electrolyte is lithium hexafluorophosphate, ethylene carbonate, and diethyl carbonate solution. The test current is 0.31mA cm -2 , after 500 lithium deposition-dissolution cy...

Embodiment 3

[0040] Add 30% binder lithium polyacrylate (molecular weight: 10000) into the non-adhesive chelating resin zinc polyacrylate, then add water and ethanol mixed solvent, and vacuum stir and mix to prepare slurry. Use a spray gun to repeatedly spray the above slurry on the glass fiber diaphragm with a length and width of 80mm and 40mm respectively, so that the above slurry completely covers the surface of the glass fiber diaphragm. The thickness of the coating is 80um and placed in a vacuum with a vacuum degree of 0.1MPa. Vacuumize and remove the solvent in an oven at 80°C for 10 h. Spray the other side of the glass fiber diaphragm in the same way, and dry it in vacuum for 10 hours. The thickness of the coating is 80um. The diaphragm covered with polyacrylic acid zinc protective layer on both sides is adopted, a Cu-Zn half cell is assembled with metal zinc negative electrode and copper foil, and the electrolyte solution is lithium sulfate and zinc sulfate aqueous solution. The t...

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Abstract

The invention relates to a membrane protecting coating for preventing a dendrite short circuit of a metal negative electrode and a preparation method thereof. Slurry is prepared through adding an adhesive and a solvent which have adhesivity and ion adsorption action to a carbon material or a high polymer which has strong chelation action and strong adsorption action but does not have adhesivity on metal ions; and the protecting coating coats or sprays the single surface or double surfaces of a battery membrane, and the surface and the edge are covered with the protecting coating, so that the process complexity and dangerousness of direct modification of the high-activity metal surface are avoided, and the effect of preventing the short circuit of the battery due to the fact that metallic dendrites puncture the membrane is achieved. The preparation method is simple and feasible, and is widely applied to a secondary battery system which directly takes high-capacity and high-activity metal as the negative electrode; the charge-discharge efficiency of the metal negative electrode is improved; and a guarantee is provided for long-cycle life of the battery.

Description

technical field [0001] The invention relates to a diaphragm protective coating for preventing dendrite short circuit of a metal negative electrode and a preparation method thereof, belonging to the fields of materials and chemical power sources. Background technique [0002] Compared with graphite anodes for lithium-ion batteries that have been commercially used at present, metal lithium has extremely high theoretical specific capacity (3860mAh / g), the most negative reduction potential (-3.04V, relative to hydrogen standard potential) and extremely small density. (0.59g / cm 3 ), has long been regarded as a highly competitive anode material for high-capacity organic-based secondary batteries. However, during the battery charging process, metal lithium dendrites are easily formed, resulting in dead lithium and pulverization, resulting in a decrease in the battery Coulombic efficiency and active material utilization, and even internal short circuits, thermal failure or explosio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16
CPCH01M50/403H01M50/449Y02E60/10
Inventor 文越华王安邦王维坤赵鹏程张文峰曹高萍杨裕生
Owner NO 63971 TROOPS PLA
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