A solid-state metal battery with an integrated positive electrode / electrolyte structure

Abstract

A solid-state metal battery with an integrated positive electrode / electrolyte structure comprises a basic battery unit, the basic battery unit comprises a composite positive electrode sheet, a solid-state electrolyte and a metal negative electrode sheet which are sequentially laminated, the material of the solid-state electrolyte is a dynamic supramolecular ion conductive elastomer; the composite positive electrode sheet comprises a current collector and a bonding layer coated on the current collector, the composite positive electrode sheet is attached to the solid-state electrolyte through the bonding layer, the bonding layer comprises a binder and positive electrode particles and a conductive agent doped in the binder, and the material of the binder is a dynamic supramolecular ion conductive elastomer. The solid-state metal battery has a long battery cycle life, high safety, high specific capacity and high energy density, can meet the flexible wearing requirements (folding, bending and rolling), can be mass produced and assembled, is suitable for industrial biochemical production, and meets the requirements of various energy storage fields.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid-state metal batteries, in particular to a solid-state metal battery with integrated positive electrode / electrolyte structure. BACKGROUND

[0002] Solid-state batteries have high specific energy, high safety, long service life, high reliability, small volume, flexibility, etc., and can meet the various needs of energy storage in electric vehicles, flexible electronic products, aerospace, etc. It is an important direction for the development of future energy storage power supplies. Solid-state batteries replace liquid electrolytes and separators with solid-state electrolytes, which can fundamentally solve the safety problems caused by the volatility, leakage and combustion of traditional liquid electrolytes, and can reduce the volume by 40% and the mass by 25%. Among them, solid-state batteries that replace liquid organic electrolytes with solid-state electrolytes have become a key technology in the next generation of energy storage. Among common solid-state electrolytes, polymer solid-state electrolytes have the advantages of light weight, flexibility, easy processing, safety and reliability, and low price, and have great potential in realizing high specific energy, long cycle and high safety of solid-state batteries in practical applications.

[0003] Polymer solid-state electrolytes are composed of a polymer matrix and a lithium salt composite, and their ion transport mainly depends on two processes: the dissociation of lithium salt by polar groups such as C-O, C=O, and C≡N on the polymer chain segment, and the movement of amorphous chain segments on the polymer chain segment to promote Li + The repeated "coordination-dissociation" process realizes ion transport, thereby providing high ionic conductivity. However, the current polymer solid-state electrolytes still have the following shortcomings: a narrow electrochemical stability window, which limits the energy density of solid-state batteries; poor mechanical properties, which cannot effectively prevent metal dendrites from penetrating the electrolyte and causing battery short circuits; and both flexibility and safety performance need to be improved. SUMMARY

[0004] Therefore, the present application provides a solid-state metal battery with an integrated positive electrode / electrolyte structure to solve the technical problems that the electrochemical performance, mechanical properties, safety performance, etc. of the metal battery of the existing polymer solid-state electrolyte still need to be further improved.

[0005] To achieve the above object, the application provides a solid-state metal battery with an integrated positive electrode / electrolyte structure, which comprises a basic battery unit, the basic battery unit comprises a composite positive electrode sheet, a solid-state electrolyte and a metal negative electrode sheet which are sequentially laminated, the material of the solid-state electrolyte is a dynamic supramolecular ion-conducting elastomer; the composite positive electrode sheet comprises a current collector and a bonding layer coated on the current collector, the composite positive electrode sheet is attached to the solid-state electrolyte through the bonding layer, the bonding layer comprises a binder and positive electrode particles and a conductive agent doped in the binder, the material of the binder is a dynamic supramolecular ion-conducting elastomer; the dynamic supramolecular ion-conducting elastomers for the solid-state electrolyte and the bonding layer are both formed by compounding a dynamic supramolecular elastomer as a polymer matrix with an electrolyte salt.

[0006] As a further preferred technical solution of the application, in the bonding layer, the mass ratio of the positive electrode particles, the conductive agent and the dynamic supramolecular ion-conducting elastomer is 2:1:7-8:1:1.

[0007] As a further preferred technical solution of the application, the positive electrode particles are one or more of lithium cobaltate, lithium iron phosphate, lithium manganate, lithium titanate, nickel cobalt manganese, sodium vanadium fluorophosphate, Prussian blue and potassium vanadium fluorophosphate; the conductive agent is one or more of super-p, acetylene black, carbon nanotube and graphene.

[0008] As a further preferred technical solution of the application, the thickness of the solid-state electrolyte is 1 μm-1 mm.

[0009] As a further preferred technical solution of the application, the electrolyte salt is a lithium salt, a sodium salt, a potassium salt, a zinc salt, a magnesium salt or a calcium salt, and the electrolyte salt accounts for 5%-70% of the mass of the dynamic supramolecular elastomer.

[0010] As a further preferred technical solution of the application, the current collector is an aluminum foil or a carbon-coated aluminum foil.

[0011] As a further preferred technical solution of the application, the metal negative electrode sheet is lithium metal, sodium metal, potassium metal, magnesium metal or calcium metal.

[0012] As a further preferred technical solution of the application, the solid-state metal battery is a button cell or a soft-packaged battery, and the solid-state metal battery is encapsulated with at least one layer of the basic battery unit.

[0013] The solid-state metal battery with an integrated positive electrode / electrolyte structure of the application has the following beneficial effects by adopting the above technical solution:

[0014] 1) The dynamic composite cathode or self-supporting composite cathode in the present application uses a dynamic supramolecular ion-conducting elastomer as a binder, in addition, the solid-state electrolyte also uses a dynamic supramolecular ion-conducting elastomer, both the binder and the solid-state electrolyte utilize the reversibility of the dynamic supramolecule to help build a solid-state metal battery with an integrated cathode / ultra-thin solid-state electrolyte structure, so that the solid-state electrolyte is ultra-thin, which can be less than 100 um, and the minimum can reach 1 um;

[0015] 2) The solid-state metal battery with an integrated cathode / ultra-thin solid-state electrolyte structure built in the present application can be stably cycled for more than 300 cycles, and the capacity retention rate can reach more than 80%, and the coulombic efficiency can reach more than 99%;

[0016] 3) The solid-state metal battery of the present application has long battery cycle life, high safety, high specific capacity, high energy density, and can meet the flexible wearing demand (foldable, bendable, and rollable), can be mass produced and assembled, is suitable for industrial biochemical production, and at the same time meets the demand of various energy storage fields. BRIEF DESCRIPTION OF DRAWINGS

[0017] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0018] Figure 1 Structure schematic diagram of an example of the solid-state metal battery with an integrated cathode / electrolyte structure of the present application;

[0019] Figure 2 SEM image of the full solid-state lithium metal battery of Example 1 of the present application;

[0020] Figure 3 Long cycle curve diagram of the full solid-state lithium metal battery of Example 1 of the present application;

[0021] Figure 4 Functional and safety display diagram of the full solid-state lithium metal battery of Example 1 of the present application;

[0022] Figure 5 Long cycle curve diagram of the solid-state lithium metal battery of Comparative Example 1.

[0023] In the figure: 1, metal negative electrode sheet, 2, solid-state electrolyte, 3, composite cathode sheet, 4, adhesive layer, 5, current collector.

[0024] The purpose realization, functional characteristics and advantages of the present application will be further described in combination with the embodiments and with reference to the drawings. DETAILED DESCRIPTION

[0025] The specific embodiments of the present application will be described in detail below in combination with the drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0026] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples are all conventional biochemical reagents unless otherwise specified; the experimental methods used are all conventional methods unless otherwise specified.

[0027] The dynamic supramolecular ionic conductive elastomer involved in the present application can be obtained by compounding a dynamic supramolecular elastomer and an electrolyte salt, wherein the dynamic supramolecular elastomer can be prepared by polyaddition reaction of polyester / polyether type bifunctional monomer, diisocyanate monomer, anhydrous solvent, chain extender and catalyst. The dynamic supramolecular ionic conductive elastomer has high ionic conductivity, wide electrochemical window, high ionic transference number, high strength, excellent toughness and good interface stability with metal negative electrode. The specific preparation method can refer to the journal "Phase-Locked constructing dynamic supramolecular ionic conductive elastomers with superior toughness, autonomous self-healing and recyclability", Jing Chen, Research Square, published on December 10, 2021, or refer to the Chinese patent with application number 2021116838324.

[0028] The present application uses dynamic supramolecular ionic conductive elastomer as polymer solid-state electrolyte, and uses dynamic supramolecular ionic conductive elastomer as the binder of positive electrode particles. By using the structural reversibility of dynamic supramolecular ionic conductive elastomer, the binder and the solid-state electrolyte can construct integrated positive electrode / electrolyte structure under the action of dynamic exchange and recombination. The formed solid-state metal battery can meet the needs of various energy storage fields such as electric vehicles, flexible electronic products, aerospace, etc.

[0029] In order to enable those skilled in the art to better understand and implement the technical solutions of the present application, the present application will be further described in detail through specific examples.

[0030] Example 1

[0031] As shown in Figure 1 A solid-state metal battery with integrated positive electrode / electrolyte structure is provided, which includes a basic battery unit, the basic battery unit includes a composite positive electrode sheet 3, a solid-state electrolyte 2 and a metal negative electrode sheet 1 stacked in sequence, the material of the solid-state electrolyte 2 is dynamic supramolecular ionic conductive elastomer, and the metal negative electrode sheet 1 is lithium metal, sodium metal, potassium metal, magnesium metal or calcium metal.

[0032] The composite positive electrode sheet 3 comprises a current collector 5 made of aluminum foil or carbon-coated aluminum foil, and a bonding layer 4 coated on the current collector 5, and the composite positive electrode sheet 3 is attached to the solid-state electrolyte 2 through the bonding layer 4, and the bonding layer 4 adheres the positive electrode particles and the conductive agent doped therein to the current collector 5 by using a dynamic supramolecular ion conductive elastomer as a bonding agent.

[0033] The dynamic supramolecular ion conductive elastomer used for the solid-state electrolyte 2 and the bonding layer 4 is composed of a dynamic supramolecular elastomer as a polymer matrix and an electrolyte salt, wherein the electrolyte salt is a lithium salt, a sodium salt, a potassium salt, a zinc salt, a magnesium salt, or a calcium salt, and the electrolyte salt accounts for 5% to 70% of the mass of the dynamic supramolecular elastomer.

[0034] In actual application, the basic battery unit is encapsulated by a battery encapsulation machine to form a solid-state metal battery in the form of a button cell or a soft package, and according to different requirements, the solid-state metal battery encapsulates one, two or more layers of basic battery units, and the two or more layers of basic battery units are electrically connected in series or parallel.

[0035] In a specific implementation, in the bonding layer 4, the mass ratio of the positive electrode particles, the conductive agent, and the dynamic supramolecular ion conductive elastomer is 2:1:7-8:1:1, and in the preparation of the dynamic supramolecular ion conductive elastomer, the positive electrode particles and the conductive agent are doped therein, and finally polymerized to form the bonding layer 4. Among them: the positive electrode particles are one or more of lithium cobaltate, lithium iron phosphate, lithium manganate, lithium titanate, nickel cobalt manganese, sodium vanadium fluorophosphate, Prussian blue, and potassium vanadium fluorophosphate; the conductive agent is one or more of super-p, acetylene black, carbon nanotube, and graphene.

[0036] In another specific implementation, the thickness of the solid-state electrolyte 2 is 1 μm to 1 mm, and is preferably less than 100 μm; and the coating thickness of the bonding layer 4 is less than the thickness of the solid-state electrolyte 2, and is preferably less than 30 μm.

[0037] Example 2

[0038] The application provides a preparation method of a solid-state metal battery with an integrated positive electrode / electrolyte structure, which specifically comprises the following steps:

[0039] First step: Preparation of dynamic supramolecular elastomer. Take 1 mmol of polytetramethylene ether glycol into a Schlenk flask (keep nitrogen or argon atmosphere in the flask), heat to 120 °C, vacuum and gas circulation for 3-5 times to remove residual moisture in the Schlenk flask, cool to 65 °C; dissolve 2.1 mmol of dicyclohexyl methane diisocyanate in a certain amount of anhydrous solvent N,N-dimethylformamide, mix well and then add to the polytetramethylene ether glycol, followed by adding 0.03 mol of catalyst diisobutyl tin dilaurate, stir at 65 °C for 1 h; heat to 80 °C, add 0.7 mmol of 2,2'-dithiodiethanol and 0.3 mmol of 2-ureido-4[1H]pyrimidinone anhydrous dimethyl sulfoxide solution to the above reaction, continue stirring at 80 °C for 9 h, then add a certain amount of methanol and stir for 30 min to ensure that all the isocyanate functional groups are completely reacted; pour the reaction product into a glass culture dish or a polytetrafluoroethylene mold, remove a large amount of solvent in a 60 °C air oven, then put it into a vacuum drying oven at 70 °C for 48 h to remove the residual solvent, and obtain the dynamic supramolecular elastomer.

[0040] Second step: Preparation of precursor solution of dynamic supramolecular ion conductive elastomer. Take 1 g of dynamic supramolecular elastomer and 350 mg of lithium bis(trifluoromethylsulfonyl)imide, dissolve in 30 mL of anhydrous tetrahydrofuran, continue to stir for 24 h to form a transparent colorless homogeneous solution. The dynamic supramolecular ion conductive elastomer precursor solution is divided into two parts, and one of them is used in the following third and fourth steps.

[0041] Third step: Preparation of composite cathode. Lithium iron phosphate cathode particles, super-p and dynamic supramolecular ion conductive elastomer precursor solution are dissolved in a certain volume of anhydrous N-methyl pyrrolidone according to the solute mass ratio of 7:2:1, ball milled for 4 h to form a uniformly dispersed slurry, which is coated on the current collector (aluminum foil or carbon-coated aluminum foil) by spin coating, blade coating and other processes, dried, and cut into pieces to form a composite cathode sheet or a self-supporting composite cathode sheet. In this step, the dynamic supramolecular ion conductive elastomer formed by coating the precursor solution and volatilizing the solvent is used as the binder for lithium iron phosphate cathode particles.

[0042] Fourth step: preparation of the full solid-state lithium metal battery with integrated positive electrode / thin solid-state electrolyte structure. A certain amount of precursor solution is coated on the adhesive layer of the composite positive electrode sheet and the surface of the lithium metal negative electrode sheet by spin coating, blade coating and other processes. After the solvent is completely volatilized, a thin dynamic supramolecular ion conductive elastomer film (also known as a dynamic supramolecular electrolyte film) is formed on the surface of the composite positive electrode sheet and the lithium metal negative electrode sheet. Then the composite positive electrode sheet and the lithium metal negative electrode sheet coated with the electrolyte film are attached together with the coated surface as the attachment surface. The solid-state electrolyte obtained after attachment is composed of two electrolyte films on the composite positive electrode sheet and the lithium metal negative electrode sheet, with a total thickness of 11 um. Finally, the battery is packaged by a battery packaging machine. Under the reversible conditions of the dynamic supramolecular structure, a soft-pack full solid-state lithium metal battery with integrated positive electrode / thin electrolyte structure is formed. In this step, the dynamic supramolecular ion conductive elastomer formed after coating the precursor solution and volatilizing the solvent is used as the solid-state electrolyte of the solid-state metal battery.

[0043] In the above third and fourth steps, the composite positive electrode sheet is coated on the same side, which is the attachment surface attached to the lithium metal negative electrode sheet. After attachment, based on the reversibility of the dynamic supramolecular ion conductive elastomer, the adhesive and the solid-state electrolyte form an integrated positive electrode / electrolyte structure under the action of dynamic exchange and recombination.

[0044] From Figure 1 It can be seen that in the solid-state lithium metal battery prepared in Example 1, the solid-state electrolyte and the adhesive layer form an integrated positive electrode / electrolyte structure under the action of dynamic exchange and recombination, and the solid-state electrolyte is in close contact with the lithium metal negative electrode; from Figure 2 It can be seen that the solid-state lithium metal battery prepared in Example 1 can be stably cycled for more than 300 cycles, and the capacity retention rate can reach 80%, and the coulombic efficiency can reach more than 99%; from Figure 3 It can be seen that the soft-pack battery prepared in Example 1 based on the dynamic supramolecular ion conductive elastomer can normally light the LED lamp, and can still work normally under the environment of folding, rolling, puncturing, breaking and the like, indicating that the battery has very high safety.

[0045] In order to explore the influence of the dynamic supramolecular ion conductive elastomer on the battery performance, Comparative Example 1 is proposed according to the same preparation method and process parameters as Example 2, which only uses PVDF material to replace the dynamic supramolecular ion conductive elastomer (DSICE) in the present application as the adhesive, and the solid-state electrolyte still uses the dynamic supramolecular ion conductive elastomer. Its electrochemical performance test results are shown in Figure 5 It can be seen that the capacity of this battery is significantly lower than that of the dynamic supramolecular ion conductive elastomer as the adhesive.

[0046] Although the specific embodiments of the present application have been described above, it is understood by those skilled in the art that these are merely illustrative and various changes or modifications can be made to the present embodiments without departing from the principles and the spirit of the present application, and the scope of protection of the present application is defined only by the appended claims.

Claims

1. A solid-state metal battery with an integrated positive electrode / electrolyte structure, characterized in that, It includes a basic battery cell, which comprises a composite positive electrode, a solid electrolyte, and a metal negative electrode stacked sequentially, wherein the solid electrolyte is made of a dynamic supramolecular ion-conducting elastomer. The composite positive electrode includes a current collector and an adhesive layer coated on the current collector. The composite positive electrode is bonded to the solid electrolyte through the adhesive layer. The adhesive layer includes an adhesive and positive electrode particles and a conductive agent doped in the adhesive. The adhesive is made of a dynamic supramolecular ion conductive elastomer. The dynamic supramolecular ionic conductive elastomers used for the solid electrolyte and the adhesive layer are both formed by combining the dynamic supramolecular elastomer as a polymer matrix with the electrolyte salt. The dynamic supramolecular elastomer is prepared by a polyaddition reaction of polyester / polyether type bifunctional monomer, diisocyanate monomer, anhydrous solvent, chain extender and catalyst. In the adhesive layer, the mass ratio of positive electrode particles, conductive agent and dynamic supramolecular ionic conductive elastomer is 2:1:7~8:1:1; the thickness of the solid electrolyte is 1 μm ~ 1 mm; the electrolyte salt is lithium salt, sodium salt, potassium salt, zinc salt, magnesium salt or calcium salt, and the electrolyte salt accounts for 5%~70% of the mass of the dynamic supramolecular elastomer.

2. The solid-state metal battery with an integrated positive electrode / electrolyte structure according to claim 1, characterized in that, The positive electrode particles are one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, lithium titanate, nickel cobalt manganese, sodium vanadium fluorophosphate, Prussian blue, and potassium vanadium fluorophosphate; the conductive agent is one or more of super-p, acetylene black, carbon nanotubes, and graphene.

3. The solid-state metal battery with an integrated positive electrode / electrolyte structure according to claim 1, characterized in that, The current collector is aluminum foil or carbon-coated aluminum foil.

4. The solid-state metal battery with an integrated positive electrode / electrolyte structure according to claim 1, characterized in that, The metal anode sheet is made of lithium, sodium, potassium, magnesium, or calcium metal.

5. The solid-state metal battery with an integrated positive electrode / electrolyte structure according to any one of claims 1-4, characterized in that, The solid metal battery is a button cell or a pouch cell, and the solid metal battery contains at least one layer of the basic battery cell.

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