Solid-state battery and preparation method and application thereof

A solid-state battery, solid-state electrolyte technology, applied in the field of lithium-ion batteries, can solve the problems of poor cycle performance of solid-state batteries, and achieve the effect of excellent cycle stability performance

Pending Publication Date: 2022-07-29

河北光兴半导体技术有限公司 +1

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AI-Extracted Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to solve the problem...

Abstract

The invention relates to the technical field of lithium ion batteries, and discloses a solid-state battery and a preparation method and application thereof. The solid-state battery comprises stacked battery cells, and each battery cell comprises a positive electrode, a negative electrode and a composite electrolyte arranged between the positive electrode and the negative electrode; the composite electrolyte comprises a first electrolyte and second electrolytes arranged on the two sides of the first electrolyte, the first electrolyte is a solid electrolyte membrane, and the second electrolytes are obtained by curing electrolyte containing additives. According to the solid-state battery provided by the invention, the solid-state electrolyte and the liquid-state electrolyte containing the additive are organically combined, so that the interface impedance between the electrolyte and the positive electrode and between the electrolyte and the negative electrode can be remarkably enhanced, and the solid-state battery with excellent cycle stability can be obtained.

Application Domain

Secondary cells servicing/maintenanceElectrolyte accumulators manufacture

Technology Topic

Solid-state batteryCyclic stability +10

Image

Examples

Experimental program(6)
Comparison scheme(3)
Effect test(1)

Example Embodiment

[0062] The present invention has no special requirements on the preparation method of the positive electrode sheet and the negative electrode sheet, and can be prepared by methods known in the art.

[0063] The present invention has no special requirements on the preparation method of the battery core, which can be carried out by a method known in the art, for example, it can be prepared by a lamination or winding method.

[0064] In the present invention, the electrolyte is solidified during the chemical conversion process, that is, the chemical conversion conditions at least include: a vacuum degree of 0.8-2MPa, a temperature of 80-120°C, and a time of 12-30h. The inventors found that by adopting the specific embodiment in this preferred case, the prepared solid-state battery has more excellent cycle stability.

[0065] According to a particularly preferred embodiment, in step (3), the second solvent is ethanol.

[0066] Preferably, in step (3), the amount of the second solvent accounts for 0.05-0.2wt% of the amount of the electrolyte.

[0067] Preferably, in step (3), the conditions of the air extraction treatment at least include: the pressure is a negative pressure of 0.5 MPa to a negative pressure of 0.1 MPa.

[0068] As mentioned above, the third aspect of the present invention provides the application of the solid-state battery described in the first aspect in energy storage devices, electric vehicles, and electronic products.

[0069] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, various raw materials and instruments used are commercially available.

[0070] Solid electrolyte: lithium aluminum titanium phosphate, purchased from Shenzhen Kejingzhida Technology Co., Ltd.;

[0071] Binder: polyvinylidene fluoride, the brand is Arkema LBG, purchased from Dongguan Taotao Plastic Materials Co., Ltd.;

[0072] Lithium salt: Lithium bis-trifluoromethanesulfonic acid imide, purchased from Aladdin Reagent Company;

[0073] The first solvent: dimethylacetamide, purchased from Aladdin Reagent Company;

[0074] Positive electrode sheet: Lithium iron phosphate, polyvinylidene fluoride, and conductive carbon black are mixed in N-dimethylamide in a mass ratio of 8:1:1, uniformly coated on aluminum foil with a thickness of 100 μm, and then heated at 100 °C After drying for 2 hours, cut it into a 5×4mm circular electrode sheet;

[0075] Negative sheet: graphite, polyvinylidene fluoride, and conductive carbon black are mixed in N-dimethylamide in a mass ratio of 8:1:1, uniformly coated on copper foil with a thickness of 80 μm, and then heated at 100 °C After drying for 2 hours, cut it into a circular electrode sheet of 5.2 × 4.2 mm;

[0076] PP/PE/PP three-layer microporous composite membrane diaphragm: model 2300, purchased from Celgard Company;

[0077] In the following examples, the electrolyte salts in the electrolyte are all lithium hexafluorophosphate with a concentration of 1 mol/L, and the organic solvents are the combination of ethylene carbonate and dimethyl carbonate with a mass ratio of 1:1.

Example Embodiment

[0078] Example 1

[0079] This embodiment provides a method for preparing a solid-state battery, comprising the following steps:

[0080] (1) the solid electrolyte (the amount of solid electrolyte is 5g), the binder and the lithium salt are dissolved in the first solvent according to the mass ratio of 1:0.5:0.1, and the first contact mixing is carried out to obtain the first mixed solution, and Casting the first mixed solution in a polytetrafluoroethylene circular mold for drying to obtain a solid electrolyte membrane with an average thickness of 100 μm;

[0081] Wherein, the conditions of the first contact mixing are: the stirring speed is 300rpm, the temperature is room temperature, and the time is 8h;

[0082] The conditions of drying treatment are: the vacuum degree is negative pressure 100Pa, the temperature is 100℃, and the time is 24h;

[0083] (2) Stack the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet in turn, and weld the tabs, and wind them into a standard 26650 cylindrical battery cell through a winding machine;

[0084] (3) Introducing 5g of electrolyte solution containing 1wt% acrylamide and 0.1wt% ethanol into the battery cell for chemical conversion treatment, the minimum distance between the two surfaces of the formed second electrolyte along the stacking direction of the battery cell is 2 μm, the maximum The distance is 5 μm. After the formation of capacity is completed, it is assembled and formed, and then the cell is subjected to air extraction treatment, and finally the solid-state battery S1 is obtained by packaging;

[0085] Among them, the conditions of the chemical formation treatment are: the temperature is 100°C, the pressure is 1.5MPa, and the time is 0.5h;

[0086] The conditions of the pumping treatment are as follows: the pressure is a negative pressure of 0.1 MPa.

Example Embodiment

[0087] Example 2

[0088] This embodiment provides a method for preparing a solid-state battery, comprising the following steps:

[0089] (1) the solid electrolyte (the amount of solid electrolyte is 5g), the binder and the lithium salt are dissolved in the first solvent according to the mass ratio of 1:0.6:0.2, and the first contact mixing is carried out to obtain the first mixed solution, and Casting the first mixed solution in a polytetrafluoroethylene circular mold for drying to obtain a solid electrolyte membrane with an average thickness of 100 μm;

[0090] Wherein, the conditions of the first contact mixing are: the stirring speed is 300rpm, the temperature is room temperature, and the time is 8h;

[0091] The conditions of drying treatment are: the vacuum degree is negative pressure 300Pa, the temperature is 100℃, and the time is 24h;

[0092] (2) Stack the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet in turn, and weld the tabs, and wind them into a standard 26650 cylindrical battery cell through a winding machine;

[0093] (3) Introducing 5g of electrolyte solution containing 0.5wt% acrylamide and 0.1wt% ethanol into the battery cell for chemical formation treatment, the minimum distance between the two surfaces of the formed second electrolyte along the stacking direction of the battery cell is 3 μm, The maximum distance is 5μm. After forming the capacity, it is assembled and formed, and then the battery core is subjected to air extraction treatment, and finally the solid-state battery S2 is obtained by packaging;

[0094] Among them, the conditions of the chemical formation treatment are: the temperature is 120°C, the pressure is 1.0MPa, and the time is 0.5h;

[0095] The conditions of the pumping treatment are as follows: the pressure is a negative pressure of 0.1 MPa.

PUM

Property	Measurement	Unit
The average thickness	80.0 ~ 120.0	µm
The average thickness	100.0	µm
Thickness	100.0	µm

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