Preparation method of zinc metal battery negative electrode protection layer for regulating and controlling double electric layers

Abstract

The invention relates to the technical field of zinc metal battery negative electrodes, in particular to a preparation method of a zinc metal battery negative electrode protective layer capable of regulating and controlling double electric layers, which comprises the following steps: pre-roasting commercial diatomite at a certain temperature, immersing into an alkali solution, fully stirring for reaction, washing to be neutral, and drying; roasting the dried diatomite again, removing impurities and residual alkali, and sieving for later use; fully mixing the treated diatomite with a binder polyvinylidene fluoride and a conductive agent Super-P, and adjusting the concentration of the slurry by using a solvent N-methyl pyrrolidone; constructing the slurry on a zinc foil in a spin coating manner to obtain a zinc metal battery negative electrode; the zinc metal battery negative electrode protective layer is provided with micron / nano holes serving as zinc ion migration channels, in addition, polar bonds, namely Si-O bonds and holes, constructed by a diatomite roasting and alkali treatment process can synergistically adjust a double electrode layer on the surface of a zinc negative electrode, so that the zinc ion desolvation process is accelerated, and the cycle life is greatly prolonged. The preparation process is extremely low in cost and suitable for large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of metal batteries, and in particular to a method for preparing a negative electrode protective layer of a zinc metal battery with a double electrical layer. Background Art

[0002] Zinc metal batteries have attracted the attention of researchers due to their inherent safety and low cost. However, zinc metal batteries suffer from corrosion, passivation, hydrogen evolution and severe dendrite problems, which result in their short lifespan and limit their large-scale energy storage applications.

[0003] Although researchers have tried to alleviate the above problems by constructing artificial protective layers, these strategies are mostly limited to solving corrosion and inhibiting dendrites, and usually use porous or layered inorganic materials as artificial protective layers to guide zinc ion deposition, with a single idea and method. This is not conducive to solving the deeper contradictions of zinc metal batteries. In the conventional aqueous electrolyte zinc sulfate, zinc metal batteries will instantly form an electrical double layer (EDL) on the surface of zinc metal during the charge and discharge process. The inner Helmholtz layer (IHP) close to the inside of the zinc foil accommodates water dipoles and sulfate ions, while the hydrated zinc ions ([Zn(H2O)6] 2+ ) in the outer Helmholtz layer and the diffusion layer (DL). When the zinc metal battery is charged and discharged, water molecules continuously react in the IHP and are continuously replenished from the OHP. The generated hydroxyl (OH-) reacts with the large amount of sulfate (SO4 2- ) reacts quickly to form an insulating and inhomogeneous Zn4SO4(OH) 6-x The H2O byproduct, in addition, has a strong repulsive force between the EDL of zinc deposits, causing the deposits to be dispersed and loose plate-like, which will aggravate this phenomenon in future electrical cycles.

[0004] Therefore, it is particularly important to design a negative electrode protective layer for zinc metal batteries that can inhibit hydrogen evolution and corrosion by regulating the electric double layer (EDL) and accelerate the dissolution of zinc ions. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a negative electrode protective layer of a zinc metal battery that regulates a double electric layer, aiming to design a negative electrode protective layer for a zinc metal battery that inhibits corrosion and dendrites by synergistically regulating the double electric layer through chemical bonds and pores.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a negative electrode protective layer of a zinc metal battery with a double electric layer, comprising the following steps:

[0007] S1 Pre-calcined the commercial diatomite at a certain temperature, then immersed in an alkaline solution of a certain concentration, placed in a shaker for several hours, washed and neutralized, then calcined for the second time, and sieved for later use.

[0008] S2: fully mix the sieved diatomaceous earth, the binder polyvinylidene fluoride, and the conductive agent Super-P, and adjust the slurry concentration with the solvent N-methylpyrrolidone.

[0009] S3 constructs the above slurry on the cut zinc foil by gentle spin coating, and obtains the zinc metal battery negative electrode after drying.

[0010] The calcination temperature is 350°C for 1 hour; the concentration of the alkaline solution is 2-4 mol / L, and the mass ratio of the alkaline solution to diatomaceous earth is 2:1; the alkaline solution can be any one of potassium hydroxide and sodium hydroxide.

[0011] The solution in step S1 is shaken in a shaker for 2-12 hours, but not violently, and the diatomaceous earth is ensured not to settle, so as to ensure the intact morphology of the diatomaceous earth.

[0012] Wherein, the shaking frequency of the shaking table in step S1 is 50-100 rpm.

[0013] The mass ratio of the diatomaceous earth, the binder polyvinylidene fluoride, and the conductive agent Super-P in step S2 is 1-2.5 g: 0.3-1.67 g: 0.3-0.83 g. The amount of the solvent N-methylpyrrolidone used is 3-10 mL.

[0014] The rotation speed of the spin coater in step S3 is 100-500 r / min.

[0015] The slurry is dripped onto one side of the cut zinc foil and is spin-coated by a spin coater, and after drying, a zinc metal negative electrode protective layer is obtained, comprising:

[0016] The cut zinc foil is fixed on a spin coater, the slurry of a certain viscosity is dripped on the zinc foil, and the slurry is spin-coated at a certain speed, and repeated twice to fully build on the zinc foil. The other side of the zinc foil is wiped clean with a dust-free cloth, and the zinc foil is naturally left to stand for 2 hours. After the protective layer is built on the zinc foil, the zinc foil with the protective layer is placed in an oven and dried at 60°C for 12 hours to obtain the negative electrode of the zinc metal battery.

[0017] The present invention discloses a method for preparing a negative electrode protective layer of a zinc metal battery for regulating a double electric layer, wherein commercial diatomaceous earth is roasted at a certain temperature, the pores are initially expanded, and then the roasted diatomaceous earth is soaked in an alkaline solution, shaken on a shaker for several hours, washed to neutrality, and then roasted for the second time, and the treated diatomaceous earth is sieved for use. The treated diatomaceous earth, the binder polyvinylidene fluoride, and the conductive agent Super-P are mixed in a certain proportion, and the viscosity of the slurry is adjusted with a solvent N-methylpyrrolidone. The processed and cut zinc foil is fixed on a spin coater, the slurry of a certain viscosity is dripped on the zinc foil, and the slurry is spin-coated at a certain speed, repeated twice, and fully constructed on the zinc foil, and the other side of the zinc foil is wiped clean with a dust-free cloth, and naturally left to stand for 2 hours. After the protective layer is constructed on the zinc foil, the zinc foil with the protective layer is placed in an oven and dried at 60°C for 12 hours to obtain the negative electrode protective layer of the zinc metal battery. The zinc metal battery negative electrode has a uniform ion channel, and the zinc metal battery negative electrode protective layer has micron / nanopores as zinc ion migration channels. In addition, the chemical bonds (Si-O bonds) and pores constructed by the calcination and alkali treatment of diatomaceous earth processes can coordinately regulate the double electric layer on the surface of the zinc negative electrode, thereby accelerating the desolvation process of zinc ions and greatly improving the cycle life. The preparation process cost is extremely low and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 (a) Schematic diagram of the double layer of bare zinc, and (b) a schematic diagram of the regulation of the double layer by the zinc metal negative electrode protective layer.

[0020] Figure 2 (a) is the SEM image of commercial diatomite, and (b) is the SEM image of diatomite after calcination and alkali treatment.

[0021] Figure 3 This is a cross-sectional SEM image of the negative electrode protective layer of a zinc metal battery.

[0022] Figure 4 is 1mA cm -2 , 1mAh cm -2 Symmetrical battery long-term cycle test diagram under current density.

[0023] Figure 5 (a) The surface current density is 0.5 mA cm -2Coulombic efficiency diagram of zinc-copper half-cell under (a), half-cell life diagram of bare zinc, and half-cell life diagram of zinc metal battery negative electrode protective layer.

[0024] Figure 6 It is a flow chart of a method for preparing a negative electrode protective layer of a zinc metal battery for regulating a double electric layer provided by the present invention. DETAILED DESCRIPTION

[0025] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0026] See also Figures 1 to 6 In a first aspect, the present invention provides a method for preparing a negative electrode protective layer of a zinc metal battery with a double electric layer, comprising the following steps:

[0027] S1 pre-calcined commercial diatomaceous earth, then mixed with alkaline solution, shaken on a shaker for several hours, washed to neutrality, calcined twice, and sieved for later use;

[0028] Specifically, the calcination temperature is 350° C. for 1 hour; the concentration of the alkaline solution is 2-4 mol / L, and the mass ratio of the alkaline solution to diatomaceous earth is 2:1; the alkaline solution can be any one of potassium hydroxide and sodium hydroxide; the mixed solution is shaken in a shaker for 2-12 hours, not violently, and the diatomaceous earth is ensured not to settle, so as to ensure the integrity of the diatomaceous earth morphology, and the shaking frequency is 50-100 rpm.

[0029] S2: mixing the diatomaceous earth with polyvinylidene fluoride and Super-P, and adjusting the slurry concentration with N-methylpyrrolidone;

[0030] Specifically, the mass ratio of the diatomite, the binder polyvinylidene fluoride, and the conductive agent Super-P is 1-2.5 g: 0.3-1.67 g: 0.3-0.83 g. The amount of the solvent N-methylpyrrolidone used is 3-10 mL.

[0031] S3 The above slurry is constructed on the cut zinc foil by gentle spin coating, and after drying, the zinc metal battery negative electrode is obtained, and the battery is assembled.

[0032] Specifically, the slurry is dripped onto one side of the cut zinc foil, and is spin-coated by a spin coater, and after drying, a zinc metal negative electrode protective layer is obtained, comprising:

[0033] Fix the cut zinc foil on the spin coater, drip the slurry of a certain viscosity on the zinc foil, and spin coat at a certain speed, repeat twice, fully build on the zinc foil, wipe the other side of the zinc foil with a dust-free cloth, let it stand naturally for 2 hours, after building a protective layer on the zinc foil, put the zinc foil with the protective layer into an oven, dry it at 60℃ for 12 hours, and obtain the negative electrode of the zinc metal battery. The certain speed is 100-500r / min

[0034] Through the calcination and alkaline etching process, the negative electrode protective layer of the zinc metal battery has micron / nano pores and polar Si-O bonds, which can coordinately regulate the double electric layer. The thickness of the protective layer can be controlled by spin coating, and the spin coating thickness is about 39.1 to 60μm.

[0035] The beneficial effect of the present invention is that the present invention is a method for preparing a negative electrode protective layer of a zinc metal battery that regulates the double electric layer. Through the roasting and alkaline etching process, the negative electrode protective layer has micron / nano pores, constructs ion channels, and accelerates ion migration. In addition, this process also enables a large number of Si-O bonds to be obtained on the negative electrode protective layer, which cooperates with special pores to regulate the double electric layer, thereby inhibiting side reactions and greatly improving the cycle life. It is worth noting that the protective layer is constructed by a gentle spin coating method, which greatly ensures the integrity of the diatomite morphology and retains the special structure and specific surface area of ​​diatomite. Its preparation process is also low-cost and suitable for large-scale production.

[0036] Specifically:

[0037] (1) The present invention provides a zinc metal battery negative electrode protective layer for regulating the double electric layer. The negative electrode protective layer for the zinc metal battery with a double electric layer can be prepared by calcining and alkali treating commercial diatomaceous earth, drying it, mixing it with a binder polyvinylidene fluoride and a conductive agent Super-P to form a slurry, and then gently spin coating the slurry on a zinc foil. The preparation cost is low and can be prepared on a large scale.

[0038] (2) The zinc metal battery negative electrode protective layer for regulating the double electric layer of the present invention is functionalized in that the zinc metal battery negative electrode protective layer for regulating the double electric layer has micron / nanopores to construct a zinc ion migration channel with a mobility of 0.5; the polar Si-O bonds on the protective layer cooperate with the special pore structure to regulate the double electric layer, further accelerating the zinc desolvation process, and the desolvation energy is 35 kJ mol -1 , achieving the planar deposition of zinc ions. The schematic diagram of the protective layer regulating the double electrical layer is shown in Figure 1 In addition, the gentle spin coating process makes the thickness of the protective layer controllable and ensures the complete functionalization of the diatomite protective layer.

[0039] Embodiment 1

[0040] A zinc metal battery negative electrode protective layer for regulating double electric layers, the preparation method of which comprises the following steps:

[0041] (1) Place commercial diatomite in a muffle furnace and pre-bake at 350°C for 1 hour. Then add 1g of pre-bake diatomite to 2mol / L sodium hydroxide solution. The mass ratio of sodium hydroxide solution to diatomite is 2:1. Place the solution in a shaker and shake at a frequency of 100 rpm for 6 hours. Wash with deionized water and alcohol until neutral. Place the dried diatomite in a muffle furnace again and bake at 350°C for 1 hour. Sieve to obtain the treated diatomite. SEM images of commercial diatomite and treated diatomite are shown in Figure 2

[0042] (2) Weigh 1 g of the treated diatomaceous earth described in (1), mix it evenly with 0.3 g of binder polyvinylidene fluoride and 0.3 g of conductive agent Super-P, and adjust the slurry viscosity with 10 ml of solvent N-methylpyrrolidone. After sufficient stirring, a prefabricated slurry is obtained.

[0043] (3) The prefabricated slurry described in (2) is dripped onto the cut zinc foil, and the slurry is constructed on the zinc foil by a spin coater, and the spin coating is repeated twice at a spin coating rate of 500 r / min. After drying, a diatomite artificial protective layer negative electrode is obtained. The thickness of the diatomite artificial protective layer is about 39.1 μm. The scanning electron microscope image of the cross section of the diatomite artificial protective layer negative electrode is shown in Figure 3 .

[0044] (4) A symmetrical battery was assembled by assembling the zinc metal negative electrode coated with a diatomaceous earth artificial protective layer after curing as described in (3) at 1 mA cm -2 , 1mAh cm -2 The lifespan can reach 846h at the current density, and the voltage hysteresis is 42.0mV. Figure 4 The zinc foil coated with diatomite artificial protective layer was assembled with copper foil into a half-cell, and the current was 0.5 mA cm -2 Under the current density condition, the charge and discharge test was carried out, the cycle life was 935h, the growth overpotential was 47.0mV, and the results are shown in Figure 5 The preparation process of the negative electrode protective layer of zinc metal battery with double electrical layer regulation is shown in Figure 6 .

[0045] Embodiment 2

[0046] A zinc metal battery negative electrode protective layer for regulating double electric layers, the preparation method of which comprises the following steps:

[0047] (1) Commercial diatomaceous earth is placed in a muffle furnace and pre-calcined at 350°C for 1 hour. Then, 1 g of the pre-calcined diatomaceous earth is added to a 2 mol / L potassium hydroxide solution, and the mass ratio of the potassium hydroxide solution to the diatomaceous earth is 2:1. The solution is placed in a shaker and shaken at a frequency of 100 rpm for 6 hours. The diatomaceous earth is washed with deionized water and alcohol until it is neutral. The dried diatomaceous earth is placed in a muffle furnace again and calcined at 350°C for 1 hour. The treated diatomaceous earth is obtained after sieving.

[0048] (2) Weigh 1 g of the treated diatomaceous earth described in (1), mix it evenly with 0.3 g of binder polyvinylidene fluoride and 0.3 g of conductive agent Super-P, and adjust the slurry viscosity with 10 ml of solvent N-methylpyrrolidone. After sufficient stirring, a prefabricated slurry is obtained.

[0049] (3) dripping the prefabricated slurry described in (2) onto the cut zinc foil, and using a spin coater to build the slurry onto the zinc foil, repeating the spin coating twice at a spin coating rate of 500 r / min, and obtaining a diatomite artificial protective layer negative electrode after drying. The thickness of the diatomite artificial protective layer is about 40 μm.

[0050] (4) A symmetrical battery assembled with the zinc metal battery negative electrode coated with a diatomaceous earth artificial protective layer after curing as described in (3) at 1 mA cm -2 , 1mAh cm -2 The lifespan can reach 700 h at the current density, and the voltage hysteresis is 39.0 mV. The zinc foil coated with diatomite artificial protective layer and the copper foil are assembled into a half-cell. -2 Under the condition of current density, charge and discharge test was carried out, the cycle life was 830h and the growth overpotential was 41.0mV.

[0051] Embodiment 3

[0052] A zinc metal battery negative electrode protective layer for regulating double electric layers, the preparation method of which comprises the following steps:

[0053] (1) Commercial diatomaceous earth is placed in a muffle furnace and pre-calcined at 350°C for 1 hour. Then, 1 g of the pre-calcined diatomaceous earth is added to a 4 mol / L sodium hydroxide solution, and the mass ratio of the sodium hydroxide solution to the diatomaceous earth is 2:1. The solution is placed in a shaker and shaken at a frequency of 100 rpm for 6 hours. The diatomaceous earth is washed with deionized water and alcohol until it is neutral. The dried diatomaceous earth is placed in a muffle furnace again and calcined at 350°C for 1 hour. The treated diatomaceous earth is obtained after sieving.

[0054] (2) Weigh 1 g of the treated diatomaceous earth described in (1), mix it evenly with 0.3 g of binder polyvinylidene fluoride and 0.3 g of conductive agent Super-P, and adjust the slurry viscosity with 10 ml of solvent N-methylpyrrolidone. After sufficient stirring, a prefabricated slurry is obtained.

[0055] (3) dripping the prefabricated slurry described in (2) onto the cut zinc foil, and using a spin coater to build the slurry onto the zinc foil, repeating the spin coating twice at a spin coating rate of 500 r / min, and obtaining a diatomite artificial protective layer negative electrode after drying. The thickness of the diatomite artificial protective layer is about 39.1 μm.

[0056] (4) A symmetrical battery assembled with the zinc metal battery negative electrode coated with a diatomaceous earth artificial protective layer after curing as described in (3) at 1 mA cm -2 , 1mAh cm -2 The lifespan can reach 450 h at the current density, and the voltage hysteresis is 38.0 mV. The zinc foil coated with diatomite artificial protective layer and the copper foil are assembled into a half-cell. -2 Under the current density condition, the charge and discharge test was carried out, the cycle life was about 610h, and the growth overpotential was 40.2mV.

[0057] Embodiment 4

[0058] A zinc metal battery negative electrode protective layer for regulating double electric layers, the preparation method of which comprises the following steps:

[0059] (1) Commercial diatomaceous earth is placed in a muffle furnace and pre-calcined at 350°C for 1 hour. Then, 1 g of the pre-calcined diatomaceous earth is added to a 2 mol / L sodium hydroxide solution, and the mass ratio of the sodium hydroxide solution to the diatomaceous earth is 2:1. The solution is placed in a shaker and shaken at a frequency of 100 rpm for 12 hours. The diatomaceous earth is washed with deionized water and alcohol until it is neutral. The dried diatomaceous earth is placed in a muffle furnace again and calcined at 350°C for 1 hour. The treated diatomaceous earth is obtained after sieving.

[0060] (2) Weigh 1 g of the treated diatomaceous earth described in (1), mix it evenly with 0.3 g of binder polyvinylidene fluoride and 0.3 g of conductive agent Super-P, and adjust the slurry viscosity with 10 ml of solvent N-methylpyrrolidone. After sufficient stirring, a prefabricated slurry is obtained.

[0061] (3) dripping the prefabricated slurry described in (2) onto the cut zinc foil, and using a spin coater to build the slurry onto the zinc foil, repeating the spin coating twice at a spin coating rate of 500 r / min, and obtaining a diatomite artificial protective layer negative electrode after drying. The thickness of the diatomite artificial protective layer is about 38 μm.

[0062] (4) A symmetrical battery assembled with the zinc metal battery negative electrode coated with a diatomaceous earth artificial protective layer after curing as described in (3) at 1 mA cm -2 , 1mAh cm -2The lifespan can reach 530h at the current density, and the voltage hysteresis is 37.6mV. The zinc foil coated with diatomite artificial protective layer and the copper foil are assembled into a half-cell. -2 Under the current density condition, the charge and discharge test was carried out, the cycle life was about 665h, and the growth overpotential was 39.0mV.

[0063] Embodiment 5

[0064] A zinc metal battery negative electrode protective layer for regulating double electric layers, the preparation method of which comprises the following steps:

[0065] (1) Commercial diatomaceous earth is placed in a muffle furnace and pre-calcined at 350°C for 1 hour. Then, 1 g of the pre-calcined diatomaceous earth is added to a 2 mol / L sodium hydroxide solution, and the mass ratio of the sodium hydroxide solution to the diatomaceous earth is 2:1. The solution is placed in a shaker and shaken at a frequency of 100 rpm for 6 hours. The diatomaceous earth is washed with deionized water and alcohol until it is neutral. The dried diatomaceous earth is placed in a muffle furnace again and calcined at 350°C for 1 hour. The treated diatomaceous earth is obtained after sieving.

[0066] (2) Weigh 1 g of the treated diatomaceous earth described in (1), mix it evenly with 0.3 g of binder polyvinylidene fluoride and 0.3 g of conductive agent Super-P, and adjust the slurry viscosity with 10 ml of solvent N-methylpyrrolidone. After sufficient stirring, a prefabricated slurry is obtained.

[0067] (3) dripping the prefabricated slurry described in (2) onto the cut zinc foil, and using a spin coater to form the slurry onto the zinc foil, repeating the spin coating twice at a spin coating rate of 100 r / min, and obtaining a diatomite artificial protective layer negative electrode after drying. The thickness of the diatomite artificial protective layer is about 60 μm.

[0068] (4) A symmetrical battery assembled with the zinc metal battery negative electrode coated with a diatomaceous earth artificial protective layer after curing as described in (3) at 1 mA cm -2 , 1mAh cm -2 The lifespan can reach 700h at the current density, and the voltage hysteresis is 45.0mV. The zinc foil coated with diatomite artificial protective layer and the copper foil are assembled into a half-cell. -2 Under the current density condition, the charge and discharge test was carried out, the cycle life was about 630h, and the growth overpotential was 49.0mV.

[0069] Comparative Example

[0070] Comparative Example 1

[0071] The difference from Example 1 is that untreated diatomaceous earth is directly used as the negative electrode protective layer of the zinc metal battery, and the preparation method thereof comprises the following steps:

[0072] (1) 1 g of commercial diatomite was weighed and uniformly mixed with 0.3 g of binder polyvinylidene fluoride and 0.3 g of conductive agent Super-P, and 10 ml of solvent N-methylpyrrolidone was used to adjust the slurry viscosity. After sufficient stirring, a prefabricated slurry was obtained.

[0073] (2) dripping the prefabricated slurry described in (1) onto the cut zinc foil, and using a spin coater to form the slurry onto the zinc foil, repeating the spin coating twice at a spin coating rate of 100 r / min, and obtaining a diatomite artificial protective layer negative electrode after drying. The thickness of the diatomite artificial protective layer is about 59 μm.

[0074] (3) A symmetrical battery was assembled by coating the zinc metal battery negative electrode with a diatomaceous earth artificial protective layer after curing as described in (2) at 1 mA cm -2 , 1mAh cm -2 The lifespan can reach 415 h at the current density, and the voltage hysteresis is 45.8 mV. The zinc foil coated with diatomite artificial protective layer and the copper foil are assembled into a half-cell. -2 Under the current density condition, the charge and discharge test was carried out, the cycle life was about 330h, and the growth overpotential was 51.0mV.

[0075] Comparative Example 2

[0076] The difference from Examples 1 to 4 is that zinc foil is directly used as the negative electrode of the zinc metal battery.

[0077] Symmetric cell assembled with a negative electrode of zinc metal battery at 1 mA cm -2 , 1mAh cm -2 The lifespan can reach 224h at the current density, and the voltage hysteresis is 67mV. Figure 4 The zinc foil coated with diatomite artificial protective layer was assembled with copper foil into a half-cell, and the current was 0.5 mA cm -2 Under the current density condition, the charge and discharge test was carried out, the cycle life was about 150h, and the growth overpotential was 54.0mV. Figure 5 .

[0078] The above disclosure is only a preferred embodiment of a method for preparing a zinc metal battery negative electrode with a double-electric layer-regulated protective layer of the present invention. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A zinc metal battery negative electrode protective layer for regulating double electric layer, characterized in that: The following steps are involved: S1 Pre-calcined the commercial diatomite at a certain temperature, then immersed in an alkaline solution of a certain concentration, placed in a shaker for several hours, washed and neutralized, then calcined for the second time, and sieved for later use. S2: fully mix the sieved diatomaceous earth, the binder polyvinylidene fluoride, and the conductive agent Super-P, and adjust the slurry concentration with the solvent N-methylpyrrolidone. S3 constructs the above slurry on the cut zinc foil by gentle spin coating, and obtains the zinc metal battery negative electrode after drying.

2. The method for preparing a negative electrode protective layer of a zinc metal battery with a double electric layer as claimed in claim 1, characterized in that: The calcination temperature is 350°C for 1 hour; the concentration of the alkaline solution is 2-4 mol / L, and the mass ratio of the solution to diatomaceous earth is 1:2; the alkaline solution can be any one of potassium hydroxide and sodium hydroxide. The shaking frequency of the shaking table is 50-100 rpm.

3. The method for preparing a negative electrode protective layer of a zinc metal battery with a double electric layer control as claimed in claim 2, characterized in that: The mass ratio of the diatomite, the binder polyvinylidene fluoride, and the conductive agent Super-P is 1-2.5 g: 0.3-1.67 g: 0.3-0.83 g. The amount of the solvent N-methylpyrrolidone used is 3-10 mL.

4. The method for preparing a negative electrode protective layer of a zinc metal battery with a double electric layer control as claimed in claim 3, characterized in that: The solution in step S1 is shaken in a shaker for 2-12 hours, but not violently, and the diatomaceous earth is ensured not to settle, so as to ensure the intact morphology of the diatomaceous earth. The rotation speed of the spin coater in step S3 is 100-500 r / min.

5. The method for preparing a negative electrode protective layer of a zinc metal battery with a double electric layer control as claimed in claim 4, characterized in that: The slurry is dripped onto one side of the cut zinc foil and spin-coated by a spin coater, and after drying, a zinc metal negative electrode protective layer is obtained, comprising: The cut zinc foil is fixed on a spin coater, the slurry of a certain viscosity is dripped on the zinc foil, and spin-coated at a certain rotation speed, which is repeated twice to fully build on the zinc foil, and the other side of the zinc foil is wiped clean with a dust-free cloth, and allowed to stand naturally for 2 hours. After a protective layer is built on the zinc foil, the zinc foil with the protective layer is put into an oven and dried at 60°C for 12 hours to obtain a negative electrode of a zinc metal battery.

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