A zinc anode with a stress-responsive interface modification layer, a preparation method thereof, and a zinc-ion battery

Abstract

The present invention relates to a zinc negative electrode with a stress-responsive interface modification layer, a preparation method thereof, and a zinc-ion battery, belonging to the technical field of zinc negative electrode interface modification for aqueous zinc-ion batteries. The thickness of the interface modification layer is 0.1 μm to 20 μm, and it is uniformly distributed on the surface of the zinc negative electrode; the material of the interface modification layer is polyborosiloxane with shear thickening characteristics. The interface modification layer has good conductivity and stress response characteristics, can effectively inhibit the growth of zinc dendrites, optimizes the zinc ion deposition behavior at the interface of the metal zinc negative electrode, and helps to improve the cycle stability of the aqueous zinc-ion battery; the present invention also provides a preparation method of a zinc negative electrode with a stress-responsive interface modification layer, which uniformly forms a stress-responsive interface modification layer on the surface of the metal zinc negative electrode by a solvent evaporation method to protect the metal zinc negative electrode and effectively inhibit the growth of zinc dendrites; the aqueous zinc-ion battery is a button battery or a soft-pack battery.

Description

Technical Field

[0001] The present invention relates to a zinc negative electrode with a stress-responsive interface modification layer, a preparation method thereof, and a zinc-ion battery, belonging to the technical field of zinc negative electrodes for aqueous zinc-ion batteries. Background Art

[0002] With the continuous development of the new energy industry, people's requirements for the safety and energy density of secondary batteries are getting higher and higher. In the current energy storage system, the performance of lithium-ion batteries is significantly better than other systems. The widespread use of lithium-ion batteries has greatly changed today's communication and transportation methods and promoted the transformation in the energy and transportation fields. With the booming development of portable electronic devices and electric vehicles, people's demand for high specific energy batteries is also increasing continuously. However, there are many limitations to the further improvement of the performance of lithium-ion batteries. In particular, the limited theoretical specific capacity (372 mAh / g) of the graphite negative electrode greatly restricts the capacity improvement of lithium-ion batteries. Traditional lithium-ion batteries are difficult to meet the current demand for high specific energy batteries. Therefore, the research and development of new secondary batteries is particularly important. Compared with lithium-ion batteries, zinc-ion batteries (AZIBs) have the characteristics of high safety, low cost, high theoretical specific capacity (820 mAh / g), and environmental friendliness. Moreover, metallic zinc has rich reserves and good chemical stability.

[0003] Currently, the research and development of aqueous zinc-ion batteries face three main problems: uncontrollable zinc dendrites, zinc negative electrode corrosion, and hydrogen evolution reaction. On the one hand, the uncontrollable growth of zinc dendrites consumes a considerable amount of metallic zinc and may penetrate the separator, resulting in battery short circuit, reducing the reversibility and cycle life of the battery. On the other hand, side reactions such as zinc negative electrode corrosion and hydrogen evolution irreversibly consume the electrolyte and produce insoluble by-products and hydrogen gas, leading to an increase in electrode polarization. In addition, the generated gas may cause an increase in the internal pressure of the battery, thus posing a safety hazard. Therefore, the research and development of aqueous zinc-ion batteries urgently need to solve the problems of uncontrollable growth of zinc dendrites and side reactions faced by the zinc negative electrode.

[0004] Constructing an artificial solid-electrolyte interface membrane (artificial SEI) on the zinc negative electrode to achieve the modification of the metal zinc negative electrode interface has been proven to be an effective means to improve the cycle performance of aqueous zinc-ion batteries. Constructing an artificial SEI on the surface of the zinc negative electrode can isolate the direct contact between zinc metal and the electrolyte, thereby inhibiting the occurrence of side reactions on the zinc negative electrode. Moreover, the inherent mechanical strength of the artificial SEI layer is used to achieve the purpose of inhibiting the growth of zinc dendrites, effectively improving the long-term cycle stability of aqueous zinc-ion batteries.

[0005] However, the artificial SEI layer in the prior art can well inhibit the growth of zinc dendrites at the initial stage, but it will still be inevitably damaged as the cycling progresses; and for the zinc anode interface modification layers reported currently, most of them adopt interface modification layers with constant mechanical strength to achieve mechanical inhibition of the growth of zinc dendrites. However, the interface modification layer cannot change its own strength accordingly according to the dynamic situation of the growth of zinc dendrites, resulting in a large inherent interface impedance. In addition, most of the interface modification materials themselves do not have zinc ion conductivity, which greatly increases the interface impedance of the zinc anode and leads to a decrease in the zinc ion transport efficiency. For example, a highly polar β-phase polyvinylidene fluoride (β-PVDF) protective layer is coated on the surface of the zinc anode through a spin-coating process. The elastic and firm β-PVDF layer regulates the deposition and dissolution processes of zinc ions, inhibits the occurrence of hydrogen evolution corrosion and side reactions, but this material is not conductive to zinc ions, which hinders ion migration to a certain extent and has an insignificant effect on regulating the uniform deposition of zinc ions. Therefore, the research on zinc metal anode interface modification materials and interface layer preparation processes is of great significance for realizing practical aqueous zinc ion batteries.

[0006] In addition, there is work indicating that the polyborosiloxane can also be used as an anode interface modification layer in lithium ion batteries and lithium metal batteries, but it does not show obvious improvement effects in terms of improving the cycle life and Coulomb efficiency of lithium batteries, which is mainly attributed to the relatively weak ion conductivity of the polyborosiloxane. Summary of the Invention

[0007] In order to overcome the defects existing in the prior art, one of the objectives of the present invention is to provide a zinc anode with a stress-responsive interface modification layer. The interface modification layer has good conductivity and stress-responsive characteristics, can effectively inhibit the growth of zinc dendrites, optimizes the zinc ion deposition behavior at the interface of the metal zinc anode, and helps to improve the cycle stability of the aqueous zinc ion battery.

[0008] Another objective of the present invention is to provide a preparation method for a zinc anode with a stress-responsive interface modification layer; a stress-responsive interface modification layer is uniformly formed on the surface of the metal zinc anode through a solvent evaporation method to protect the metal zinc anode and effectively inhibit the growth of zinc dendrites.

[0009] Another objective of the present invention is to provide a zinc ion battery, and the negative electrode of the zinc ion battery is the zinc anode with a stress-responsive interface modification layer of the present invention.

[0010] The objectives of the present invention are achieved through the following technical solutions.

[0011] A zinc anode with a stress-responsive interface modification layer, the thickness of the interface modification layer is 0.1 μm to 20 μm, and the interface modification layer is uniformly distributed on the surface of the zinc anode;

[0012] The structural general formula of the polyborosiloxane is R1-[Si(R2R3)-O] n -B-R4R5, where n represents the degree of polymerization of the -Si(R2R3)-O- units in the polyborosiloxane molecular chain, and the value is a positive integer from 10 to 150;

[0013] R1 is the end group connected to Si, and R1 is methyl, hydroxyl, vinyl or a siloxane chain;

[0014] R2 and R3 represent the side chains connected to silicon in the repeating unit, and R2 and R3 are respectively independent hydrogen, methyl, aminopropyl or phenyl;

[0015] R4 and R5 represent the side chains connected to the boron atom, and R4 and R5 are respectively independent of at least one of hydroxyl, β-cyclodextrin molecular chain and polyoxosilane chain;

[0016] The structural general formula of the polyoxosilane chain is R1’-[Si(R2’R3’)-O] n -, where R2’, R3’ and n are respectively consistent with R2, R3 and n in the structural general formula R1-[Si(R2R3)-O] n -B-R4R5, and R1’ is methyl, vinyl, hydroxyl or -[Si(R A R B )-O] n -H, and -[Si(R A R B )-O] n -H in which R A 、R B and n are respectively consistent with R2’, R3’ and n in the structural general formula of the polyoxosilane chain R1’-[Si(R2’R3’)-O] n -.

[0017] Preferably, in the structural general formula of the polyborosiloxane, the value of n is a positive integer from 28 to 140.

[0018] More preferably, in the structural general formula of the polyborosiloxane, the value of n is a positive integer from 30 to 80.

[0019] Preferably, the thickness of the interface modification layer is 1 μm to 12 μm; if the thickness of the interface modification layer is too thin, it is difficult to ensure the strength of the interface modification layer, and if the thickness is too thick, the interface resistance of the battery will increase suddenly.

[0020] Preferably, a zinc salt or an organic macromolecular material with zinc ion transport characteristics is further added to the interface modification layer to increase the ion transport capacity of the interface modification layer; in the interface modification layer, the mass fraction of the zinc salt or the organic macromolecular material is 1% to 50%.

[0021] The zinc salt is at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc bis(trifluoromethanesulfonate), and zinc bis(trifluoromethanesulfonimide).

[0022] The organic macromolecular material with zinc ion transport characteristics is at least one of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and phenazine.

[0023] A method for preparing a zinc negative electrode with a stress-responsive interface modification layer according to the present invention, the method being a solvent evaporation method;

[0024] Specifically, the method steps are as follows:

[0025] (1) In an air atmosphere, the polyborosiloxane is completely dissolved in a diluent to form a homogeneous and transparent dispersion;

[0026] In the dispersion, the mass fraction of the polyborosiloxane is 1% to 10%;

[0027] The diluent is at least one of petroleum ether, n-hexane, cyclohexane, carbon disulfide, carbon tetrachloride, benzene, toluene, dichloroethane, dichloromethane, chloroform, diphenyl ether, ether, and tetrahydrofuran;

[0028] (2) The dispersion obtained in step (1) is uniformly dispersed on the surface of the metallic zinc negative electrode, and dried at normal pressure or reduced pressure until the diluent is completely volatilized; as the diluent volatilizes, the polyborosiloxane gradually contacts the surface of the zinc negative electrode, and during the subsequent complete volatilization process, it closely adheres to the metallic zinc negative electrode, and finally an interface modification layer is formed on the surface of the zinc negative electrode.

[0029] An aqueous zinc ion battery, the aqueous zinc ion battery being a button battery or a soft-pack battery, the zinc ion battery being composed of a positive electrode, a negative electrode, a separator, and an electrolyte;

[0030] Among them, the negative electrode is the zinc negative electrode with a stress-responsive interface modification layer according to the present invention;

[0031] The positive electrode is a positive electrode material commonly used in the field of aqueous zinc ion batteries in the prior art;

[0032] The separator is a separator material commonly used in the field of aqueous zinc ion batteries in the prior art;[[ID=3,7]]

[0033] The electrolyte is an electrolyte commonly used in the field of aqueous zinc ion batteries in the prior art.

[0034] Preferably, the cathode material is at least one of vanadium-based materials, manganese-based materials, iron-based materials, and sulfide materials; the vanadium-based materials include vanadium oxides or hydrated vanadium oxides; the manganese-based materials include manganese oxides; the iron-based materials include iron oxides; the sulfide materials include molybdenum disulfide or manganese sulfide;

[0035] The separator material is glass fiber or cellulose;

[0036] The electrolyte is an aqueous zinc salt solution or a mixed solution of zinc salt and neutral salt; wherein, the zinc salt is at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc bis(trifluoromethanesulfonate), and zinc bis(trifluoromethanesulfonyl)imide; the neutral salt includes lithium salt, sodium salt, or potassium salt.

[0037] Beneficial effects

[0038] (1) The present invention provides a zinc negative electrode with a stress-responsive interface modification layer. The material of the stress-responsive interface modification layer is polyborosiloxane with shear thickening characteristics, and it closely adheres to the surface of the zinc metal negative electrode by relying on the deformation characteristics of polyborosiloxane; different from the traditional interface modification layer, the stress-responsive interface modification layer described in the present invention can, when local zinc dendrites grow on the negative electrode, achieve an increase in the strength of the corresponding position through the association of non-covalent dynamic bonds (such as B-O dynamic bonds) within and between molecular chains inside, inhibit the further growth of zinc dendrites, and promote the deposition of zinc ions into the area around the dendrites, realizing the uniform deposition of zinc ions on the surface of the zinc negative electrode; when the growth of dendrites is inhibited, the dynamic bonds inside the interface modification layer spontaneously dissociate, resulting in a decrease in its own strength, and the modification layer also changes from a local gel solid state to a uniform gel liquid state, realizing the stable transmission of zinc ions at the interface, and solving the problem of large interface impedance caused by the invariable strength of the traditional interface modification layer.

[0039] (2) The present invention provides a zinc negative electrode with a stress-responsive interface modification layer. The thickness of the stress-responsive interface modification layer is 0.1 μm to 20 μm, and preferably the thickness of the interface modification layer is 1 μm to 12 μm; the thickness of the interface modification layer will affect the interfacial ion transport of the battery to a considerable extent. The ion conductivity of the interface modification material used in the present invention is relatively low. If the interface layer is made too thick, it will greatly increase the negative electrode interface impedance of the battery and affect the cycle performance of the battery. Therefore, the interface modification layer must be controlled within a suitable thickness to minimize the impact on the interfacial zinc ion transport while protecting the zinc negative electrode using the shear thickening mechanism based on stress response.

[0040] (3) The present invention provides a zinc negative electrode with a stress-responsive interface modification layer. The material of the interface modification layer has a structural general formula of R1-[Si(R2R3)-O] n-B-R4R5 polyborosiloxane; the interface modification layer can adjust its own mechanical strength and flexibility according to different zinc-ion aqueous battery systems and working condition requirements: when the zinc-ion deposition is slow, the interface modification layer can achieve uniform deposition of zinc ions relying on its initial strength without relying on shear thickening to improve the mechanical strength of the interface modification layer, avoiding unnecessary zinc-ion conductivity loss; and the lower the strength of the interface modification layer, the faster it closely adheres to the zinc negative electrode surface. On the premise of having a certain deformation ability and adjustable mechanical strength, the interface modification layer of the present invention can design different initial strengths according to needs to control the adhesion time between the modification layer and the negative electrode surface.

[0041] (4) The present invention provides a zinc negative electrode with a stress-responsive interface modification layer. In terms of the composition of the interface modification layer, a single or multiple polyborosiloxanes with shear thickening effects can be used. The reversible association / dissociation process of non-covalent dynamic bonds within and between molecular chains is utilized to achieve changes in its own strength, and the vibration of molecular chains is relied on to achieve the transmission of zinc ions at the interface; at the same time, the zinc salt can also be added to the interface modification layer or a chemical bonding method can be adopted to connect a macromolecular substance with a zinc-ion transport channel to the end of the organosiloxane chain, promoting the transport of zinc ions in the interface layer while suppressing the growth of zinc dendrites through stress response.

[0042] (5) The present invention provides a preparation method of a zinc negative electrode with a stress-responsive interface modification layer. The method steps are simple and easy to operate. A uniform interface modification layer is constructed on the metal zinc negative electrode through the solvent evaporation method; the polyborosiloxane, which is the material of the zinc negative electrode interface modification layer, has the characteristics of stress response and the ability of slow deformation, and can slowly deform to fill the tiny pores between the interface modification layer material and the zinc negative electrode interface caused by the volatilization of the diluent during the formation of the modification layer, thereby achieving complete adhesion between the interface modification layer and the zinc metal negative electrode at the microscale, timely responding to the stress concentration caused by the uneven deposition of zinc metal at the microscale locally, and minimizing the additional impedance caused by the introduction of the modification layer; by regulating the mass fraction of the polyborosiloxane after being dispersed in the diluent, the thickness of the interface modification layer is regulated, protecting the zinc negative electrode while minimizing the impact of the polyborosiloxane layer on the battery operation.

[0043] (6) The present invention provides an aqueous zinc-ion battery, and the negative electrode of the battery is the zinc negative electrode with a stress-responsive interface modification layer of the present invention; in an aqueous zinc-ion battery, in addition to the zinc dendrite problem caused by the uneven deposition of zinc ions on the surface of the negative electrode during cycling, there are also hydrogen evolution and corrosion problems caused by the direct exposure of the zinc negative electrode to the aqueous electrolyte environment, and the latter is the most prominent aspect affecting the performance of the aqueous zinc-ion battery; the polyborosiloxane of the present invention has excellent film-forming properties and weak polarity. When a modification layer is formed on the surface of the zinc negative electrode, its relatively hydrophobic characteristics result in negligible swelling behavior of the polyborosiloxane in the aqueous electrolyte. The polyborosiloxane uniformly covers the surface of the negative zinc metal, avoiding hydrogen evolution and corrosion phenomena caused by the direct contact between the zinc negative electrode and the aqueous electrolyte, improving the interfacial stability of the zinc negative electrode during operation, and enhancing the cycle life of the aqueous zinc-ion battery with the polyborosiloxane interface modification layer; the interface modification layer has a stress-responsive characteristic based on the shear thickening effect, and can dynamically adjust the strength of the corresponding position according to the growth of local zinc dendrites while remaining in a low-strength gel state at other positions, minimizing the loss of zinc ion conductivity caused by the increase in the local strength of the interface layer while effectively inhibiting the growth of zinc dendrites, and can increase the cycle life of the aqueous zinc-ion battery by more than 3 times; in addition, by adding the zinc salt to the polyborosiloxane interface modification layer or using a chemical bonding method to connect a macromolecular substance with a zinc ion transport channel to the end of the organosiloxane chain, the ion transport ability of the interface layer is improved, making the polarization voltage of the aqueous zinc-ion battery with the polyborosiloxane interface modification layer similar to that of the aqueous zinc-ion battery without this modification layer (about 65 mV), overcoming the impedance increase caused by adding the interface layer. Detailed Embodiments

[0044] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. The methods are conventional methods unless otherwise specified, and the raw materials can be obtained from public commercial channels unless otherwise specified.

[0045] Assembly steps of button battery: Use a CR2032 stainless steel button battery case. Place the zinc negative electrode with a stress interface modification layer (diameter 11 mm, thickness 100 μm) of the present invention at the center of the negative electrode case. Place a separator (diameter 16 mm, thickness 675 μm) on the upper surface of the interface modification layer. Then, drop 130 μL of electrolyte with a molar concentration of 1 M above the separator, and place an aluminum foil (aluminum foil diameter 11 mm) coated with the positive electrode material slurry at the center of the separator. In the positive electrode material slurry, the mass ratio of each component is positive electrode material: Super P: PVDF = 8:1:1. Then, place a stainless steel gasket (diameter 15.8 mm, thickness 1 mm) and a stainless steel elastic sheet (diameter 15.4 mm, thickness 1.3 mm) successively facing the positive electrode sheet, fasten the positive electrode case, and use an MSK-110 battery sealing machine to hold for 3 s under a pressure of 50 kg / cm 2 to obtain the corresponding button battery.

[0046] Assembly steps of soft-pack battery: Place the zinc negative electrode with a stress interface modification layer (length 6 cm, width 4 cm, thickness 100 μm) and the positive electrode (aluminum foil coated with the positive electrode material slurry, aluminum foil size length 6 cm, width 4 cm, thickness 100 μm; in the positive electrode material slurry, the mass ratio of each component is positive electrode material: Super P: PVDF = 8:1:1) of the present invention facing each other, with a separator (length 7 cm, width 5 cm, thickness 675 μm) in the middle. Use green glue (width 11 mm, thickness 16 μm) to wind and fix the electrode sheets and the separator. Then, use an MSK-800W pole ear welding machine to weld nickel pole ears on the positive and negative electrodes respectively, and attach pole ear sealant on both sides of the pole ears; then use an aluminum-plastic film (length 20 cm, width 9 cm, thickness 113 μm) to neatly wrap the battery cell, and use an MSK-140 soft-pack battery sealing machine to perform top sealing and single-sided side sealing close to the edge of the battery cell. Inject 3.28 mL of electrolyte with a molar concentration of 1 M through the unsealed side and let it stand for 2 h to allow the electrolyte to fully infiltrate the electrodes; then use an MSK-115A-S vacuum pre-sealing machine to package to obtain a closed system, and cut off the excess aluminum-plastic film to obtain the target soft-pack battery.

[0047] Example 1

[0048] A zinc negative electrode with a stress-responsive interface modification layer, and the interface modification layer is uniformly distributed on the surface of the zinc negative electrode;

[0049] The material of the interface modification layer is polyborosiloxane with shear thickening characteristics; the structural formula of the polyborosiloxane is R1-[Si(R2R3)-O] n -B-R4R5;

[0050] wherein, n represents the degree of polymerization of the -Si(R2R3)-O- unit in the polyborosiloxane molecular chain, and the value is 60;

[0051] R1 is a terminal group connected to Si, and R1 is a methyl group;

[0052] R2 and R3 represent side chains connected to silicon in the repeating unit, and both R2 and R3 are methyl groups;

[0053] R4 and R5 represent side chains connected to the boron atom, R4 is a hydroxyl group and a polysiloxane chain CH3-[Si(CH3CH3)-O] 60 -, and R5 is a hydroxyl group and CH3-[Si(CH3CH3)-O] 60 -.

[0054] The polyborosiloxane described in this example is prepared according to the literature report, and the steps are as follows:

[0055] Weigh 5 g of the polysiloxane precursor CH3-[Si(CH3CH3)-O] 60 -H into a 100 mL beaker. While stirring, gradually add 50.1 mL of an aqueous boric acid solution with a molar concentration of 0.05 M to the beaker until the addition of the boric acid solution is complete. The mass ratio of the polysiloxane precursor to boric acid is 97:3; during the addition of the boric acid solution, maintain a rotation speed of 700 rpm and a temperature of 25 °C; after the addition of the boric acid solution is complete, keep the rotation speed unchanged and raise the temperature to 180 °C, and react for 6 h to obtain a viscoelastic solid, and transfer it to a 50 °C atmospheric pressure oven and keep it for 12 h to remove internal bubbles and residual moisture to obtain polyborosiloxane.

[0056] The polyborosiloxane obtained after the reaction is characterized by Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) (the wavenumber range is 4000 - 350 cm -1 ), and there is an obvious Si-O-B characteristic peak at 1337 cm -1 , that is, the polysiloxane precursor reacts with boric acid to form polyborosiloxane. There is a weak B-OH peak at 3224 cm -1 , that is, there are still unreacted hydroxyl groups in the boric acid connected to the chain ends, indicating that the polyborosiloxane (R1-[Si(R2R3)-O] n -B-R4R5) prepared by the method is a mixture and there are three structures:

[0057]

[0058] A method for preparing a zinc negative electrode with a stress-responsive interface modification layer described in this example, and the method is a solvent evaporation method;

[0059] Specifically, the steps of the method are as follows:

[0060] (1) Under an air atmosphere, add the polyborosiloxane into n-hexane, stir and dissolve it at 25 °C for 30 min at a rotation speed of 400 rpm to form a homogeneous and transparent dispersion; the mass fraction of the polyborosiloxane in the dispersion is 2%;

[0061] (2) Polish a zinc foil with a thickness of 100 μm until it is shiny using 3000-mesh sandpaper. During this process, use alcohol as a lubricant, then continue to polish it with 5000-mesh sandpaper for 3 min, cut it into circular pieces with a diameter of 11 mm, and evenly flatten the zinc pieces using the bottom of a glass bottle;

[0062] Uniformly drop 20 μL of the dispersion on the surface of the zinc piece, and then place it in an oven at 50 °C under normal pressure to dry for 6 h to volatilize n-hexane, obtaining the zinc negative electrode with a stress-responsive interface modification layer described in this example.

[0063] An aqueous zinc-ion battery, and the aqueous zinc-ion battery is a zinc-ion button battery, which is composed of a positive electrode, a negative electrode, a separator, and an electrolyte;

[0064] Among them, the negative electrode is the zinc negative electrode with a stress-responsive interface modification layer described in this embodiment;

[0065] The positive electrode material is lithium manganate;

[0066] The separator material is glass fiber;

[0067] The electrolyte is an aqueous solution of zinc sulfate with a molar concentration of 1 M.

[0068] Perform scanning electron microscope characterization on the zinc negative electrode with a stress-responsive interface modification layer prepared in Example 1. From the test results, it can be seen that the thickness of the stress-responsive interface modification layer is 3.1 μm.

[0069] Perform constant current charge-discharge tests on the aqueous zinc-ion button battery prepared in Example 1. The test instrument is a Neware CT-4008Tn battery test system, the test temperature is 30 °C, the areal specific capacity is 1 mAh / cm 2 , and the current densities are 1 mA / cm 2 , 5 mA / cm 2 and 10 mA / cm 2 , and the test results are shown in Table 1

[0070] Table 1 Test results of the cycle performance of the aqueous zinc-ion button battery at different current densities

[0071]

[0072] The test results show that the aqueous zinc-ion button battery with a zinc negative electrode having a stress-responsive interface modification layer described in this embodiment can exhibit good cycling performance and low interfacial impedance under both high-current and low-current conditions.

[0073] Example 2

[0074] Example 2 is only based on Example 1, replacing "the mass fraction of the polyborosiloxane in the dispersion liquid is 2%" in Example 1 with "the mass fraction of the polyborosiloxane in the dispersion liquid is 10%", and other conditions remain unchanged.

[0075] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 2 was characterized by scanning electron microscopy. From the test results, it can be known that the thickness of the stress-responsive interface modification layer is 12 μm.

[0076] The constant current charge-discharge test was carried out on the aqueous zinc-ion button battery prepared in Example 2. The test instrument was a Neware CT-4008Tn battery test system. At 30 °C, a current density of 5 mA / cm 2 and an areal specific capacity of 1 mAh / cm 2 conditions, the battery stably cycled for 100 h, and the voltage polarization during the cycling process was 85 mV, indicating that the aqueous zinc-ion button battery can still exhibit good cycling performance and low interfacial impedance under the condition of a relatively large thickness of the interface modification layer.

[0077] Example 3

[0078] Example 3 is only based on Example 1, adding zinc salt to the interface modification layer;

[0079] The zinc salt is zinc bis(trifluoromethanesulfonate), and in the interface modification layer, the mass fraction of the zinc salt is 1%.

[0080] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 3 was characterized by scanning electron microscopy. From the test results, it can be known that the thickness of the stress-responsive interface modification layer is 3.1 μm.

[0081] The constant current charge-discharge test was carried out on the aqueous zinc-ion button battery prepared in Example 3. The test instrument was a Neware CT-4008Tn battery test system. At 30 °C, a current density of 5 mA / cm 2 and an areal specific capacity of 1 mAh / cm 2 conditions, the battery stably cycled for 135 h, and the voltage polarization during the cycling process was 68 mV, indicating that the aqueous zinc-ion button battery exhibits good cycling performance and low interfacial impedance.

[0082] Example 4

[0083] Example 4 is based only on Example 1, with zinc salt added to the interface modification layer;

[0084] The zinc salt is zinc bis(trifluoromethanesulfonate), and in the interface modification layer, the mass fraction of the zinc salt is 20%.

[0085] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 4 was characterized by scanning electron microscopy. The test results show that the thickness of the stress-responsive interface modification layer is 3.1 μm.

[0086] The aqueous zinc-ion button battery prepared in Example 4 was subjected to a constant current charge-discharge test. The test instrument was a Neware CT-4008Tn battery test system. At 30 °C, a current density of 5 mA / cm 2 and an areal specific capacity of 1 mAh / cm 2 conditions, the battery stably cycled for 170 h, and the voltage polarization during the cycling process was 65 mV, indicating that the aqueous zinc-ion button battery exhibited good cycling performance and low interfacial impedance.

[0087] Example 5

[0088] Example 5 is based only on Example 1, with zinc salt added to the interface modification layer;

[0089] The zinc salt is zinc bis(trifluoromethanesulfonate), and in the interface modification layer, the mass fraction of the zinc salt is 50%.

[0090] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 5 was characterized by scanning electron microscopy. The test results show that the thickness of the stress-responsive interface modification layer is 3.2 μm.

[0091] The aqueous zinc-ion button battery prepared in Example 5 was subjected to a constant current charge-discharge test. The test instrument was a Neware CT-4008Tn battery test system. At 30 °C, a current density of 5 mA / cm 2 and an areal specific capacity of 1 mAh / cm 2 conditions, the battery stably cycled for 165 h, and the voltage polarization during the cycling process was 65 mV, indicating that after adding the zinc salt, the aqueous zinc-ion button battery exhibited good cycling performance and low interfacial impedance.

[0092] Example 6

[0093] Example 6 is based only on Example 1, with a macromolecule with a zinc ion channel added to the interface modification layer;

[0094] The macromolecule with a zinc ion channel is β-cyclodextrin, and in the interface modification layer, the mass fraction of β-cyclodextrin is 1%.

[0095] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 6 was characterized by scanning electron microscopy. From the test results, it can be known that the thickness of the stress-responsive interface modification layer is 3.1 μm.

[0096] The aqueous zinc-ion button battery prepared in Example 6 was subjected to a constant current charge-discharge test. The test instrument was the Neware CT-4008Tn battery test system. At a current density of 5 mA / cm 2 and an areal specific capacity of 1 mAh / cm 2 under the condition of, the battery was stably cycled for 130 h, and the voltage polarization during the cycling process was 69 mV, indicating that the aqueous zinc-ion button battery exhibited good cycling performance and low interfacial impedance.

[0097] Example 7

[0098] In Example 7, only on the basis of Example 1, a macromolecular substance with a zinc ion channel was added to the interface modification layer;

[0099] The macromolecular substance with a zinc ion channel is β-cyclodextrin, and in the interface modification layer, the mass fraction of β-cyclodextrin is 20%.

[0100] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 7 was characterized by scanning electron microscopy. From the test results, it can be known that the thickness of the stress-responsive interface modification layer is 3.2 μm.

[0101] The aqueous zinc-ion button battery prepared in Example 7 was subjected to a constant current charge-discharge test. The test instrument was the Neware CT-4008Tn battery test system. At a current density of 5 mA / cm 2 and an areal specific capacity of 1 mAh / cm 2 under the condition of, the battery was stably cycled for 400 h, and the voltage polarization during the cycling process was 65 mV, indicating that the aqueous zinc-ion button battery exhibited good cycling performance and low interfacial impedance.

[0102] Example 8

[0103] In Example 8, only on the basis of Example 1, a macromolecular substance with a zinc ion channel was added to the interface modification layer;

[0104] The macromolecular substance with a zinc ion channel is β-cyclodextrin, and in the interface modification layer, the mass fraction of β-cyclodextrin is 50%.

[0105] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 8 was characterized by scanning electron microscopy. From the test results, it can be known that the thickness of the stress-responsive interface modification layer is 3.3 μm.

[0106] The aqueous zinc ion button cell prepared in Example 8 was subjected to constant current charge and discharge tests using a Xinwei CT-4008Tn battery test system at 30°C and 5 mA / cm 2 Current density, 1 mAh / cm 2 Under the condition of area-to-capacity, the battery cycled stably for 280 h, and the voltage polarization during the cycle was 67 mV, indicating that after adding macromolecular substances with zinc ion channels, the aqueous zinc ion button battery showed good cycle performance and low interface impedance.

[0107] Example 9

[0108] Example 9 is based on Example 1, except that "the positive electrode material is lithium manganate" in Example 1 is replaced by "the positive electrode material is vanadium pentoxide", and other conditions remain unchanged.

[0109] The aqueous zinc ion button cell prepared in Example 9 was subjected to constant current charge and discharge tests using a Xinwei CT-4008Tn battery test system at 30°C and 5 mA / cm 2 Current density, 1 mAh / cm 2 Under the condition of area specific capacity, the battery still has a capacity retention rate of 80% after 100 cycles, indicating that the aqueous zinc ion button battery exhibits good cycle performance and low interface impedance.

[0110] Example 10

[0111] Example 10 is based on Example 1, except that "the electrolyte is an aqueous solution of zinc sulfate with a molar concentration of 1 M" in Example 1 is replaced by "the electrolyte is a mixed solution of zinc sulfate with a molar concentration of 1 M and lithium chloride with a molar concentration of 1 M", and other conditions remain unchanged.

[0112] The aqueous zinc ion button cell prepared in Example 10 was subjected to constant current charge and discharge tests using a Xinwei CT-4008Tn battery test system at 30°C and 5 mA / cm 2 Current density, 1 mAh / cm 2 Under the condition of area-to-capacity, the battery cycled stably for 100 h, and the voltage polarization during the cycle was 68 mV, indicating that the aqueous zinc ion button battery exhibited good cycle performance and low interface impedance.

[0113] Example 11

[0114] Example 11 is based on Example 1, except that "R2 and R3 are both methyl, and n is 60" in Example 1 is replaced by "R2 is methyl, R3 is hydrogen, and n is 140", and other conditions remain unchanged.

[0115] In this implementation, the polyborosiloxane is prepared according to the literature reports, and the steps are as follows:

[0116] Weigh 5 g of the polysiloxane precursor CH3-[Si(HCH3)-O] 140 -H into a 100 mL beaker. While stirring, gradually add 50.1 mL of an aqueous boric acid solution with a molar concentration of 0.05 M dropwise to the beaker until the addition of the boric acid solution is complete. The mass ratio of the polysiloxane precursor to boric acid is 97:3. During the addition of the boric acid solution, maintain a rotation speed of 700 rpm and a temperature of 25 °C. After the addition of the boric acid solution is complete, keep the rotation speed unchanged and raise the temperature to 180 °C, and react for 6 h to obtain a viscoelastic solid. Then transfer it to a 50 °C atmospheric oven and keep it for 12 h to remove internal bubbles and residual moisture, obtaining polyborosiloxane.

[0117] The polyborosiloxane obtained after the reaction is characterized by Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) (the wavenumber range is 4000 - 350 cm -1 ), and there is an obvious Si-O-B characteristic peak at 1337 cm -1 , indicating that the polysiloxane precursor reacts with boric acid to form polyborosiloxane. There is a weak B-OH peak at 3224 cm -1 , indicating that the boric acid connected to the chain end still has unreacted hydroxyl groups, indicating that the polyborosiloxane (R1-[Si(R2R3)-O] n -B-R4R5) prepared by the method is a mixture and has three structures:

[0118]

[0119] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 11 is characterized by scanning electron microscopy. From the test results, the thickness of the stress-responsive interface modification layer is 3.0 μm.

[0120] The aqueous zinc-ion button battery prepared in Example 11 is tested by constant current charge and discharge. The test instrument is a Neware CT-4008Tn battery test system. At a current density of 5 mA / cm 2 and an areal capacity of 1 mAh / cm 2 at 30 °C, the battery stably cycles for 115 h, and the voltage polarization during the cycling process is 74 mV, indicating that the aqueous zinc-ion button battery exhibits good cycling performance and low interfacial impedance.

[0121] Example 12

[0122] A zinc negative electrode with a stress-responsive interface modification layer, and the interface modification layer is uniformly distributed on the surface of the zinc negative electrode;

[0123] The material of the interface modification layer is polyborosiloxane with shear thickening properties; the structural general formula of the polyborosiloxane is R1-[Si(R2R3)-O] n -B-R4R5;

[0124] Among them, n represents the degree of polymerization of the -Si(R2R3)-O- unit in the polyborosiloxane molecular chain, and the value is 28;

[0125] R1 is the end group connected to Si, and R1 is vinyl;

[0126] R2 and R3 represent the side chains connected to silicon in the repeating unit, R2 is methyl, and R3 is aminopropyl;

[0127] R4 and R5 represent the side chains connected to the boron atom, R4 is hydroxyl and polysiloxane chain -[Si(R A R B )-O] n -H, and R A R B )-O] n -H in -[Si(R A 、R B and n are respectively consistent with R2, R3 and n in the structural general formula R1-[Si(R2R3)-O] n - of the polysiloxane chain;

[0128] R5 is hydroxyl and polysiloxane chain -[Si(R A R B )-O] n -H, and R A R B )-O] n -H in -[Si(R A 、R B and n are respectively consistent with R2, R3 and n in the structural general formula R1-[Si(R2R3)-O] n - of the polysiloxane chain.

[0129] In this embodiment, the polyborosiloxane is prepared according to the literature report, and the steps are as follows:

[0130] Weigh 5 g of polysiloxane precursor CH2=CH-[Si(CH3)(CH2CH2CH2NH2)-O] 28-H in a 100 mL beaker, 50.1 mL of an aqueous boric acid solution with a molar concentration of 0.05 M was added dropwise to the beaker under stirring until the addition of the boric acid solution was complete. The mass ratio of the polysiloxane precursor to boric acid was 97:3. During the addition of the boric acid solution, the rotation speed was maintained at 700 rpm and the temperature was 25 °C. After the addition of the boric acid solution was complete, with the rotation speed unchanged, the temperature was raised to 180 °C and reacted for 6 h to obtain a viscoelastic solid, which was transferred to a 50 °C atmospheric oven and kept for 12 h to remove internal bubbles and residual moisture, obtaining polyborosiloxane.

[0131] The polyborosiloxane obtained after the reaction was characterized by Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) (wavenumber range: 4000 - 350 cm -1 ), and an obvious Si-O-B characteristic peak existed at 1337 cm -1 , indicating that the polysiloxane precursor reacted with boric acid to form polyborosiloxane. A weak B-OH peak existed at 3224 cm -1 , indicating that there were still unreacted hydroxyl groups in the boric acid connected to the chain ends. It shows that the polyborosiloxane (R1-[Si(R2R3)-O] n -B-R4R5) prepared by the method was a mixture and there were three structures:

[0132]

[0133] A preparation method of a zinc negative electrode with a stress-responsive interface modification layer described in this embodiment, and the method is a solvent evaporation method;

[0134] Specifically, the method steps are as follows:

[0135] (1) Under an air atmosphere, the polyborosiloxane was added to n-hexane and stirred and dissolved at 25 °C at a rotation speed of 400 rpm for 30 min to obtain a homogeneous and transparent dispersion; the mass fraction of the polyborosiloxane in the dispersion was 0.2%;

[0136] A zinc foil with a thickness of 100 μm was polished brightly with 3000-mesh sandpaper. During this period, alcohol was used as a lubricant, and then polished with 5000-mesh sandpaper for 3 min, cut into a disk with a diameter of 11 mm, and the zinc sheet was evenly flattened with the bottom of a glass bottle;

[0137] (2) 20 μL of the dispersion was evenly dropped on the surface of the zinc sheet, and then placed in a 50 °C oven and dried under reduced pressure for 6 h to volatilize n-hexane, obtaining the zinc metal negative electrode with a stress-responsive polyborosiloxane interface modification layer described in this example.

[0138] An aqueous zinc ion battery, and the aqueous zinc ion battery is a zinc ion soft-pack battery, which is composed of a positive electrode, a negative electrode, a separator, and an electrolyte;

[0139] Among them, the negative electrode is the zinc negative electrode with a stress-responsive interface modification layer described in this embodiment;

[0140] The positive electrode material is lithium manganate;

[0141] The separator material is glass fiber;

[0142] The electrolyte is an aqueous solution of zinc sulfate with a molar concentration of 1M.

[0143] The zinc negative electrode with a stress-responsive interface modification layer prepared in Example 12 was characterized by scanning electron microscopy. The test results show that the thickness of the stress-responsive interface modification layer is 0.27 μm.

[0144] The aqueous zinc-ion soft-pack battery prepared in Example 12 was tested for constant current charge and discharge. The test instrument was a Neware CT-4008Tn battery test system. At 30 °C and a current density of 5 mA / cm 2 and an areal capacity of 1 mAh / cm 2 , the battery stably cycled for 90 h, and the voltage polarization during the cycling process was 70 mV, indicating that the aqueous zinc-ion soft-pack battery also exhibited good cycling performance and low interfacial impedance.

[0145] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A zinc negative electrode with a stress-responsive interface modification layer, characterized in that: The thickness of the interface modification layer is 0.1 μm to 20 μm, and the interface modification layer is uniformly distributed on the surface of the zinc negative electrode; The material of the interface modification layer is a polyborosiloxane with a structural general formula of R1-[Si(R2R3)-O] n -B-R4R5, where n represents the degree of polymerization of the -Si(R2R3)-O- units in the polyborosiloxane molecular chain, and takes a positive integer value of 10 to 150; R1 is the end group connected to Si, and R1 is methyl, hydroxyl, vinyl or a siloxane chain; R2 and R3 represent the side chains connected to silicon in the repeating unit, and R2 and R3 are independently hydrogen, methyl, aminopropyl or phenyl respectively; R4 and R5 represent side chains connected to boron atoms, and R4 and R5 are each independently at least one of a hydroxyl group, a β-cyclodextrin molecular chain, and a polysiloxane chain; the structural general formula of the polysiloxane chain is R1’-[Si(R2’R3’)-O] n -, where R2’, R3’ and n are respectively consistent with R2, R3 and n in the structural general formula of the polyborosiloxane, and R1’ is methyl, vinyl, hydroxyl or -[Si(R A R B )-O] n -H, and the R A R B )-O] n -H, and the R A , R B and n in -H are respectively consistent with R2’, R3’ and n in the structural general formula of the polysiloxane chain.

2. The zinc negative electrode with a stress-responsive interfacial modification layer according to claim 1, wherein: The thickness of the interface modification layer is 1 μm to 12 μm.

3. The zinc negative electrode with a stress-responsive interface modification layer according to claim 1 or 2, characterized in that: In the structural general formula of the polyborosiloxane, the value of n is a positive integer from 28 to 140.

4. The zinc negative electrode with a stress-responsive interface modification layer according to claim 3, characterized in that: In the structural general formula of the polyborosiloxane, the value of n is a positive integer from 30 to 80.

5. The zinc negative electrode with a stress-responsive interface modification layer according to claim 1, characterized in that: The interface modification layer further contains a zinc salt or an organic macromolecular material with zinc ion transport characteristics; in the interface modification layer, the mass fraction of the zinc salt or the organic macromolecular material is 1% to 50%; The zinc salt is at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc bis(trifluoromethanesulfonate) and zinc bis(trifluoromethanesulfonimide); The organic macromolecular material with zinc ion transport characteristics is at least one of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and phenazine; 6. A method for preparing a zinc negative electrode with a stress-responsive interfacial modification layer as described in any one of claims 1 to 5, characterized in that: The method is the solvent evaporation method, and the steps are as follows: (1) Under an air atmosphere, completely dissolve the polyborosiloxane in a diluent to form a homogeneous and transparent dispersion; In the dispersion, the mass fraction of the polyborosiloxane is 1% to 10%; The diluent is at least one of petroleum ether, n-hexane, cyclohexane, carbon disulfide, carbon tetrachloride, benzene, toluene, dichloroethane, dichloromethane, chloroform, diphenyl ether, ether and tetrahydrofuran; (2) Uniformly disperse the dispersion on the surface of the metal zinc negative electrode, and dry it at normal pressure or reduced pressure until the diluent completely volatilizes to form the interface modification layer with the above thickness on the surface of the zinc negative electrode.

7. An aqueous zinc ion battery, characterized in that: The aqueous zinc ion battery is a button cell or a soft package cell, and the zinc ion battery is composed of a positive electrode, a negative electrode, a separator and an electrolyte; 8. The aqueous zinc-ion battery according to claim 7, characterized in that: Among them, the negative electrode is the zinc negative electrode with a stress-responsive interface modification layer according to any one of claims 1 to 5. The positive electrode material of the positive electrode is at least one of vanadium-based materials, manganese-based materials, iron-based materials and sulfide materials; the vanadium-based materials include vanadium oxides or hydrated vanadium oxides; the manganese-based materials include manganese oxides; the iron-based materials include iron oxides; the sulfide materials include molybdenum disulfide or manganese sulfide; The separator material is glass fiber or cellulose; The electrolyte is an aqueous zinc salt solution or a mixed solution of a zinc salt and a neutral salt; among them, the zinc salt is at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc bis(trifluoromethanesulfonate) and zinc bis(trifluoromethanesulfonimide); the neutral salt includes lithium salts, sodium salts or potassium salts.

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