Aqueous zinc ion battery composite electrolyte, preparation method thereof and aqueous zinc ion battery

Abstract

The invention relates to an aqueous zinc ion battery composite electrolyte and a preparation method thereof. The preparation method of the aqueous zinc ion battery composite electrolyte comprises the following steps: uniformly mixing porous silicon dioxide nanosphere particles with a zinc sulfate solution to obtain the aqueous zinc ion battery composite electrolyte, the preparation method of the porous silicon dioxide nanosphere particles comprises the following steps: uniformly mixing a solvent, a surfactant and a catalyst, adding a silicon source substance, and stirring to obtain a nano silicon dioxide suspension solution; and centrifugally washing the nano silicon dioxide suspension, drying the precipitate, grinding, and calcining to obtain the porous silicon dioxide nanosphere particles. According to the water-based zinc ion battery composite electrolyte and the preparation method thereof, the cycle performance and the capacity retention ratio of a water-based zinc ion battery are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aqueous zinc ion batteries, and in particular relates to an aqueous zinc ion battery composite electrolyte and a preparation method thereof, and an aqueous zinc ion battery. Background Art

[0002] Compared with aqueous battery systems, current lithium-ion batteries using organic electrolytes face significant challenges, including limited lithium resources, safety issues, and environmental concerns. In recent years, rechargeable aqueous zinc-ion batteries (ZIBs) have attracted widespread attention as a promising alternative to lithium-ion batteries due to the multiple advantages of zinc metal anodes and aqueous electrolytes.

[0003] Electrolyte optimization is a simple and convenient way to adjust the Zn electrode / electrolyte interface chemistry. By introducing organic solvents with high donor numbers or high acceptor numbers, the Zn 2+ The coordination environment reduces water activity, mitigating H2O-induced side reactions and ultimately extending the cycle life of zinc-ion batteries. Organic additives have proven highly effective in enhancing the performance of zinc-ion batteries, but they also carry certain side effects, such as low conductivity, toxicity, and flammability, which can be fatal. Furthermore, the high viscosity and cost of using large volumes of organic solvents as electrolyte additives have hindered the further development of ZIBs.

[0004] More importantly, for practical zinc anodes, there is still a key challenge that has not been solved, that is, how to maintain the integrity of the zinc surface under strict conditions to ensure long-term cycling performance after the protective layer is damaged. The rupture of the protective layer will expose the fresh Zn anode to the aqueous solution again, which has a potential corrosion risk, which may further induce the formation of dendrites and problems such as hydrogen evolution and corrosion, thereby reducing battery performance. Therefore, a method that can prevent zinc surface cracks, modulate the electrolyte environment and have little effect on the electrolyte conductivity, and has the effect of promoting the long-term cycling of Zn is proposed. 2+ A feasible design strategy for uniform deposition is highly desired for durable and reliable aqueous Zn-ion batteries.

[0005] In view of this, the present invention proposes a new aqueous zinc ion battery electrolyte and a preparation method thereof, and an aqueous zinc ion battery, which has excellent effects and can continuously and stably promote the 2+ Uniform deposition effectively inhibits the formation of zinc dendrites, thereby extending the service life of aqueous zinc ion batteries. Summary of the Invention

[0006] The object of the present invention is to provide a method for preparing a composite electrolyte for an aqueous zinc ion battery, and the preparation method is simple.

[0007] In order to achieve the above objectives, the technical solutions adopted are:

[0008] A method for preparing a composite electrolyte for an aqueous zinc ion battery comprises: uniformly mixing porous silica nanosphere particles with a zinc sulfate solution to obtain the composite electrolyte for an aqueous zinc ion battery;

[0009] The preparation method of the porous silica nanosphere particles is as follows:

[0010] After the solvent, surfactant and catalyst are evenly mixed, a silicon source material is added and stirred to obtain a nano-silicon dioxide suspension solution;

[0011] The nano-silica suspension is centrifuged and washed, and the precipitate is dried, ground, and purified to obtain the porous silica nanosphere particles.

[0012] Furthermore, the concentration of the zinc sulfate solution is 1-3 mol / L;

[0013] The amount of the porous silicon dioxide nanosphere particles used is 0.1-6 wt % of the zinc sulfate solution.

[0014] Furthermore, the amount of the porous silica nanosphere particles is 0.1-3 wt % of the zinc sulfate solution.

[0015] Furthermore, the solvent is water or ethanol;

[0016] The surfactant is cetyltrimethylammonium bromide or polyethylene glycol;

[0017] The catalyst is triethanolamine and sodium salicylate, or triethanolamine and ammonia water;

[0018] The silicon source material is tetraethyl silicate or sodium silicate.

[0019] Furthermore, the washing is: washing with water and washing with alcohol in sequence.

[0020] Furthermore, the drying temperature is 60-80°C and the drying time is 8-12 hours;

[0021] The purification temperature is 400-600° C. and the time is 3-8 hours.

[0022] Another object of the present invention is to provide an aqueous zinc ion battery composite electrolyte prepared by the above-mentioned preparation method, comprising: porous silica nanosphere particles and zinc sulfate solution.

[0023] Another object of the present invention is to provide an aqueous zinc ion battery, the cycle performance and capacity retention rate of which are significantly better than those of existing conventional aqueous zinc ion batteries.

[0024] In order to achieve the above objectives, the technical solutions adopted are:

[0025] An aqueous zinc ion battery adopts the aqueous zinc ion battery composite electrolyte.

[0026] Furthermore, the aqueous zinc ion battery comprises: zinc metal material, intercalation compound, diaphragm, the aqueous zinc ion battery composite electrolyte

[0027] The zinc metal material is one of zinc plate, zinc sheet, zinc foil or three-dimensional zinc foam;

[0028] The intercalation compound is one of a manganese material, a vanadium material, and a Prussian blue analogue;

[0029] The diaphragm is one of glass fiber, qualitative filter paper or polypropylene fiber diaphragm.

[0030] Furthermore, the manganese-based material is MnO2, the vanadium-based material is V2O5, and the Prussian blue analogue is Fe4[Fe(CN)6]3.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention addresses the challenges of current aqueous zinc-ion batteries by employing a novel electrolyte additive for aqueous zinc-ion batteries: a silicon-containing inorganic compound in the form of porous silica nanospheres. By adding this electrolyte additive to a zinc sulfate solution, the composite electrolyte achieves stable properties during use, thereby contributing to the development of superior, safe, and stable aqueous zinc-ion batteries.

[0033] The present invention is assembled into a Zn||Zn symmetrical battery, and the cycle stability test shows that at 10mA·cm -2 It can be stably cycled for 530 h at a current density of 5 mA·cm -2 It can be stably cycled for 3481h at a current density of 0.5mA·cm -2 The electrolyte additive for aqueous zinc ion batteries provided by the present invention can significantly improve the cycle performance of aqueous zinc ion batteries, providing a promising method for preparing high-performance aqueous zinc metal batteries and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a scanning electron microscope characterization image of porous silica nanosphere particles.

[0035] Figure 2 The scanning electron microscope characterization of zinc electrodeposition is shown in FIG. a, which is the Zn anode of Example 1 at 10 mA·cm -2Scanning electron microscopy characterization of the deposition after the next cycle, b is the Zn anode of comparative example 1 at 10 mA cm -2 Scanning electron microscopy characterization of the deposition after the next cycle.

[0036] Figure 3 1 is an X-ray diffraction characterization diagram of the cycle zinc anode using Example 1 and Comparative Example 1.

[0037] Figure 4 The high current (10 mA·cm) of the aqueous zinc ion battery Zn||Zn symmetrical battery of the test electrolyte of Example 2 and the reference electrolyte of Comparative Example 2 -2 )Long-cycle polarization curves.

[0038] Figure 5 The small current (0.5 mA·cm) of the aqueous zinc ion battery Zn||Zn symmetrical battery of the test electrolyte of Example 2 and the reference electrolyte of Comparative Example 2 -2 )Long-cycle polarization curves.

[0039] Figure 6 This is a long cycle performance diagram of the Zn||V2O5 battery of the aqueous zinc ion battery prepared with the test electrolyte of Example 2 and the reference electrolyte of Comparative Example 2.

[0040] Figure 7 Example 5 is a graph showing the effect of different amounts of porous silica nanosphere particle electrolyte additives on the long cycle performance of aqueous zinc ion symmetric batteries. DETAILED DESCRIPTION

[0041] In order to further illustrate the present invention's aqueous zinc ion battery composite electrolyte and its preparation method, aqueous zinc ion battery, and achieve the intended purpose of the invention, the following, in conjunction with the preferred embodiments, describes in detail the aqueous zinc ion battery composite electrolyte and its preparation method, aqueous zinc ion battery, its specific implementation, structure, features and efficacy proposed in accordance with the present invention. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0042] The following is a detailed description of an aqueous zinc ion battery composite electrolyte, a preparation method thereof, and an aqueous zinc ion battery of the present invention in conjunction with specific embodiments:

[0043] The present invention discloses an aqueous zinc ion battery composite electrolyte, a preparation method thereof, and an aqueous zinc ion battery. A porous silica nanosphere particle electrolyte additive is prepared by a template method. The prepared porous silica nanosphere particle electrolyte additive effectively regulates the zinc ion deposition behavior at the electrode-electrolyte interface and plays a certain protective role on the zinc anode surface. The prepared Zn / / MnO2 full battery has good reversible specific capacity and retention rate and has excellent electrochemical performance. Tests show that the use of the aqueous zinc ion battery electrolyte provided by the present invention can significantly improve the cycle performance and capacity retention rate of the aqueous zinc ion battery, providing a promising method for preparing high-performance aqueous zinc metal batteries.

[0044] The technical solution of the present invention is:

[0045] A method for preparing a composite electrolyte for an aqueous zinc ion battery comprises: uniformly mixing porous silica nanosphere particles with a zinc sulfate solution to obtain the composite electrolyte for an aqueous zinc ion battery;

[0046] The preparation method of the porous silica nanosphere particles is as follows:

[0047] After the solvent, surfactant and catalyst are evenly mixed, a silicon source material is added and stirred to obtain a nano-silicon dioxide suspension solution;

[0048] The nano-silica suspension is centrifuged and washed, and the precipitate is dried, ground, and purified to obtain the porous silica nanosphere particles.

[0049] In the above technical solution, porous silica nanosphere particles are used as an electrolyte additive for aqueous zinc ion batteries. The additive changes the solvation structure of zinc ions in the electrolyte, reduces the activity of water at the electrolyte / electrode interface, reduces the occurrence of side reactions caused by inhibiting water, constructs zinc ion transmission channels, and continuously and stably promotes the absorption of Zn 2+ Uniform deposition effectively inhibits the formation of zinc dendrites, thereby extending the service life of aqueous zinc ion batteries.

[0050] In the above-mentioned technical solution, the prepared porous silica nanosphere particles are spherical, and the preparation method of this kind of silica is commonly used in drug-loaded silica, that is, in the medical field. The present invention uses it in aqueous zinc-ion batteries. The porous silica nanospheres are used as zinc-ion battery electrolyte additives. Their spherical morphology is conducive to uniform dispersion and construction of a three-dimensional conductive network, thereby enhancing electron transmission efficiency. The high specific surface area and mesoporous structure improve the wettability of the electrolyte, and the distribution of water molecules is regulated by surface hydroxyl adsorption to inhibit the growth of zinc dendrites. The internal multi-level pores optimize the ion transmission path, promote desolvation and homogenize the electric field distribution, and reduce the deposition overpotential. Compared with traditional additives, it has both the functions of conductive network construction and ion flux regulation, and forms an interdisciplinary collaborative advantage with the design logic of porous sustained release and spherical enhanced compatibility in the field of drug loading.

[0051] Preferably, the concentration of the zinc sulfate solution is 1-3 mol / L;

[0052] The amount of the porous silicon dioxide nanosphere particles used is 0.1-6 wt % of the zinc sulfate solution.

[0053] Preferably, the amount of the porous silica nanosphere particles is 0.1-3 wt % of the zinc sulfate solution.

[0054] Preferably, the solvent is water or ethanol;

[0055] The surfactant is cetyltrimethylammonium bromide or polyethylene glycol;

[0056] The catalyst is triethanolamine and sodium salicylate, or triethanolamine and ammonia water;

[0057] The silicon source material is tetraethyl silicate or sodium silicate.

[0058] Further preferably, the surfactant is cetyltrimethylammonium bromide, the catalyst is triethanolamine and sodium salicylate, the silicon source is tetraethyl silicate, and the mass ratio of cetyltrimethylammonium bromide, triethanolamine, sodium salicylate, and tetraethyl silicate is 0.5-1g:0.1-0.3g:0.2-0.5g:4-12ml.

[0059] Preferably, the washing is: water washing and alcohol washing in sequence.

[0060] Preferably, the drying temperature is 60-80°C and the drying time is 8-12 hours;

[0061] The purification temperature is 400-600° C. and the time is 3-8 hours.

[0062] A composite electrolyte for an aqueous zinc ion battery is prepared by the above-mentioned preparation method and comprises porous silicon dioxide nanosphere particles and a zinc sulfate solution.

[0063] An aqueous zinc ion battery adopts the aqueous zinc ion battery composite electrolyte.

[0064] Preferably, the aqueous zinc ion battery comprises: a zinc metal material, an intercalation compound, a separator, and the above-mentioned aqueous zinc ion battery composite electrolyte. The zinc metal material is used as the negative electrode, the intercalation compound is used as the positive electrode, and the separator is used to separate the positive and negative electrodes.

[0065] The zinc metal material is one of zinc plate, zinc sheet, zinc foil or three-dimensional zinc foam;

[0066] The intercalation compound is one of a manganese material, a vanadium material, and a Prussian blue analogue;

[0067] The diaphragm is one of glass fiber, qualitative filter paper or polypropylene fiber diaphragm.

[0068] Further preferably, the manganese-based material is MnO2, the vanadium-based material is V2O5, and the Prussian blue analogue is Fe4[Fe(CN)6]3.

[0069] Example 1.

[0070] The specific steps are as follows:

[0071] (1) Using magnetic stirring, 50 ml of deionized water and 0.136 g of triethanolamine were mixed and stirred, and then 0.760 g of hexadecyltrimethylammonium bromide and 0.336 g of sodium salicylate were added and stirred, and then 8 ml of tetraethyl silicate was added and stirred to obtain a silica suspension solution.

[0072] (2) After the silica suspension solution is centrifuged and washed (using deionized water and ethanol as detergents in sequence), the precipitate is dried at 80°C for 8 hours, fully ground, and then placed in a muffle furnace for purification at 550°C for 5.5 hours to obtain porous silica nanosphere particles.

[0073] (3) A composite electrolyte is prepared by using porous silica nanosphere particles and 2 mol / L zinc sulfate solution. Specifically:

[0074] At room temperature, 29.47 g of zinc sulfate heptahydrate was added to 30 ml of deionized water and ultrasonicated for 10 min to completely disperse it until it became a transparent, colorless and transparent electrolyte. It was then transferred to a 50 ml volumetric flask and fixed to volume to obtain a 2 mol / L zinc sulfate heptahydrate solution.

[0075] Subsequently, 1 g of 2 mol / L zinc sulfate solution was added to 0.01 g of porous silica nanosphere particles, and ultrasonicated for 20 minutes to completely disperse them to obtain a modified aqueous zinc ion battery composite electrolyte, referred to as ZS-S.

[0076] Comparative Example 1.

[0077] The specific steps are as follows:

[0078] At room temperature, 29.47 g of zinc sulfate heptahydrate was added to 30 ml of deionized water and ultrasonicated for 10 min to completely disperse it until it became a transparent, colorless, and transparent electrolyte. The solution was then transferred to a 50 ml volumetric flask and fixed to volume to obtain a 2 mol / L zinc sulfate heptahydrate solution, which was used as the electrolyte, referred to as ZS.

[0079] Example 2.

[0080] Example 1 and Comparative Example 1 were tested.

[0081] (1) Scanning electron microscopy characterization of porous silica nanoparticles

[0082] The porous silica nanosphere particles prepared in Example 1 were evenly dispersed in an ethanol solution in an appropriate amount, and then an appropriate amount of the ethanol solution was dropped onto a silicon wafer to make it evenly dispersed. After it dried, the porous silica nanosphere particles were tested by scanning electron microscopy.

[0083] The morphology of the porous silica nanosphere particles prepared in Example 1 is as follows Figure 1 As shown, the uniform porous spheres can make zinc ions evenly deposited on the surface of zinc, thereby improving the cycle performance of the new ion battery.

[0084] (2) Scanning electron microscopy characterization of zinc electrodeposition

[0085] Verify the effect of porous silica nanosphere particles on inducing uniform deposition of zinc ions.

[0086] Method: The composite electrolyte of Example 1 and the electrolyte of Comparative Example 1 were assembled into zinc ion symmetrical batteries, and the -2 After one hour of deposition under a current density of , the battery was disassembled and its negative electrode zinc foil was taken for scanning electron microscopy characterization test of zinc ion battery deposition.

[0087] Results: As Figure 2 shown.

[0088] The symmetrical battery assembled with the electrolyte of Comparative Example 1 was -2 The deposition morphology after cycling at a current density of Figure 2 As shown in (a), the zinc deposit structure is loose with many disordered clusters and corrosion pits, which may aggravate the corrosion reaction and the accumulation of byproducts, eventually leading to battery failure.

[0089] The symmetrical battery assembled with the composite electrolyte of Example 1 was -2 The deposition morphology after cycling at a current density of Figure 2 As shown in (b), due to the presence of the formed SEI protective layer (porous silica nanosphere particles can in situ form a zinc-philic protective SEI layer, guiding the uniform nucleation of Zn and inhibiting the occurrence of side reactions), zinc is deposited in a layered stacking morphology parallel to the basal plane without obvious dendrites.

[0090] (3) X-ray diffraction characterization

[0091] Method: The composite electrolyte of Example 1 and the electrolyte of Comparative Example 1 were assembled into symmetrical cells, and the electrolyte was charged at 10 mA·cm -2 After 1 h of reaction under current, X-ray diffraction characterization of zinc deposition was performed.

[0092] Results: As Figure 3 shown.

[0093] Depend on Figure 3 The X-ray diffraction characterization of zinc deposition in the ZS electrolyte also shows that all characteristic peaks match well with the standard phase of metallic zinc (PDF#65-3358), and the Zn(101) peak intensity is the highest, indicating that under Comparative Example 1, the main crystal plane of zinc ion deposition is the Zn(101) crystal plane perpendicular to the basal plane, and the formation of the by-product Zn4SO4(OH)6·6H2O is observed.

[0094] Figure 3 For ZS-S electrolyte at 10 mA·cm -2 X-ray diffraction characterization of zinc deposition after 1 hour of reaction under current shows that all characteristic peaks match well with the standard phase of metallic zinc (PDF#65-3358), and the Zn(002) peak intensity of ZS-S is significantly higher than that of ZS, indicating that under Example 1, the main crystal plane of zinc ion deposition is the Zn(002) crystal plane parallel to the basal plane. At the same time, it is observed that the peak of the ZS-S by-product (Zn4SO4(OH)6·6H2O) is significantly lower than the peak of the by-product produced by ZS, and the peak produced by ZS is almost negligible.

[0095] (4) Long cycle performance test at different current densities

[0096] Verify the modification of the cycling performance of zinc ion batteries by the addition of porous silica nanosphere particles.

[0097] Method: Take appropriate amounts of the composite electrolyte of Example 1 and the electrolyte of Comparative Example 1 and assemble them into zinc ion symmetrical batteries. -2 , 0.5mA·cm -2 ) cycle test.

[0098] Results: As Figure 4 、 Figure 5 shown.

[0099] The symmetrical battery loaded with the electrolyte of Comparative Example 1 has a large and small current density (10mA·cm -2 , 0.5mA·cm -2 ) The performance diagram of the cycle test is as follows Figure 4 、 Figure 5 As shown. ZS at a current density of 10 mA·cm -2 The cycle time is only more than 90 hours; ZS has a current density of 0.5 mA·cm -2 The time cycle is only 379 hours.

[0100] The symmetrical battery loaded with the composite electrolyte of Example 1 has a large and small current density (10mA·cm -2 , 0.5mA·cm -2 ) The performance diagram of the cycle test is as follows Figure 4 、 Figure 5 As shown in Figure 2, the symmetrical battery (ZS-S) prepared using the composite electrolyte is far superior to the zinc sulfate heptahydrate electrolyte (ZS). ZS has a current density of 10 mA cm -2 The cycle time of ZS-S is only more than 90 hours at the same current density, while that of ZS-S can reach 530 hours at the same current density. -2 The cycle time of ZS-S is only 379 hours at the same current density, while that of ZS-S can reach 4540 hours at the same current density. It can be seen that the cycle performance of symmetric zinc ion batteries can be significantly improved by adding porous silica nanospheres.

[0101] From the above experiments, it can be seen that the porous silica nanoparticle additive can not only induce the in situ formation of a zinc-philic layer containing silicon oxide compounds at the zinc negative electrode, promoting the uniform deposition of zinc ions, but also construct a three-dimensional zinc ion transport network with stable chemical properties through the hierarchical pore design of porous silica nanosphere particles.

[0102] In summary, the above experimental characterizations show that the hydroxyl groups on the surface of the nanoparticles spontaneously attach to the new negative electrode in the electrolyte, generating a continuous zinc-philic layer in situ. This layer has a dual protection mechanism: on the one hand, through dynamic regulation of surface charge, it produces electrostatic repulsion on large zinc particles, preventing their irreversible deposition, thereby inhibiting the formation of dead zinc; on the other hand, the silicon-oxygen network provides a uniform distribution of nucleation sites, reduces the local current density, induces zinc ions to grow in a layered epitaxial mode, and significantly inhibits the formation of dendrites.

[0103] Example 3.

[0104] Aqueous zinc-ion batteries were prepared using porous silica nanospheres as an electrolyte additive for aqueous zinc-ion batteries. The effect of the porous silica nanosphere electrolyte additive on improving the capacity retention and service life of the aqueous zinc-ion battery was tested. The specific steps are as follows:

[0105] (1) At room temperature, 29.47 g of zinc sulfate heptahydrate was added to 30 ml of deionized water and ultrasonicated for 10 min to completely disperse it until it became a transparent, colorless, and transparent electrolyte. The solution was then transferred to a 50 ml volumetric flask and fixed to volume to obtain a 2 mol / L zinc sulfate heptahydrate solution.

[0106] (2) Then, 1 g of 2 mol / L zinc sulfate solution was added to porous silica nanosphere particles (porous silica nanosphere particles prepared in Example 1) with a zinc sulfate solution concentration of 1 wt %, and the particles were completely dispersed by ultrasonic treatment for 20 min to prepare a modified aqueous zinc ion battery composite electrolyte.

[0107] (3) Commercial manganese dioxide was used as the positive electrode material. MnO2 was mixed with SuperP and polyvinylidene fluoride in a mass ratio of 7:2:1, and ground in an agate mortar for 40 minutes. N-methylpyrrolidone was added and ground for another 30 minutes. The mixture was then evenly coated on the surface of a stainless steel mesh with a scraper. The mixture was then placed in a vacuum oven at 80°C and dried for 12 hours. After cooling, the mixture was taken out and cut into pieces for later use.

[0108] The MnO2 cathode material prepared above was used as the positive electrode, zinc foil as the negative electrode, and glass fiber as the separator. 120 μL of the above electrolyte was taken to assemble a CR2032 aqueous zinc ion button-type full battery. The cyclic charge and discharge test was carried out in the blue battery test system with a current density of 0.5Ag. -1 .

[0109] Comparative Example 2.

[0110] Take 120 μL of the electrolyte of Comparative Example 1, use the MnO2 positive electrode material prepared by the same method as Example 3, take zinc foil as the negative electrode, and glass fiber as the separator to assemble a CR2032 type aqueous zinc ion button full battery.

[0111] Example 4.

[0112] The CR2032 aqueous zinc ion button-type full batteries assembled in Example 3 and Comparative Example 2 were subjected to cyclic charge and discharge tests in a blue battery test system. The current density was 0.5Ag -1 .

[0113] The results are as follows Figure 6As shown in the figure, the Zn / / MnO2 full battery using the composite electrolyte (ZS-S in the figure is the modified aqueous zinc ion battery composite electrolyte of Example 3) still has a high reversible capacity of 59.6 mAh / g after 4800 cycles. In contrast, the Zn / / MnO2 full battery using the ZS electrolyte (i.e., the zinc sulfate solution of Comparative Example 2) has a lower reversible specific capacity during the entire cycle. This shows that during the cycle, the addition of porous silica nanosphere particles can reduce the formation of zinc dendrites, reduce capacity loss, and improve the reversibility of zinc deposition / stripping reactions.

[0114] Example 5.

[0115] The specific steps are as follows:

[0116] (1) Using magnetic stirring, 50 ml of deionized water and 0.1 g of triethanolamine were mixed and stirred, and then 0.5 g of hexadecyltrimethylammonium bromide and 0.2 g of sodium salicylate were added and stirred, and then 4 ml of tetraethyl silicate was added and stirred to obtain a silica suspension solution.

[0117] (2) After the silica suspension solution is centrifuged and washed (using deionized water and ethanol as detergents in sequence), the precipitate is dried at 60°C for 12 hours, fully ground, and then placed in a muffle furnace for purification at 400°C for 8 hours to obtain porous silica nanosphere particles.

[0118] (3) At room temperature, 14.74 g of zinc sulfate heptahydrate was added to 30 ml of deionized water and ultrasonicated for 10 min to completely disperse it until it became a transparent, colorless, and transparent electrolyte. The solution was then transferred to a 50 ml volumetric flask and fixed to volume to obtain a 1 mol / L zinc sulfate heptahydrate solution.

[0119] Subsequently, 10 g of 1 mol / L zinc sulfate solution was added, 0.01 g of porous silica nanosphere particles were added, and ultrasonication was performed for 20 minutes to completely disperse the particles, thereby preparing a modified aqueous zinc ion battery composite electrolyte.

[0120] (3) Commercial V2O5 was used as the positive electrode material. 80 mg of V2O5 was mixed with 20 mg of SuperP and 10 mg of polyvinylidene fluoride in a mass ratio of 7:2:1. The mixture was placed in an agate mortar and ground for 40 min. An appropriate amount of N-methylpyrrolidone was added and the mixture was further ground for 30 min. The mixture was then evenly coated on the surface of a stainless steel mesh with a scraper. The mixture was then placed in a vacuum oven at 80 °C and dried for 12 h. After cooling, the mixture was taken out and cut into pieces for later use.

[0121] The V2O5 cathode material prepared above was used as the cathode, the zinc sheet as the anode, and the glass fiber as the separator. 120 μL of the above electrolyte was taken to assemble a CR2032 aqueous zinc ion button-type full battery.

[0122] Example 6.

[0123] The specific steps are as follows:

[0124] (1) Using magnetic stirring, 80 ml of deionized water and 0.3 g of triethanolamine were mixed and stirred, and then 1 g of hexadecyltrimethylammonium bromide and 0.5 g of sodium salicylate were added and stirred, and then 12 ml of tetraethyl silicate was added and stirred to obtain a silica suspension solution.

[0125] (2) After the silica suspension solution is centrifuged and washed (using deionized water and ethanol as detergents in sequence), the precipitate is dried at 70°C for 10 hours, fully ground, and then placed in a muffle furnace for purification at 600°C for 3 hours to obtain porous silica nanosphere particles.

[0126] (3) At room temperature, 44.22 g of zinc sulfate heptahydrate was added to 30 ml of deionized water and ultrasonicated for 20 min to completely disperse it until it became a transparent, colorless, and transparent electrolyte. The electrolyte was then transferred to a 50 ml volumetric flask and fixed to volume to obtain a 3 mol / L zinc sulfate heptahydrate solution.

[0127] Subsequently, 1 g of 3 mol / L zinc sulfate solution was added, 0.03 g of porous silica nanosphere particles were added, and ultrasonication was performed for 20 minutes to completely disperse the particles, thereby preparing a modified aqueous zinc ion battery composite electrolyte.

[0128] (3) A commercial Prussian blue analog Fe4[Fe(CN)6]3 was used as the positive electrode material. 80 mg of Fe4[Fe(CN)6]3 was mixed with SuperP and polyvinylidene fluoride in a mass ratio of 7:2:1, and ground in an agate mortar for 40 min. N-methylpyrrolidone was added and ground for another 30 min. The mixture was then evenly coated on the surface of a stainless steel mesh with a scraper. The mixture was then dried in a vacuum oven at 80 °C for 12 h, cooled, and cut into pieces for later use.

[0129] The Fe4[Fe(CN)6]3 cathode material prepared above was used as the positive electrode, the zinc plate as the negative electrode, and the polypropylene fiber as the separator. 120 μL of the above electrolyte was taken to assemble an aqueous zinc ion button-type full battery.

[0130] Example 7.

[0131] The operating steps of Example 7 are the same as those of Example 1, except that:

[0132] (1) After mixing 50 ml of ethanol and 0.136 g of triethanolamine, 0.760 g of polyethylene glycol and 0.336 g of ammonia water were added and stirred, and then 5 g of sodium silicate was added and stirred to obtain a silica suspension solution.

[0133] Example 8.

[0134] The specific steps are as follows:

[0135] Aqueous zinc-ion batteries were prepared using porous silica nanospheres as an electrolyte additive. The effects of different amounts of porous silica nanosphere electrolyte additive on the long-cycle performance of aqueous zinc-ion symmetric batteries were tested. The specific steps are as follows:

[0136] (1) At room temperature, 29.47 g of zinc sulfate heptahydrate was added to 30 ml of deionized water and ultrasonicated for 10 min to completely disperse it until it became a transparent, colorless, and transparent electrolyte. The solution was then transferred to a 50 ml volumetric flask and fixed to volume to obtain a 2 mol / L zinc sulfate heptahydrate solution.

[0137] (2) Porous silica nanosphere particles (porous silica nanosphere particles prepared in Example 1) with 0.1 wt%, 1 wt%, 2 wt%, 3 wt%, and 6 wt% of the zinc sulfate solution were added to a 2 mol / L zinc sulfate solution, respectively, and the particles were completely dispersed by ultrasonication for 20 min to prepare aqueous zinc ion battery composite electrolytes with different addition amounts. The specific steps are as follows:

[0138] Take 5 portions of 1g 2mol / L zinc sulfate solution, add 0.001g, 0.01g, 0.02g, 0.03g, and 0.06g of porous silica nanosphere particles, respectively, and ultrasonicate for 20 minutes to completely disperse them, thereby preparing aqueous zinc ion battery composite electrolytes with different addition amounts.

[0139] (3) Long cycle performance test at different current densities

[0140] Verify the modification of the cycling performance of zinc ion batteries by the addition of porous silica nanosphere particles.

[0141] Method: Take appropriate amount of the above-mentioned aqueous zinc ion battery composite electrolyte in the amount of 0.1wt%, 1wt%, 2wt%, 3wt%, 6wt% to assemble zinc ion symmetrical battery, and then add the electrolyte at a high current density (10mA·cm -2 ) cycle test.

[0142] Results: As Figure 7 shown.

[0143] The symmetrical battery loaded with the electrolyte of Example 7 was -2 ) The performance diagram of the cycle test is as follows Figure 7 The composite electrolytes with addition amounts of 0.1wt%, 1wt%, 2wt%, 3wt%, and 6wt% have the following characteristics at a current density of 10 mA·cm -2The cycles are 168, 530, 290, 207 and 237 hours respectively; the selected addition amount is 0.1-3wt%, and the optimal addition amount is 1wt%.

[0144] The examples show that when the porous silica nanosphere particles prepared according to the method of the present invention are used as an electrolyte additive for aqueous zinc-ion batteries, the resulting Zn||Zn symmetrical battery exhibits extremely high cycling stability. Scanning electron microscopy analysis of the zinc anode surface morphology also reveals the absence of obvious flaky zinc dendrites, indicating that the porous silica nanosphere additive effectively regulates zinc ion deposition at the electrode-electrolyte interface and provides some protection for the zinc anode surface. The resulting Zn / / MnO2 full battery exhibits excellent reversible specific capacity and retention, demonstrating the excellent electrochemical properties of the material prepared by the present invention.

[0145] The above is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the embodiments of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the embodiments of the present invention are still within the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a composite electrolyte for an aqueous zinc ion battery, characterized in that: The preparation method comprises the following steps: uniformly mixing porous silica nanosphere particles with zinc sulfate solution to obtain the aqueous zinc ion battery composite electrolyte; The preparation method of the porous silica nanosphere particles is as follows: After the solvent, surfactant and catalyst are evenly mixed, a silicon source material is added and stirred to obtain a nano-silicon dioxide suspension solution; The nano-silica suspension is centrifuged and washed, and the precipitate is dried, ground, and purified to obtain the porous silica nanosphere particles.

2. The preparation method according to claim 1, characterized in that The concentration of the zinc sulfate solution is 1-3 mol / L; The amount of the porous silicon dioxide nanosphere particles used is 0.1-6 wt % of the zinc sulfate solution.

3. The preparation method according to claim 2, characterized in that The amount of the porous silicon dioxide nanosphere particles used is 0.1-3 wt % of the zinc sulfate solution.

4. The preparation method according to claim 1, characterized in that The solvent is water or ethanol; The surfactant is cetyltrimethylammonium bromide or polyethylene glycol; The catalyst is triethanolamine and sodium salicylate, or triethanolamine and ammonia water; The silicon source material is tetraethyl silicate or sodium silicate.

5. The preparation method according to claim 1, characterized in that The washing comprises: washing with water and washing with alcohol in sequence.

6. The preparation method according to claim 1, characterized in that The drying temperature is 60-80°C and the drying time is 8-12 hours; The purification temperature is 400-600° C. and the time is 3-8 hours.

7. An aqueous zinc ion battery composite electrolyte, characterized in that The aqueous zinc ion battery electrolyte is prepared by the preparation method according to any one of claims 1 to 6, and comprises porous silica nanosphere particles and zinc sulfate solution.

8. An aqueous zinc ion battery, characterized in that The aqueous zinc ion battery composite electrolyte according to claim 7 is used.

9. The aqueous zinc ion battery according to claim 8, wherein The aqueous zinc ion battery comprises: a zinc metal material, an intercalation compound, a diaphragm, and the aqueous zinc ion battery composite electrolyte according to claim 7; The zinc metal material is one of zinc plate, zinc sheet, zinc foil or three-dimensional zinc foam; The intercalation compound is one of a manganese material, a vanadium material, and a Prussian blue analogue; The diaphragm is one of glass fiber, qualitative filter paper or polypropylene fiber diaphragm.

10. The aqueous zinc ion battery according to claim 9, characterized in that The manganese material is MnO2, the vanadium material is V2O5, and the Prussian blue analogue is Fe4[Fe(CN)6]3.

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