An organic-inorganic hybrid microsphere and application thereof as an electrolyte additive in a zinc ion battery

Abstract

The application belongs to the technical field of aqueous zinc ion batteries, and particularly relates to an organic-inorganic hybrid microsphere and application of the organic-inorganic hybrid microsphere as an electrolyte additive in a zinc ion battery. The application provides an organic-inorganic hybrid microsphere as an additive. The organic-inorganic hybrid microsphere is adsorbed on the surface of a zinc negative electrode in situ during a zinc metal deposition process to form a functional protective layer. The functional protective layer can effectively inhibit a hydrogen evolution reaction, induce uniform nucleation of zinc ions, regulate deposition orientation of the zinc negative electrode, and inhibit growth of dendrites of the zinc negative electrode in the aqueous zinc ion battery, so as to improve coulombic efficiency and cycle life of the aqueous zinc ion battery. In the aqueous zinc ion battery, the electrolyte comprising the organic-inorganic hybrid microsphere is matched with a high-performance battery positive electrode material and a zinc negative electrode, which is helpful to accelerate industrialization of the aqueous zinc ion battery.

Description

Technical Field

[0001] This invention belongs to the field of aqueous zinc-ion battery energy technology, specifically relating to an organic-inorganic hybrid microsphere and its application as an electrolyte additive in zinc-ion batteries. Zinc-ion batteries using this electrolyte exhibit long cycle life and high safety. Background Technology

[0002] The information disclosed in the background section is intended only to enhance the understanding of the general background of the invention and is not necessarily to be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art.

[0003] Environmental pollution and the energy crisis have become severe challenges facing all of humanity, forcing us to improve the existing energy structure and develop clean, efficient renewable energy sources and related technologies. The utilization of renewable energy sources such as solar, wind, hydro, nuclear, and biomass energy requires supporting energy storage batteries to achieve stable output; therefore, developing new, efficient, and environmentally friendly energy storage devices is crucial. Aqueous zinc-ion batteries, due to their abundant raw material resources, low price, environmental friendliness, and high energy density, have gained widespread favor among researchers and are considered the best alternative to lithium-ion batteries. However, uneven dissolution and deposition of zinc during cycling leads to rapid zinc dendrite growth, resulting in short cycle life, low coulombic efficiency, and even dendrite growth that can puncture the separator, causing severe internal short circuits, significantly restricting the practical application of zinc batteries. Therefore, reducing zinc dendrite deposition is an important way to effectively improve the electrochemical performance of aqueous zinc-ion batteries. Modifying the electrolyte with additives is an effective method to reduce zinc dendrite growth, significantly improving electrolyte interface properties, playing a vital role in battery coulombic efficiency, increasing cycle life, and regulating zinc ion deposition, and thus possessing undeniable significance. However, the commonly used conventional inorganic electrolyte additives are not ideal in solving dendrite growth. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, the present invention aims to provide a suspension electrolyte with organic-inorganic hybrid microspheres as additives. This electrolyte can effectively improve the electrolyte interface properties and electrodes, reduce the deposition and growth of zinc dendrites, and improve the electrochemical performance of the battery.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] The first objective of this invention is to provide a suspension electrolyte with organic-inorganic hybrid microspheres as additives for use in aqueous zinc-ion batteries.

[0007] This invention first provides an electrolyte additive, which is an organic-inorganic hybrid microsphere; the organic-inorganic hybrid microsphere has a core-shell structure, comprising an inorganic nanoparticle core and an organic polymer shell; the organic-inorganic hybrid microsphere is first modified with 3-(trimethoxysilyl)propyl-2-methyl-2-acrylate to obtain modified particles, and then coated with an organic polymer shell by polymerization reaction.

[0008] The mass ratio of inorganic nanoparticles to (3-(trimethoxysilyl)propyl-2-methyl-2-acrylate) is 1:80.

[0009] The mass ratio of the modified particles to the monomers is 1:4.

[0010] Furthermore, the inorganic nanoparticles are at least one of silicon dioxide, titanium dioxide, aluminum oxide, and nano-calcium carbonate; the monomer forming the organic polymer shell is at least one of tetravinylpyridine, sodium styrene sulfonate, methacrylic acid, acrylamide, and vinylimidazole. Sodium styrene sulfonate is preferred.

[0011] The crosslinking agent used in the polymerization reaction is ethylene glycol dimethacrylate, which accounts for 0.5 wt% to 5 wt% of the monomer mass.

[0012] The inorganic nanoparticles contain at least one of silicon dioxide, titanium dioxide, aluminum oxide, and nano-calcium carbonate, preferably silicon dioxide, and the nanoparticle size is 1 nm to 100 nm.

[0013] The present invention also provides an electrolyte comprising the aforementioned organic-inorganic hybrid microspheres and a zinc salt. Further, the electrolyte further comprises an aqueous solvent, which is an electrolyte for use with aqueous zinc ions.

[0014] Further, the zinc salt is at least one selected from zinc acetate, zinc sulfate, zinc trifluoromethanesulfonate, zinc tetrafluoroborate, zinc perchlorate, and zinc chloride. The zinc salt in the electrolyte comprises at least one selected from zinc acetate, zinc sulfate, zinc trifluoromethanesulfonate, zinc tetrafluoroborate, zinc perchlorate, and zinc chloride, preferably zinc trifluoromethanesulfonate or zinc sulfate, with a concentration of 1–5 mol / L, preferably 2 mol / L.

[0015] Furthermore, the concentration of the organic-inorganic hybrid microspheres in the electrolyte is 0.05-0.3 mol / L. Preferably, the concentration is 0.2 mol / L.

[0016] The concentration of the additive in the electrolyte in this invention shall not exceed 0.5 mol / L, otherwise precipitation will form, causing blockage of the positive and negative electrode reaction areas and reducing battery performance; the concentration of the additive in the electrolyte shall not be less than 0.05 mol / L, otherwise an effective negative electrode protective layer cannot be formed, reducing the effect.

[0017] A second objective of this invention is to provide a method for preparing the suspension electrolyte with organic-inorganic hybrid microspheres as an additive, as described in the first objective. The electrolyte is prepared by dissolving a soluble zinc salt and the organic-inorganic hybrid microsphere additive in an aqueous solution according to the proportions mentioned above.

[0018] A third objective of this invention is to provide an aqueous zinc-ion battery using an organic-inorganic hybrid microsphere as an additive in a suspension electrolyte as described in the first and second objectives, the aqueous zinc-ion battery comprising a positive electrode, a negative electrode, and an electrolyte; the positive and negative electrodes are treated zinc plates.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention provides an organic-inorganic hybrid microsphere, which, as an electrolyte additive, adsorbs onto the zinc anode surface during zinc metal deposition to form a functionalized protective layer in situ. This functionalized protective layer effectively inhibits hydrogen evolution reaction, induces uniform zinc ion nucleation, regulates the deposition orientation of the zinc anode, and suppresses the growth of zinc anode dendrites in aqueous zinc-ion batteries, thereby improving the coulombic efficiency and cycle life of aqueous zinc-ion batteries. In aqueous zinc-ion batteries, the electrolyte containing this organic-inorganic hybrid microsphere, combined with high-performance battery cathode materials and zinc anodes, helps to accelerate the industrialization of aqueous zinc-ion batteries. Attached Figure Description

[0021] Figure 1 SEM image of the prepared organic-inorganic hybrid microspheres.

[0022] Figure 2 The graphs show the constant current charge-discharge test curves of the zinc-ion batteries in Example 1 and Comparative Example 1.

[0023] Figure 3 The graphs show the constant current charge-discharge test curves of the zinc-ion batteries in Example 2 and Comparative Example 2.

[0024] Figure 4 The image shows the SEM image of the zinc negative electrode of the zinc-ion battery in Example 1 after 100 cycles.

[0025] Figure 5 The image shows the SEM image of the zinc anode of the zinc-ion battery in Comparative Example 1 after 100 cycles. Detailed Implementation

[0026] The present invention will be described in detail below with reference to specific embodiments, but this does not limit the scope of the invention. It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0027] Unless otherwise specified in the examples, preparation was carried out under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products, and all quantities mentioned in the following examples are parts by weight.

[0028] Example 1

[0029] (1) Preparation of inorganic-organic hybrid microspheres:

[0030] 0.5 g of silica inorganic nanoparticles (50 nm) and 40 g of excess MPS (3-(trimethoxysilyl)propyl-2-methyl-2-acrylate) were mixed and stirred for 24 hours. After washing and drying, the modified SiO2-MPS inorganic nanoparticles were obtained.

[0031] 0.2 g of SiO2-MPS inorganic nanoparticles, 0.8 g of sodium styrene sulfonate monomer, and 0.02 g of ethylene glycol dimethacrylate crosslinking agent were dispersed in 80 mL of acetonitrile and heated to allow free radical polymerization to form a polymer layer on the SiO2 surface. After centrifugation, washing, and drying, the inorganic-organic hybrid microspheres of the present invention were obtained.

[0032] (2) Electrolyte preparation:

[0033] Zinc sulfate electrolyte: Weigh 2.88 g of zinc sulfate (containing heptahydrate) and dissolve it in deionized water to prepare a 2 mol / L zinc sulfate solution. Mix thoroughly until a clear, colorless electrolyte is obtained, and prepare several equal portions.

[0034] Take a zinc sulfate solution and add the above-mentioned polar-inorganic hybrid microspheres. The concentration of this additive in the electrolyte is 0.1 mol / L. Then, place the electrolyte in an ultrasonic machine and sonicate for 30 minutes to promote uniform dispersion of the additive, finally obtaining an aqueous zinc-ion battery electrolyte.

[0035] (3) Zinc-ion battery installation:

[0036] A 15mm diameter, 100μm thick zinc foil, ultrasonically cleaned with acetone and ethanol for 10 minutes each, was used as the negative electrode. A 19mm diameter glass fiber was selected as the separator. The batteries were placed in the following order: button cell negative electrode shell, spring contact, gasket, negative electrode, glass fiber, positive electrode, and button cell positive electrode shell. It is particularly important that 200μm of the electrolyte solution described above be evenly dropped onto the glass fiber in each battery.

[0037] Example 2

[0038] (1) Electrolyte preparation:

[0039] Zinc trifluoromethanesulfonate electrolyte: Weigh 2.18 g of zinc trifluoromethanesulfonate and dissolve it in deionized water to prepare a 2 mol / L zinc trifluoromethanesulfonate solution. Mix thoroughly until a clear, colorless electrolyte is obtained, and prepare several equal portions.

[0040] A zinc trifluoromethanesulfonate solution was taken and added to the polar-inorganic hybrid microspheres prepared in Example 1. The concentration of this additive in the electrolyte was 0.1 mol / L. The electrolyte was then sonicated for 30 minutes to promote uniform dispersion of the additive, and finally an aqueous zinc-ion battery electrolyte was obtained.

[0041] Install the zinc-ion battery according to step (3) in Example 1.

[0042] Comparative Example 1

[0043] Zinc sulfate electrolyte: Weigh 2.88 g of zinc sulfate (containing heptahydrate) and dissolve it in deionized water to prepare a 2 mol / L zinc sulfate solution. Mix thoroughly until a clear, colorless electrolyte is obtained, and prepare a zinc sulfate standard sample.

[0044] Install the battery according to step (3) in Example 1.

[0045] Comparative Example 2

[0046] Zinc trifluoromethanesulfonate electrolyte: Weigh 2.18 g of zinc trifluoromethanesulfonate and dissolve it in deionized water to prepare a 2 mol / L zinc trifluoromethanesulfonate solution. Mix thoroughly until a clear, colorless electrolyte is obtained, and prepare a zinc trifluoromethanesulfonate standard sample.

[0047] Install the battery according to step (3) in Example 1.

[0048] Battery test

[0049] Install the aqueous zinc-ion battery according to the above steps, let the battery stand for 2 hours, and then apply 0.5 mA / cm. -2 The current density was used to perform charge and discharge tests.

[0050] Test results are as follows Figure 1 and Figure 2 Batteries prepared using zinc trifluoromethanesulfonate standard and zinc sulfate standard electrolytes were also operated at 0.5 mA / cm. -2 Charge-discharge tests were conducted at a current density of 0.5 mA / cm², but the battery life was only about 60 hours. A suspension electrolyte containing zinc trifluoromethanesulfonate, zinc sulfate, and organic-inorganic hybrid microspheres was used. -2Charge and discharge tests were conducted at the specified current density, and the battery life reached approximately 1000 hours.

[0051] Characterization test

[0052] After testing, the battery was disassembled, the negative electrode was removed, and the electrode was cleaned with deionized water and ethanol before being photographed using a scanning electron microscope (SEM).

[0053] Test results are as follows Figure 3 and Figure 4 SEM images of the battery anode prepared with zinc sulfate standard electrolyte showed obvious dendrite growth, with a large number of dendrites in the coating. However, SEM images of the battery anode prepared with an electrolyte using zinc sulfate and organic-inorganic hybrid microspheres showed that the coating exhibited a dendrite-free and dense reaction morphology.

[0054] Experimental results

[0055] Tests have shown that the aqueous zinc-ion battery electrolyte containing the above-mentioned organic-inorganic hybrid microsphere additive can effectively inhibit dendrite growth on the zinc anode surface and improve the cycle stability of zinc-ion batteries.

[0056] The innovation of this invention lies in the fact that the addition of organic-inorganic hybrid microsphere additives can form a zinc negative electrode protective layer during battery cycling, thereby effectively inhibiting zinc dendrite growth, improving battery coulombic efficiency and cycle stability, and significantly extending battery cycle life. The additives used are present in small quantities, environmentally friendly and harmless, and offer certain advantages for battery safety.

[0057] The constant current charge-discharge performance tests of each embodiment and comparative example are shown in Table 1.

[0058] Table 1. Constant current charge-discharge test results for each embodiment and comparative example.

[0059] Zinc-ion batteries Number of cycles Cycle time Example 1 524 1048 Example 2 490 960 Comparative Example 1 33 66 Comparative Example 2 29 58

[0060] The above embodiments of the present invention are merely examples to clearly illustrate the technical solutions of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. An additive for an aqueous zinc-ion battery electrolyte, characterized in that, The electrolyte additive for the aqueous zinc-ion battery is an organic-inorganic hybrid microsphere; the organic-inorganic hybrid microsphere has a core-shell structure, consisting of an inorganic nanoparticle core and an organic polymer shell; the organic-inorganic hybrid microsphere is first modified by mixing it with inorganic nanoparticles to obtain modified particles, and then coated with an organic polymer shell by polymerization reaction; the inorganic nanoparticles are at least one of silicon dioxide, titanium dioxide, alumina, and nano-calcium carbonate; the monomer forming the organic polymer shell is at least one of tetravinylpyridine, sodium styrene sulfonate, methacrylic acid, acrylamide, and vinylimidazole.

2. The aqueous zinc-ion battery electrolyte additive according to claim 1, characterized in that, The crosslinking agent used in the polymerization reaction is ethylene glycol dimethacrylate, which accounts for 0.5wt% to 5wt% of the monomer mass.

3. The aqueous zinc-ion battery electrolyte additive according to claim 1, characterized in that, The particle size of inorganic nanoparticles ranges from 1 nm to 100 nm.

4. An electrolyte, characterized in that, The electrolyte comprises the aqueous zinc-ion battery electrolyte additive and zinc salt as described in any one of claims 1 to 3.

5. The electrolyte according to claim 4, characterized in that, The zinc salt is at least one of zinc acetate, zinc sulfate, zinc trifluoromethanesulfonate, zinc tetrafluoroborate, zinc perchlorate, and zinc chloride.

6. The electrolyte according to claim 4, characterized in that, The concentration of the organic-inorganic hybrid microspheres in the electrolyte is 0.05-0.3 mol / L.

7. The electrolyte according to claim 4, characterized in that, The concentration of the zinc salt is 1~5 mol / L.

8. The electrolyte according to claim 4, characterized in that, The electrolyte also includes an aqueous solvent.

9. An aqueous zinc-ion battery, characterized in that, Includes the electrolyte according to any one of claims 4 to 8.

10. The aqueous zinc-ion battery according to claim 9, characterized in that, Both the positive and negative electrodes are made of zinc metal.

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