Mesoporous nanoparticle-based aqueous battery composite electrolyte and application thereof

Abstract

The invention relates to an aqueous battery composite electrolyte based on mesoporous nanoparticles and application of the aqueous battery composite electrolyte. The composite electrolyte comprises mesoporous nanoparticles, water, inorganic salt and an additive, the electrolyte is prepared from the following raw materials in percentage by weight: 0.1-5% of mesoporous nanoparticles, 20-65% of inorganic salt, 0-30% of an additive and the balance of water which is supplemented to 100%, wherein the particle size of the mesoporous nano-particles is intensively distributed in a range of 10 to 100 nm, and the pore size is intensively distributed in a range of 2 to 50 nm. Compared with the prior art, the composite electrolyte can effectively solve the problems of dendritic crystal, corrosion, side reaction and the like in an aqueous battery, so that the rate capability and the cycling stability of the battery are remarkably improved. In addition, the preparation method is simple, raw materials are easy to obtain, and the preparation method is suitable for large-scale production. The electrolyte design provided by the invention provides a solution for a high-safety and long-life aqueous battery.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical energy storage, and particularly to a water-based battery composite electrolyte based on mesoporous nanoparticles and its application. Background Art

[0002] Water-based batteries have become a key research direction for large-scale energy storage technologies due to the multiple advantages of using intrinsically safe water-based electrolytes. Taking zinc-based water-based batteries as an example, their zinc anodes have significant theoretical capacity characteristics (volume capacity 5851 mAh / cm 3 , mass capacity 820 mAh / g), low redox potential (-0.762 V vs. SHE), and the characteristics of being assembled in an air atmosphere. In addition, the anode materials (zinc, tin, graphite, zinc oxide) of water-based batteries have high crustal abundance and strong environmental compatibility, further enhancing their industrialization potential. Different from the mechanism in traditional organic systems (such as lithium / sodium-ion batteries) where solvated cations form a stable interfacial layer through desolvation, solvated water molecules in water-based batteries are prone to accumulate at the electrode interface, triggering uncontrollable hydrogen evolution reactions and generating loose by-products. Such by-products not only cannot effectively protect the zinc anode, but will instead exacerbate interfacial corrosion and dendrite growth, leading to rapid decay of battery performance. Although people have begun to use the surface properties of nanoparticles to modify water-based electrolytes, the addition of these reported nanoparticles to the electrolyte often makes the electrolyte form a gel or semi-solid state, which is not conducive to ion desolvation and rapid ion transport, and is not conducive to the fast charge and discharge performance of water-based batteries. At the same time, due to the lack of formation of a stable interface, the cycle life of water-based batteries prepared with these modified electrolytes is still not ideal. For example, Patent CN114497761A discloses a preparation method of a silica organic-aqueous hybrid gel electrolyte, but due to its high addition amount and the high viscosity of the gel electrolyte itself, the cation diffusion rate is reduced, and the charge and discharge polarization is serious. Therefore, developing new electrolytes, regulating the ion solvation structure and interfacial chemistry to inhibit water molecule aggregation and interfacial side reactions, is the core technical difficulty in realizing high-capacity and long-cycle water-based batteries. Summary of the Invention

[0003] The purpose of the present invention is to provide a water-based battery composite electrolyte based on mesoporous nanoparticles and its application, so as to solve the problems of side reactions and unstable interfaces in water-based batteries in water-based electrolytes, and realize high-capacity and long-cycle water-based batteries.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A water-based battery composite electrolyte based on mesoporous nanoparticles, comprising mesoporous nanoparticles, inorganic salts, and water;

[0005] The particle size of the mesoporous nanoparticles is concentrated in the range of 10 - 100 nm, and the pore size is concentrated in the range of 2 - 50 nm.

[0006] Preferably, the aqueous battery composite electrolyte based on mesoporous nanoparticles comprises mesoporous nanoparticles, inorganic salts, water and organic additives;

[0007] The raw material ratio of the electrolyte is calculated by weight percentage, wherein, mesoporous nanoparticles are 0.1-5%, inorganic salts are 20-65%, organic additives are 0-30%, and the balance is water supplemented to 100%.

[0008] More preferably, the organic additives include one or a mixture of water-soluble organic solvents and surfactants.

[0009] Even more preferably, the water-soluble organic solvent is one or a mixture of methanol, ethanol, isopropanol, acetone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, formaldehyde, glucose.

[0010] Even more preferably, the surfactant is one or a mixture of polyvinylpyrrolidone, polyvinyl alcohol, sodium dodecyl sulfate, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride.

[0011] By preferably selecting water-soluble organic solvents and surfactant additives, the high dispersion stability of mesoporous nanoparticles in the aqueous battery composite electrolyte can be ensured. At the same time, the use of these additives can further cooperate with mesoporous nanoparticles to stabilize water in the electrolyte, accelerate the ion desolvation effect, so that the obtained aqueous battery can achieve high energy density, long cycle life and excellent rate performance.

[0012] Preferably, the mesoporous nanoparticles include one or more of mesoporous silica, mesoporous titanium dioxide, mesoporous zinc oxide, mesoporous alumina, mesoporous dopamine, mesoporous metal-organic frameworks.

[0013] Different types of mesoporous nanoparticles are selected according to different systems of aqueous batteries, which can ensure the chemical stability of the electrolyte. Controlling the amount of mesoporous nanoparticles added at 0.1-5% is beneficial to ensuring the good fluidity of the electrolyte, accelerating ion transport. At the same time, due to the mesoporous characteristics of mesoporous nanoparticles, they have a larger specific surface area, which can reduce the dosage and save costs; the particle size of mesoporous nanoparticles is concentrated in the smaller size range of 10-100 nm, which is beneficial to ensuring their good dispersibility, restricting free water in the electrolyte and reducing side reactions of the electrode; the pore size of mesoporous nanoparticles is concentrated in the range of 2-50 nm, which is beneficial to accelerating desolvation, realizing fast ion transport and achieving long battery life.

[0014] Preferably, the inorganic salts include one or a mixture of zinc salts, sodium salts, lithium salts, potassium salts, magnesium salts that are soluble in water.

[0015] Further preferably, the zinc salt is one or a mixture of more than one of zinc sulfate, zinc chloride, zinc acetate, zinc trifluoromethanesulfonate, and zinc perchlorate.

[0016] Further preferably, the sodium salt is one or a mixture of more than one of sodium chloride, sodium bromide, sodium sulfate, sodium trifluoromethanesulfonate, and sodium perchlorate.

[0017] Further preferably, the lithium salt is one or a mixture of more than one of lithium chloride, lithium bromide, lithium sulfate, lithium trifluoromethanesulfonate, and lithium bis(trifluoromethanesulfonyl)imide.

[0018] Further preferably, the potassium salt is one or a mixture of more than one of potassium chloride, potassium bromide, potassium sulfate, potassium fluoride, and potassium carbonate.

[0019] Further preferably, the magnesium salt is one or a mixture of more than one of magnesium chloride, magnesium sulfate, magnesium trifluoromethanesulfonate, and magnesium perchlorate.

[0020] The aqueous electrolyte composite formed by the composite of mesoporous nanoparticles and different inorganic salts can be compatible with different types of aqueous battery electrode materials, ensure the stability of the electrode materials, and achieve the long life of the aqueous battery; moreover, the types of inorganic salts are rich, which is beneficial to reducing the cost of the electrolyte and achieving the low cost of the aqueous battery.

[0021] Preferably, the mesoporous nanoparticles are hollow nanospheres.

[0022] Further preferably, the wall thickness of the mesoporous nanoparticles is 4 - 5 nm.

[0023] Preferably, the surface area of the mesoporous nanoparticles is 400 - 600 m 2 / g, and the pore volume is 0.8 - 1.4 cm 3 / g.

[0024] Preferably, the preparation method of the mesoporous nanoparticles includes the following steps:

[0025] S1: Uniformly disperse the surfactant in the aqueous phase to form a clear and transparent micellar solution;

[0026] S2: Dissolve the nanoparticle precursor in the above micellar solution, and stir and react for a period of time to generate a product;

[0027] S3: Filter, wash, and calcine the product to obtain well-dispersed mesoporous nanoparticles.

[0028] Further preferably, the surfactant in step S1 (i.e., the surfactant for preparing mesoporous nanoparticles) is one or more of P123, P103, F127, F108, cetyltrimethylammonium bromide, PS-PEO-PVP, PS-PEO, and PS-PVP.

[0029] Further preferably, the nanoparticle precursor in step S2 is one or more of tetraethyl orthosilicate, tetrabutyl titanate, dopamine, zinc nitrate, zinc chloride, iron nitrate, iron chloride, and Prussian blue; the reaction time is 2 - 24 h.

[0030] Through the optimization of the surfactant and precursor for preparing mesoporous nanoparticles, the regulation of the particle size distribution and pore size distribution of mesoporous nanoparticles can be achieved, ensuring good dispersibility of mesoporous nanoparticles in the composite electrolyte of aqueous batteries; through the optimization of the reaction time, it is beneficial to realize low-cost manufacturing and reduce the cost of the composite electrolyte of aqueous batteries.

[0031] An application of the above-mentioned composite electrolyte for aqueous batteries based on mesoporous nanoparticles, wherein the composite electrolyte for aqueous batteries based on mesoporous nanoparticles is used in aqueous batteries.

[0032] Preferably, the aqueous battery includes one or more of zinc-based aqueous batteries, sodium-ion aqueous batteries, lithium-ion aqueous batteries, potassium-ion aqueous batteries, and magnesium-ion aqueous batteries.

[0033] A composite electrolyte for aqueous batteries based on mesoporous nanoparticles according to the present invention has the following working principle and characteristics:

[0034] First, as an ion carrier, the surface functional groups of mesoporous nanoparticles can interact with cations in the electrolyte, change the cation solvation structure, and enhance the ionic conductivity and diffusion rate, realizing fast charge and discharge operation of the battery.

[0035] Second, the large specific surface area and ordered pore structure of mesoporous nanoparticles confine water molecules inside the pores, reducing the water activity and weakening its corrosion of the negative and positive electrodes, ensuring the service life of the aqueous battery.

[0036] Third, as an ion-carrying mesoporous material, it migrates to the electrode surface under the action of an electric field to form a solid interface layer, breaking the agglomeration of interfacial water, reducing the decomposition and side reactions of the electrolyte, and further improving the battery life.

[0037] In the prior art, there are problems such as poor electrolyte stability, poor kinetic performance, and poor cycle stability in aqueous electrolytes.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The present invention provides a composite aqueous electrolyte based on mesoporous nanoparticles for aqueous batteries, which can achieve high capacity, high reversibility, high Coulomb efficiency, fast charge-discharge performance and long life for aqueous batteries; moreover, the obtained composite aqueous electrolyte for aqueous batteries has low cost and can effectively reduce the battery cost.

[0040] 2. The composite electrolyte of the present invention can effectively solve problems such as dendrites, corrosion and side reactions in aqueous batteries, thus significantly improving the rate performance and cycle stability of the batteries. In addition, the preparation method provided by the present invention is simple, the raw materials are easy to obtain, and it is suitable for large-scale production. The electrolyte provided by the present invention provides a solution for high-safety and long-life aqueous batteries.

[0041] 3. The preparation process of the mesoporous nanoparticle aqueous electrolyte of the present invention is simple and reliable, with appropriate cost and good repeatability, and has broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the components of the composite aqueous electrolyte for aqueous batteries based on mesoporous nanoparticles of the present invention.

[0043] Figure 2 It is a schematic diagram of the preparation and action mechanism of the composite electrolyte of mesoporous nanoparticles in Example 1.

[0044] Figure 3 It is a transmission electron microscope image of the mesoporous nanoparticles in Example 1.

[0045] Figure 4 It is the nitrogen adsorption-desorption curve and pore size distribution of the mesoporous nanoparticles in Example 1.

[0046] Figure 5 It is the viscosity and ionic conductivity of the composite electrolyte in Example 1.

[0047] Figure 6 It is the desolvation activation energy of the composite electrolyte in Example 1 and the ordinary electrolyte in Comparative Example 1.

[0048] Figure 7 It is a scanning electron microscope image of the zinc negative electrode after working in the composite electrolyte in Example 1.

[0049] Figure 8 It is a comparison of the long cycle performance of the Zn / / Zn symmetric aqueous batteries in Example 1 and Comparative Examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0050] The present invention will be described in detail below with reference to the drawings and specific examples. This example is implemented on the premise of the technical solution of the present invention, and the detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following examples.

[0051] A composite aqueous electrolyte for a water-based battery based on mesoporous nanoparticles, as Figure 1 shown, comprising mesoporous nanoparticles, inorganic salts, water and organic additives; the particle size of the mesoporous nanoparticles is concentrated in the range of 10-100 nm, and the pore size is concentrated in the range of 2-50 nm. The raw material ratio of the electrolyte is calculated by weight percentage, wherein, 0.1-5% of mesoporous nanoparticles, 20-65% of inorganic salts, 0-30% of additives, and the balance is water supplemented to 100%.

[0052] The following is a detailed description in conjunction with specific embodiments.

[0053] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0054] Example 1

[0055] A composite aqueous electrolyte for a water-based battery based on mesoporous nanoparticles:

[0056] The raw materials for preparing the electrolyte are calculated by weight percentage, including 0.3% spherical mesoporous silica, 33% zinc sulfate heptahydrate, and the balance is water supplemented to 100%.

[0057] The preparation method of the spherical mesoporous silica is as Figure 2 shown, including the following steps:

[0058] (1) Add 0.1 g of F127 surfactant and 1 mL of ammonia water to water, heat to 60 °C, and stir to form a uniform micelle precursor solution;

[0059] (2) Add 1 mL of tetraethyl orthosilicate as a silica precursor to the above solution, stir at a speed of 1000 revolutions per minute, after stirring for two hours, when the solution turns light blue, continue to react for 24 hours to obtain a milky white solution;

[0060] (3) Centrifuge the above solution and use tetrahydrofuran to extract the surfactant to obtain a highly dispersed white powder, which is spherical mesoporous silica (diameter 20-60 nm).

[0061] The composite electrolyte is prepared by adding the spherical mesoporous silica powder obtained in the above steps to the zinc sulfate electrolyte at a mass fraction of 0.3%, and dispersing it evenly by ultrasonic or stirring.

[0062] The assembly of a long-life and highly stable Zn / / Zn symmetric water-based battery is to combine two zinc metal discs with a diameter of 12 mm and a glass fiber diaphragm with a diameter of 16 mm in a zinc|membrane|zinc sandwich structure, and add the obtained electrolyte to obtain a long-life and highly stable Zn / / Zn symmetric water-based battery.

[0063] The assembly of a long - life and highly stable zinc - manganese battery is to combine a zinc metal disc with a diameter of 12 mm, a glass fiber separator with a diameter of 16 mm, and a manganese dioxide positive electrode disc with a diameter of 12 mm in a zinc|membrane|manganese dioxide sandwich structure, and add the obtained electrolyte to get a long - life and highly stable zinc - manganese aqueous battery.

[0064] The assembly of a long - life and highly stable zinc - vanadium battery is to combine a zinc metal disc with a diameter of 12 mm, a glass fiber separator with a diameter of 16 mm, and a vanadium oxide positive electrode disc with a diameter of 12 mm in a zinc|membrane|vanadium oxide sandwich structure, and add the obtained electrolyte to get a long - life and highly stable zinc - vanadium aqueous battery.

[0065] As Figure 3 The transmission electron microscope images show that the mesoporous silica nanoparticles prepared by the present invention are composed of ultra - small mesoporous - level hollow nanospheres, with a pore diameter of 43 nm and an ultra - thin wall thickness of 4 - 5 nm. Figure 4 The nitrogen adsorption - desorption isotherms show a typical type - IV curve. The obtained surface area is 536 m 2 / g, the pore volume is 1.15 cm 3 / g, and the average pore diameter is 33.2 nm. As Figure 5 shown, adding mesoporous nanoparticles can significantly improve the ionic conductivity of the aqueous electrolyte. When the addition amount is 0.3%, the ionic conductivity of the electrolyte can increase to 82 mS / cm; adding an excessive amount of mesoporous nanoparticles will significantly increase the viscosity of the electrolyte, resulting in hindered ion transport. Preferably, the addition amount of the mesoporous silica nanoparticles in this example is controlled to be 0.1 - 2%. As Figure 6 shown, adding mesoporous silica nanoparticles can accelerate the ion desolvation of the electrolyte. From the results of the desolvation energy fitted by the variable - temperature electrochemical impedance spectroscopy, the desolvation energy of the aqueous battery composite electrolyte based on mesoporous nanoparticles is reduced to 36.61 kJ / mol. As Figure 7 shown, the scanning electron microscope image of the zinc electrode after the operation of the Zn / / Zn symmetric aqueous battery using the composite electrolyte shows the formation of a stable mesoporous silica interface layer, and the uniform and dendrite - free deposition of zinc metal. Based on the high ionic conductivity, fast desolvation and stable interface achieved by the aqueous battery composite electrolyte of the above - mentioned mesoporous nanoparticles, the Zn / / Zn symmetric aqueous battery achieves very excellent cycle life. At a high discharge depth of 29%, it can achieve stable operation for more than 1600 h at 4 mA / cm 2 、2 mAh / cm 2

[0066] ​The assembled zinc-vanadium aqueous battery in Example 1 has a discharge capacity as high as 401 mAh / g at a current density of 0.02 A / g, and can still maintain a discharge capacity of 197 mAh / g when the current density is increased to 2 A / g; after 2000 cycles at 1 A / g, it still maintains a discharge capacity of 175 mAh / g, showing excellent advantages of high capacity, high rate, and long cycle life.

[0067] The discharge capacities of the assembled zinc-manganese aqueous battery in Example 1 are 300, 305, 290, 245, 198, 163, and 139 mAh / g at current densities of 0.02, 0.04, 0.06, 0.1, 0.5, 1.0, and 2.0 A / g respectively, and can stably cycle more than 1000 times.

[0068] Example 2

[0069] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0070] The specific implementation method is the same as that of Example 1. The difference from Example 1 is that the mass percentage of the added mesoporous silica powder is 1%.

[0071] Example 3

[0072] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0073] The specific implementation method is the same as that of Example 1. The difference from Example 1 is that the inorganic salt is replaced with a mixture of zinc sulfate and lithium sulfate. The preparation method of the composite electrolyte is to add spherical mesoporous silica powder into the electrolyte of 1 mol / L zinc sulfate + 1 mol / L lithium sulfate with a mass fraction of 0.3%.

[0074] An assembly of a long-life and highly stable zinc-lithium manganese oxide battery is to combine a zinc metal disc with a diameter of 12 mm, a glass fiber separator with a diameter of 16 mm, and a lithium manganese oxide positive electrode disc with a diameter of 12 mm in a zinc|membrane|lithium manganese oxide sandwich structure, and add the obtained electrolyte to obtain a long-life and highly stable zinc-lithium manganese oxide aqueous battery. The prepared zinc-lithium manganese oxide aqueous battery has a cycle life of more than 1000 cycles.

[0075] Example 4

[0076] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0077] The specific implementation method is the same as that of Example 1. The difference from Example 1 is that the inorganic salt is replaced with magnesium sulfate. The preparation method of the composite electrolyte is to add spherical mesoporous silica powder into the electrolyte of 2 mol / L magnesium sulfate with a mass fraction of 0.3%.

[0078] The assembly of a long - life and highly stable magnesium - ion aqueous battery is to combine a circular activated carbon sheet with a diameter of 12 mm, a glass fiber separator with a diameter of 16 mm, and a manganese dioxide positive electrode circular sheet with a diameter of 12 mm in an activated carbon|membrane|manganese dioxide sandwich structure, and add the obtained electrolyte to obtain a long - life, highly stable, fast - charging and discharging magnesium - ion aqueous battery. The prepared magnesium - ion aqueous battery can meet 10C fast charging and discharging, with a capacity retention rate exceeding 70% and a cycle life exceeding 3000 cycles.

[0079] Example 5

[0080] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0081] Its specific implementation method is the same as that of Example 1. The difference from Example 1 is that the inorganic salt is replaced with zinc trifluoromethanesulfonate. The preparation method of the composite electrolyte is to add spherical mesoporous silica powder into the electrolyte of 30% zinc trifluoromethanesulfonate with a mass fraction of 0.3%.

[0082] The prepared zinc - ion aqueous battery can meet 20C fast charging and discharging, with a capacity retention rate exceeding 80% and a cycle life exceeding 5000 cycles.

[0083] Example 6

[0084] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0085] Its specific implementation method is the same as that of Example 1. The difference from Example 1 is that isopropanol organic solvent is added as an additive. The preparation raw materials of the electrolyte are calculated by weight percentage, including 0.3% spherical mesoporous silica, 33% zinc sulfate heptahydrate, 10% isopropanol, and water is added to make up the balance to 100%.

[0086] The prepared Zn / / Zn symmetric aqueous battery achieves excellent cycle life, stably operates for more than 2000 h, and the cycle life of the zinc - ion aqueous battery exceeds 3000 cycles.

[0087] Example 7

[0088] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0089] Its specific implementation method is the same as that of Example 1. The difference from Example 1 is that polyvinylpyrrolidone surfactant is added as an additive. The preparation raw materials of the electrolyte are calculated by weight percentage, including 0.3% spherical mesoporous silica, 33% zinc sulfate heptahydrate, 2% polyvinylpyrrolidone, and water is added to make up the balance to 100%.

[0090] The prepared Zn / / Zn symmetric aqueous battery achieves excellent cycle life, stably operates for more than 2500 h, and the cycle life of the zinc-ion aqueous battery exceeds 2000 cycles.

[0091] Example 8

[0092] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0093] The specific implementation method is the same as that of Example 1. The difference from Example 1 is that polyvinylpyrrolidone surfactant is added as an additive. The preparation raw materials of the electrolyte are calculated by weight percentage, including 0.3% spherical mesoporous silica, 33% zinc sulfate heptahydrate, 2% polyvinylpyrrolidone, and water is added to make up the balance to 100%.

[0094] The prepared Zn / / Zn symmetric aqueous battery achieves excellent cycle life, stably operates for more than 1500 h, and the cycle life of the zinc-ion aqueous battery exceeds 2000 cycles.

[0095] Example 9

[0096] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0097] The preparation raw materials of the electrolyte are calculated by weight percentage, including 0.5% spherical mesoporous titanium dioxide, 30% KOH, and water is added to make up the balance to 60%.

[0098] The preparation method of the spherical mesoporous titanium dioxide includes the following steps:

[0099] (1) Dissolve 0.1 g of P108 surfactant in tetrahydrofuran, add 5 mL of acetic acid solution, heat to 40 °C, and stir to form a uniform micelle precursor solution;

[0100] (2) Add 1 mL of tetrabutyl titanate as a titanium dioxide precursor to the above solution, stir for 5 minutes, and then let it stand and react in a non-blowing oven for 24 hours to obtain a light yellow gel;

[0101] (3) Uniformly mix the above gel with 40 mL of ethanol, place it in a polytetrafluoroethylene reaction kettle, and carry out hydrothermal reaction at 120 °C for 5 hours to obtain a white powder; the powder is annealed at 550 °C at high temperature to remove the surfactant to obtain spherical mesoporous titanium dioxide with a diameter of 30 - 80 nm.

[0102] The composite electrolyte is prepared by adding the spherical mesoporous titanium dioxide obtained in the above steps to the potassium hydroxide electrolyte with a mass fraction of 0.5%, and dispersing it evenly by ultrasonic wave or stirring.

[0103] The assembly of a long - life and highly stable zinc - nickel aqueous battery is to combine a zinc oxide negative electrode disc with a diameter of 12 mm, a glass fiber separator with a diameter of 16 mm, and a nickel hydroxide positive electrode disc with a diameter of 12 mm in a zinc oxide|membrane|nickel hydroxide sandwich structure, and add the electrolyte obtained above to obtain a long - life and highly stable zinc - nickel aqueous battery. The prepared zinc - nickel aqueous battery can meet 10C rapid charge and discharge, with a capacity retention rate exceeding 90%, and a cycle life exceeding 3000 cycles.

[0104] Example 10

[0105] An aqueous battery composite electrolyte based on mesoporous nanoparticles:

[0106] Its specific implementation method is the same as that of Example 1. The difference from Example 1 is that the spherical mesoporous nanoparticles are replaced by mesoporous polydopamine. The preparation method of mesoporous polydopamine includes the following steps:

[0107] (1) Dissolve 0.1 g of F127 surfactant in deionized water, add 0.5 mL of concentrated ammonia water, and stir at a rate of 350 revolutions per minute at room temperature for 2 hours;

[0108] (2) Add 0.5 g of dopamine hydrochloride to the above solution and continue stirring for three hours to obtain a black solution;

[0109] (3) After centrifuging and washing the above solution, anneal it under nitrogen atmosphere protection at 350 °C for 3 hours to obtain 20 - 80 nm spherical mesoporous dopamine;

[0110] The prepared zinc - nickel aqueous battery can meet 10C rapid charge and discharge, with a capacity retention rate exceeding 85%, and a cycle life exceeding 2500 cycles.

[0111] Comparative Example 1

[0112] Its specific implementation scheme is the same as that of Example 1. The difference from Example 1 is that mesoporous silica is not added.

[0113] Comparative Example 2

[0114] Its specific implementation scheme is the same as that of Example 1. The difference from Example 1 is that mesoporous silica is replaced by 50 nm gas - phase silica spheres without mesoporous characteristics in diameter.

[0115] As Figure 6 shown, the ion desolvation ability of the aqueous electrolyte without mesoporous nanoparticles in Comparative Example 1 is weak, and its desolvation energy is 49.43 kJ / mol. As Figure 8As shown, the Zn / / Zn symmetric cells assembled with the electrolytes of Comparative Example 1 (without adding mesoporous nanoparticles) and Comparative Example 2 (adding fumed silica spheres without mesoporous structure) have relatively short cycle lives, and both short-circuit and fail within 500 hours. This is due to the formation of negative dendrites and interfacial side reactions. The zinc-vanadium aqueous batteries assembled with the electrolytes of Comparative Example 1 and Comparative Example 2 have a discharge capacity of 359 mAh / g at a current density of 0.02 A / g, and fail due to dendrites and side reactions after only several hundred cycles. The initial discharge capacities of the zinc-manganese aqueous batteries assembled with the electrolytes of Comparative Example 1 and Comparative Example 2 are only 275 and 253 mAh / g at 0.02 A / g, and sharply decay to 18 and 10 mAh / g at 2 A / g. It can be seen that the aqueous batteries assembled without adding mesoporous nanoparticles have low specific capacity, poor fast charge-discharge ability, and poor cycle performance.

[0116] The present invention proposes a novel aqueous battery composite electrolyte based on mesoporous nanoparticles to solve the problems of slow desolvation, side reactions, and interfacial instability of aqueous batteries in aqueous electrolytes, and to achieve high-capacity and long-cycle aqueous batteries. Compared with the existing electrolytes, the mesoporous nanoparticles in the present invention have the advantages of less usage amount, large specific surface area, small particle size, and low cost; the obtained electrolyte has higher conductivity, faster desolvation rate, fewer corrosion side reactions, more stable electrode / electrolyte interface, and faster kinetic behavior; and this electrolyte can endow the aqueous battery with higher energy density, higher fast charge-discharge ability, and longer service life.

[0117] The above description of the embodiments is intended to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A composite electrolyte for aqueous batteries based on mesoporous nanoparticles, characterized in that: including mesoporous nanoparticles, inorganic salts and water; The particle size of the mesoporous nanoparticles is between 10 and 100 nm, and the pore size is between 2 and 50 nm.

2. The aqueous battery composite electrolyte based on mesoporous nanoparticles according to claim 1, characterized in that: including mesoporous nanoparticles, inorganic salts, water and organic additives; The raw material ratios of the electrolyte are calculated by weight percentage, wherein the mesoporous nanoparticles are 0.1-5%, the inorganic salts are 20-65%, the organic additives are 0-30%, and the rest is water supplemented to 100%.

3. The aqueous battery composite electrolyte based on mesoporous nanoparticles according to claim 2, characterized in that: The organic additive includes one or a mixture of multiple organic solvents and surfactants soluble in water.

4. The aqueous battery composite electrolyte based on mesoporous nanoparticles according to claim 3, characterized in that: The water-soluble organic solvent is one of methanol, ethanol, isopropanol, acetone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, formaldehyde, glucose or a mixture of multiple thereof; The surfactant is one of polyvinyl pyrrolidone, polyvinyl alcohol, sodium lauryl sulfate, hexadecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium chloride, or a mixture of multiple thereof.

5. The aqueous battery composite electrolyte based on mesoporous nanoparticles according to claim 1, characterized in that: The mesoporous nanoparticles include one or more of mesoporous silica, mesoporous titanium dioxide, mesoporous zinc oxide, mesoporous aluminum oxide, mesoporous dopamine, and a mesoporous metal organic framework.

6. The aqueous battery composite electrolyte based on mesoporous nanoparticles according to claim 1, characterized in that: The inorganic salt includes one or a mixture of multiple types of water-soluble zinc salt, sodium salt, lithium salt, potassium salt and magnesium salt.

7. The aqueous battery composite electrolyte based on mesoporous nanoparticles according to claim 6, characterized in that: The zinc salt is one or a mixture of multiple of zinc sulfate, zinc chloride, zinc acetate, zinc trifluoromethanesulfonate and zinc perchlorate; The sodium salt is one or a mixture of multiple of sodium chloride, sodium bromide, sodium sulfate, sodium trifluoromethanesulfonate, and sodium perchlorate; The lithium salt is one or a mixture of multiple of lithium chloride, lithium bromide, lithium sulfate, lithium trifluoromethanesulfonate, and lithium trifluoromethanesulfonyl imide; The potassium salt is one or a mixture of potassium chloride, potassium bromide, potassium sulfate, potassium fluoride, potassium carbonate; The magnesium salt is one of magnesium chloride, magnesium sulfate, magnesium trifluoromethanesulfonate and magnesium perchlorate or a mixture of multiple thereof.

8. The aqueous battery composite electrolyte based on mesoporous nanoparticles according to claim 1, characterized in that: The method for preparing the mesoporous nanoparticles comprises the following steps: S1: The surfactant is uniformly dispersed in the aqueous phase to form a clear and transparent micellar solution; S2: dissolving the nanoparticle precursor in the above micelle solution, stirring and reacting for a period of time to generate a product; S3: The product is filtered, washed and calcined to obtain mesoporous nanoparticles with good dispersion.

9. The aqueous battery composite electrolyte based on mesoporous nanoparticles according to claim 8, characterized in that: The surfactant in step S1 is one or more of P123, P103, F127, F108, trimethylhexadecyl ammonium bromide, PS-PEO-PVP, PS-PEO, and PS-PVP; In step S2, the nanoparticle precursor is one or more of tetraethyl silicate, tetrabutyl titanate, dopamine, zinc nitrate, zinc chloride, ferric nitrate, ferric chloride, and Prussian blue; and the reaction time is 2-24 hours.

10. An application of the composite electrolyte for aqueous batteries based on mesoporous nanoparticles according to any one of claims 1 to 9, characterized in that: The aqueous battery composite electrolyte based on mesoporous nanoparticles is used in aqueous batteries, and the aqueous batteries include one or more of zinc-based aqueous batteries, sodium ion aqueous batteries, lithium ion aqueous batteries, potassium ion aqueous batteries, and magnesium ion aqueous batteries.

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