Zinc powder air battery containing mixed corrosion inhibitor and preparation method thereof

Abstract

The invention discloses a zinc powder air battery containing a mixed corrosion inhibitor and a preparation method of the zinc powder air battery. The preparation method of the zinc powder air battery specifically comprises the following steps: the zinc powder, the micro-nano conductive carbon material and the E-44 type epoxy resin form the negative electrode layer, and the negative electrode layer and the air positive electrode are assembled in the liquid zinc powder air battery. In the discharging process, a proper amount of dodecyl dimethyl betaine is additionally added into the alkaline electrolyte. Dodecyl dimethyl betaine is spontaneously adsorbed on the surface of the hydrophobic negative electrode layer, so that the wettability of the electrode is improved. A dodecyl hydrophobic group in dodecyl dimethyl betaine is compatible with a benzene ring hydrophobic group of E-44 type epoxy resin, and a hydrophilic group carboxyl is compatible with Zn < 2 + >. The corrosion effect of the zinc powder is slowed down by compounding the two components, the discharge voltage of a 100 mA cm <-2 > zinc powder air battery reaches 0.78 V, the specific capacity is 550 mAh / g, and the discharge voltage reaches 77% of that of a zinc sheet. According to the mixed corrosion inhibitor and the zinc powder air battery provided by the invention, the problems of corrosion, passivation and the like caused by direct contact between the zinc powder and an electrolyte are greatly relieved, so that the utilization rate of the zinc powder and the discharge performance of the zinc air battery are improved.

Description

Technical Field

[0001] The invention relates to the technical field of zinc powder air batteries, and in particular to a zinc powder air battery containing a mixed corrosion inhibitor and a preparation method thereof. Background Art

[0002] Zinc powder air batteries have great potential in the development of zinc air batteries due to their advantages such as low cost, high utilization rate and good processability, and are expected to promote further breakthroughs and developments in battery technology. However, zinc powder electrodes have serious voltage polarization and hydrogen evolution side reactions, which are key factors leading to battery failure. Since zinc has a greater negative reduction potential than hydrogen, metallic zinc is thermodynamically unstable in alkaline solutions, resulting in the precipitation of hydrogen. Under alkaline conditions, the conjugate corrosion reaction process on the zinc negative electrode is as follows:

[0003]

[0004] The main measure to reduce the rate of hydrogen evolution corrosion is to add inorganic or organic corrosion inhibitors to the electrode or electrolyte to enhance the anode hydrogen evolution overpotential or form a surface adsorption layer. Inorganic corrosion inhibitors mainly include metal elements, metal oxides, metal hydroxides and salts with high chemical stability and high hydrogen evolution overpotential. Organic corrosion inhibitors such as polyethylene glycol and polyaniline can also be used to inhibit the occurrence of corrosion reactions. For example, in zinc-air batteries, polyaniline is adsorbed on the zinc active material to isolate it from the aqueous electrolyte, which can inhibit the corrosion reaction of the battery.

[0005] The combined use of corrosion inhibitors can achieve better results than a single corrosion inhibitor. For example, inhibitors such as Tween-20 and imidazole can be used together with polyethylene glycol to produce a synergistic effect on the inhibition of zinc corrosion. In addition, zincate and silicate can work together to form a stable silicon-zinc compound film, reduce the corrosion of the zinc electrode, and improve the performance and service life of the battery. However, zinc powder air batteries still have problems with poor stability and severe corrosion. Summary of the invention

[0006] The technical problem to be solved by the present invention is to invent a zinc powder air battery containing a mixed corrosion inhibitor and a preparation method thereof in view of the above-mentioned defects of the prior art, aiming to solve the problem of poor stability and severe corrosion of the zinc powder negative electrode of the zinc air battery in the prior art.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0008] A method for preparing a negative electrode of a zinc powder-air battery containing a mixed corrosion inhibitor comprises the following steps:

[0009] Dissolving E-44 epoxy resin in a volatile solvent, adding a mixture of zinc powder and micro-nano conductive carbon material, and stirring to obtain a zinc powder slurry;

[0010] Spin coating the zinc powder slurry onto a porous conductive substrate, and drying to obtain a negative electrode layer;

[0011] A zinc powder air battery is assembled based on an air positive electrode, the negative electrode layer and an alkaline electrolyte; wherein the alkaline electrolyte includes: a strong base, dodecyl dimethyl betaine (denoted as BS-12) and water; the ratio of the E-44 epoxy resin, the zinc powder, the micro-nano conductive carbon material and the dodecyl dimethyl betaine is: 0.5-2g: 2g: 25-200mg: 5-50μL.

[0012] E-44 epoxy resin is a high molecular synthetic material with excellent performance. Its molecular formula is as follows (n=1~2.8):

[0013]

[0014] E-44 epoxy resin has good adhesion, alkali resistance and high mechanical strength. Since the porous conductive substrate has a three-dimensional porous structure, E-44 epoxy resin will penetrate into the pores of the porous conductive substrate and fix the zinc powder on the surface and pores of the porous conductive substrate like a "hook" through mechanical interlocking. E-44 epoxy resin has a low molecular weight and rheological properties. Specifically, it is semi-solid and has certain liquid behavior, which is conducive to Zn 2+ In addition, due to the inherent hydrophobicity of E-44 epoxy resin, it can prevent zinc powder from directly contacting OH - , H 2 O contact, thereby reducing the occurrence of self-corrosion reaction and playing a good corrosion inhibition effect.

[0015] A mixture of dried zinc powder, E-44 epoxy resin and micro-nano conductive carbon material is used as the negative electrode layer, and a certain amount of dodecyl dimethyl betaine BS-12 is added to the alkaline electrolyte. The molecular formula is as follows:

[0016]

[0017] The BS-12 molecule of dodecyl dimethyl betaine contains a hydrophobic dodecyl long chain and a hydrophilic group (carboxyl and quaternary ammonium salt group). The dodecyl hydrophobic long chain has an affinity with the benzene ring in the hydrophobic E-44 epoxy resin molecule. The dodecyl hydrophobic chain can effectively repel H 2 O molecules and high concentrations of OH - , further inhibiting corrosion. The carboxyl group of the hydrophilic group and Zn 2+ It has an affinity effect, can solvate zinc ions and improve the wettability of the negative electrode interface (the contact angle becomes smaller), thereby reducing voltage polarization.

[0018] As a comparison, the present invention also uses betaine without dodecyl hydrophobic long chain (denoted as BS) and dodecane without hydrophilic group (denoted as DD) as additives to replace dodecyl dimethyl betaine BS-12. Betaine BS without hydrophobic group can be electrostatically adsorbed on the surface of the negative electrode layer through the hydrophilic charged group, but due to the lack of hydrophobic group, it cannot effectively squeeze out the H on the surface of the negative electrode layer. 2 O molecules and high concentrations of OH - , resulting in self-corrosion of zinc powder and reduction of capacity and voltage. Although DD without hydrophilic groups as an additive has a certain hydrophobicity, it prevents H 2 O molecules and OH - However, DD lacks hydrophilic groups and has a low affinity for zinc ions, which leads to difficulty in ion transfer, large internal resistance of the battery, and obvious initial voltage polarization.

[0019] As a surfactant, dodecyl dimethyl betaine BS-12 has an optimal adsorption concentration when adsorbed on the negative electrode layer. An appropriate amount of dodecyl dimethyl betaine BS-12 can not only have a good corrosion inhibition effect, but also improve the wettability of the electrode surface.

[0020] The ratio of the E-44 epoxy resin, the zinc powder, the micro-nano conductive carbon material, and the dodecyl dimethyl betaine is: 0.5-1.5 g: 2 g: 50 mg: 10-50 μL.

[0021] Specifically, when the ratio of each raw material is within an appropriate range, the zinc powder air battery has better performance.

[0022] Preferably, the ratio of the E-44 epoxy resin, the zinc powder, the micro-nano conductive carbon material, and the dodecyl dimethyl betaine is: 1 g: 2 g: 50 mg: 10 μL.

[0023] When the micro-nano conductive carbon material is mixed with zinc powder, the ratio should be controlled within a certain range. When the amount of micro-nano conductive carbon material is too much, the activity of zinc powder and battery capacity will be reduced, while when the amount of micro-nano conductive carbon material is too little, the internal resistance of the battery will increase and polarization will be serious. In addition, considering the low conductivity of E-44 epoxy resin as a binder, the amount added needs to be in a certain relationship with the mixture of zinc powder and micro-nano conductive carbon material.

[0024] The stirring time is 0.5 to 3 hours. The stirring time in the process can affect the state of the zinc paste settling from the solution. During the stirring process, the E-44 epoxy resin will spontaneously adsorb on the surface of the zinc powder mixture, increase the surface tension, aggregate and precipitate. A shorter stirring time may cause the zinc powder to not be completely precipitated, resulting in loss, while a longer stirring time will lead to a decrease in overall conductivity caused by excessive adsorption of the E-44 epoxy resin.

[0025] The mesh number of the zinc powder used is 100-800 mesh (the diameter of the zinc powder is 18-150 microns). The mesh number of the zinc powder indicates the number of holes on the screen per inch, which is used to reflect the size of the zinc powder particles. The larger the mesh number, the finer the zinc powder particles, which means that its reaction activity is better and the corrosion is more severe, which leads to the loss of the discharge capacity of the zinc powder. Therefore, if you need to achieve higher reaction activity and lower corrosion activity, you should choose zinc powder with a suitable pore size.

[0026] Due to the low conductivity of the E-44 epoxy resin, a certain amount of micro-nano conductive carbon material should be added when mixed with zinc powder. The micro-nano conductive carbon material is conductive carbon black.

[0027] Preferably, the ratio of dodecyl dimethyl betaine to the strong base is 5-50 μL:70 mL.

[0028] The zinc powder air battery, wherein the strong base is KOH; wherein the concentration of the strong base is 6 mol L -1 .

[0029] The zinc powder-air battery, wherein the air positive electrode is obtained by the following steps:

[0030] The catalyst, micro-nano conductive carbon material, polytetrafluoroethylene PVDF and volatile solvent are mixed and rolled to prepare a catalytic layer; wherein the catalyst is Pt / C and the loading amount is 1-5 mg cm -2 ;

[0031] The waterproof and breathable conductive membrane and the catalyst layer are stacked on the current collector in sequence to obtain an air positive electrode.

[0032] Specifically, the catalyst and the micro-nano conductive carbon material are placed in a mortar, and a volatile solvent (such as anhydrous ethanol) and a PVDF slurry are added, and then ground into a sheet, rolled into a thin layer, and cut to obtain a catalytic layer after drying. The role of the micro-nano conductive carbon material is to enhance the conductivity of the catalyst, the role of the volatile solvent is to make the catalyst and the micro-nano conductive carbon material mix evenly, and the role of the PVDF slurry is to make the catalyst and the micro-nano conductive carbon material form a film.

[0033] Specifically, the current collector is used to connect the catalyst layer and the external circuit. The thickness of the waterproof breathable conductive film is 0.3 to 1 mm. The waterproof breathable conductive film is used to construct a three-phase interface to prevent the electrolyte from completely permeating the catalyst in the catalyst layer and reducing its catalytic activity, while not hindering the entry of air.

[0034] In the zinc powder-air battery, the current collector extends to form a positive electrode connecting portion; and the conductive substrate in the negative electrode layer extends to form a negative electrode connecting portion.

[0035] Specifically, in order to facilitate the connection to the external circuit, a positive electrode connection portion is extended on the current collector, and a negative electrode connection portion is extended on the negative electrode, and the positive electrode connection portion and the negative electrode connection portion are used to connect to the external circuit. The waterproof and breathable conductive film and the catalyst layer in the positive electrode are both located below the liquid level of the alkaline electrolyte, and the positive electrode connection portion is located above the liquid level of the alkaline electrolyte. The negative electrode connection portion does not carry zinc powder.

[0036] Based on the air positive electrode, the negative electrode layer and the alkaline electrolyte, a zinc powder air battery is assembled, which specifically includes the following steps:

[0037] Assembling the air positive electrode to the shell; the shell has a window;

[0038] Assembling the negative electrode layer to the casing;

[0039] Alkaline electrolyte is injected into the housing.

[0040] Specifically, the positive electrode, the negative electrode layer and the alkaline electrolyte can be prepared separately, and then the positive electrode is assembled into the shell, the negative electrode layer is assembled into the shell, and the alkaline electrolyte is injected into the shell to form a zinc powder air battery.

[0041] Specifically, the positive electrode in the zinc powder air battery is an air positive electrode, which reacts with oxygen in the air, and air enters the air positive electrode from the window. The negative electrode is the negative electrode layer, and the electrolyte is an alkaline electrolyte. The zinc powder reacts with the hydroxide ions in the alkaline electrolyte.

[0042] The beneficial effects of the present invention are as follows:

[0043] 1. The zinc powder air battery prepared by the present invention benefits from the excellent bonding effect of E-44 epoxy resin. The zinc powder negative electrode can be stably discharged on the conductive substrate. The hydrophobicity of E-44 epoxy resin and the amphiphilicity of dodecyl dimethyl betaine cooperate with each other to slow down the corrosion and passivation of zinc powder in the strong alkaline electrolyte. -2 The discharge voltage of the zinc powder-air battery reached 0.78V, and the specific capacity was 550mAh / g, reaching 77% of the zinc sheet, which improved the utilization rate of zinc powder and the discharge performance of the zinc-air battery.

[0044] 2. The method of the present invention has strong controllability, does not require complicated equipment and instruments, and is suitable for large-scale industrial system application. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a preparation route map of the negative electrode of the zinc powder air battery using a mixed corrosion inhibitor in an embodiment of the present invention.

[0046] Figure 2 The negative electrode layer and E(1)C in the embodiment of the present invention B (1) / Contact angle of BS-12.

[0047] Figure 3 is the negative electrode layer in the embodiment of the present invention, E(1)C B (1)-KOH and E(1)C B (1) Infrared spectrum of BS-12-KOH.

[0048] Figure 4 The embodiment 1, the embodiment 11, the comparative example 1, the comparative example 2 and the comparative example 3 of the present invention are at 100 mA cm -2 The constant current discharge curve below.

[0049] Figure 5 The zinc powder air battery with different amounts of BS-12 added in the embodiment of the present invention at 100 mA cm -2 The constant current discharge curve below.

[0050] Figure 6 The results of the zinc powder-air battery with different amounts of E-44 epoxy resin added in the embodiment of the present invention at 20 mA cm -2 The constant current discharge curve below.

[0051] Figure 7 The zinc powder air battery with different amounts of carbon black added in the embodiment of the present invention is -2 The constant current discharge curve below.

[0052] Figure 8 It is the Tafel curve of the corrosion test results of Example 11 of the present invention and Comparative Example 1.

[0053] Fig. 9 It is the Tafel curve of the corrosion test results of Example 1 and Example 11 of the present invention.

[0054] Fig.10 It is a linear sweep voltammetric curve of the hydrogen evolution test results of Example 1 and Example 11 of the present invention.

[0055] Fig.11 1 and 2 are polarization curves and power densities of Example 1 and Comparative Example 1 in the embodiments of the present invention.

[0056] Fig.12 The 100-mesh and 800-mesh zinc powder-based air batteries in the embodiment of the present invention are -2 The constant current discharge curve below. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0058] Since zinc has a more negative reduction potential than hydrogen, metallic zinc is thermodynamically unstable in alkaline solutions, resulting in hydrogen evolution corrosion on the surface of the zinc negative electrode. Hydrogen evolution corrosion consumes electrons in the battery and reduces the battery's energy conversion efficiency. In addition, hydrogen evolution corrosion may also lead to passivation of the zinc negative electrode surface, further affecting the battery's discharge performance. The large specific surface area of ​​zinc powder exacerbates the corrosion phenomenon.

[0059] At present, the existing methods use corrosion inhibitors to enhance the anode hydrogen evolution overpotential or form a surface adsorption layer to reduce the occurrence of corrosion reactions. However, whether it is a single inorganic / organic corrosion inhibitor or a combination of multiple components, it is difficult to maintain the surface properties of zinc metal while ensuring a high corrosion inhibition efficiency. Therefore, when designing a mixed corrosion inhibitor formula, it is necessary to fully consider the interaction between corrosion inhibitors.

[0060] This application uses hydrophobic E-44 epoxy resin to form a protective layer on the surface of zinc powder to isolate OH - With H 2 O, and at the same time, its hydrophobic group (benzene ring) has an affinity with the hydrophobic group (dodecyl) of another additive. The two work together to inhibit corrosion and improve the discharge voltage and utilization rate of zinc powder. The cost is low and it is suitable for large-scale use.

[0061] Embodiment 1

[0062] (1) 1 g of E-44 epoxy resin is dissolved in 5 g of anhydrous ethanol, and a mixture of 2 g of 800-mesh zinc powder and 50 mg of Super C45 carbon black is added, and the mixture is stirred vigorously for 1 hour to obtain a zinc powder slurry; the obtained zinc powder slurry is spin-coated on a porous conductive substrate nickel foam of 70 mm (length) * 30 mm (width) * 3 mm (thickness), and the solvent is dried in a drying oven at 60° C. to obtain a negative electrode layer, which is a negative electrode layer that does not contact an electrolyte and can be assembled in a negative electrode mold of a zinc-air battery.

[0063] (2) Provide 60 mg of catalyst, 10 mg of micro-nano conductive carbon material, 20 μL of PVDF slurry and 30 mL of anhydrous ethanol; place the oxygen catalyst and micro-nano conductive carbon material in a mortar, add anhydrous ethanol and PVDF slurry, grind for 30 minutes until it is in a sheet shape, roll it into a thin layer, dry it at 60°C, cut it to obtain a catalytic layer, and assemble it in a positive electrode mold of a zinc-air battery.

[0064] Specifically, nickel foam is used as the current collector, the length and width of the current collector are 4cm*5cm, the length and width of the waterproof and breathable conductive film are 3.5cm*3.5cm, and the length and width of the catalyst layer are 1cm*1cm. The thickness of the current collector is 1mm. The current collector is used to connect the catalyst layer and the external circuit. The thickness of the waterproof and breathable conductive film is 0.7mm. After the positive and negative electrodes are prepared, pour 70mL6molL -1 KOH and 10 μL BS-12 electrolyte form a zinc powder air battery (denoted as E(1)C B (1) / BS-12(10), and discharge begins. Where, E represents E-44 epoxy resin, and the 1 in the bracket corresponding to E represents the mass of E-44 epoxy resin, C B Indicates SuperC45 carbon black mixture, C B The 1 in the brackets indicates that the amount of Super C45 carbon black is 50 mg, BS-12 indicates dodecyl dimethyl betaine, and 10 in (10) indicates the volume of BS-12). The catalyst may be a commercial platinum-carbon catalyst, model: JM20% platinum-carbon.

[0065] Embodiment 2

[0066] The difference from Example 1 is that the amount of E-44 epoxy resin used is 0.5 g, and the zinc powder air battery (denoted as E(0.5)C B (1) / BS-12(10), E corresponds to the 0.5 in the brackets and represents the mass of E-44 epoxy resin), and discharge begins.

[0067] Embodiment 3

[0068] The difference from Example 1 is that the amount of E-44 epoxy resin used is 1.5 g, and the zinc powder air battery (denoted as E(1.5)C B (1) / BS-12(10), E corresponds to the 1.5 in the brackets and represents the mass of E-44 epoxy resin), and discharge begins.

[0069] Embodiment 4

[0070] The difference from Example 1 is that the amount of E-44 epoxy resin used is 2 g, and the zinc powder air battery (denoted as E(2)C B(1) / BS-12(10), E corresponds to the 2 in the brackets and represents the mass of E-44 epoxy resin), and discharge begins.

[0071] Embodiment 6

[0072] (1) Dissolve 1 g of E-44 epoxy resin in 5 g of anhydrous ethanol, add 2 g of 100-mesh zinc powder and 50 mg of Super C45 carbon black mixture, and stir vigorously for 1 h to precipitate to obtain zinc powder slurry; spin-coat the obtained zinc powder slurry onto a porous conductive substrate nickel foam of 70 mm (length) * 30 mm (width) * 3 mm (thickness), dry the solvent in a drying oven at 60° C. to obtain a negative electrode layer, and assemble it into a negative electrode mold of a zinc-air battery.

[0073] (2) Provide 60 mg of catalyst, 10 mg of micro-nano conductive carbon material, 20 μL of PVDF slurry and 30 mL of anhydrous ethanol; place the oxygen catalyst and micro-nano conductive carbon material in a mortar, add anhydrous ethanol and PVDF slurry, grind for 30 minutes until it is in a sheet shape, roll it into a thin layer, dry it at 60°C, cut it to obtain a catalytic layer, and assemble it in a positive electrode mold of a zinc-air battery.

[0074] Specifically, nickel foam is used as the current collector, the length and width of the current collector are 4cm*5cm, the length and width of the waterproof and breathable conductive film are 3.5cm*3.5cm, and the length and width of the catalyst layer are 1cm*1cm. The thickness of the current collector is 1mm. The current collector is used to connect the catalyst layer and the external circuit. The thickness of the waterproof and breathable conductive film is 0.7mm. After the positive and negative electrodes are prepared, pour 70mL6molL -1 KOH and 10 μL BS-12 electrolyte form a zinc powder air battery (denoted as E(1)C B (1) Zn 100 / BS-12(10), and start discharging. Among them, Zn 100 The mesh number of zinc powder is 100). The catalyst may be a commercial platinum-carbon catalyst, model: JM20% platinum-carbon.

[0075] Specifically, different from the first embodiment, the mesh size of the zinc powder used is 100 mesh (150 microns).

[0076] Embodiment 7

[0077] (1) Dissolve 1 g of E-44 epoxy resin in 5 g of anhydrous ethanol, add 2 g of 800-mesh zinc powder and 25 mg of Super C45 carbon black mixture, and stir vigorously for 1 h to precipitate to obtain zinc powder slurry; spin-coat the obtained zinc powder slurry onto a porous conductive substrate nickel foam of 70 mm (length) * 30 mm (width) * 3 mm (thickness), dry the solvent in a drying oven at 60° C. to obtain a negative electrode layer, and assemble it into a negative electrode mold of a zinc-air battery.

[0078] (2) Provide 60 mg of catalyst, 10 mg of micro-nano conductive carbon material, 20 μL of PVDF slurry and 30 mL of anhydrous ethanol; place the oxygen catalyst and micro-nano conductive carbon material in a mortar, add anhydrous ethanol and PVDF slurry, grind for 30 minutes until it is in a sheet shape, roll it into a thin layer, dry it at 60°C, cut it to obtain a catalytic layer, and assemble it in a positive electrode mold of a zinc-air battery.

[0079] Specifically, nickel foam is used as the current collector, the length and width of the current collector are 4cm*5cm, the length and width of the waterproof and breathable conductive film are 3.5cm*3.5cm, and the length and width of the catalyst layer are 1cm*1cm. The thickness of the current collector is 1mm. The current collector is used to connect the catalyst layer and the external circuit. The thickness of the waterproof and breathable conductive film is 0.7mm. After the positive and negative electrodes are prepared, pour 70mL6molL -1 KOH and 10 μL BS-12 electrolyte form a zinc powder air battery (denoted as E(1)C B (0.5) / BS-12(10), and discharge begins. B The 0.5 in the corresponding brackets represents the mass ratio of the Super C45 carbon black in Example 7 to the Super C45 carbon black in Example 1). The catalyst may be a commercial platinum-carbon catalyst, model: JM 20% platinum-carbon.

[0080] Specifically, different from Example 1, the amount of Super C45 carbon black used is 25 mg.

[0081] Embodiment 8

[0082] The difference from Example 1 is that the amount of Super C45 carbon black used is 100 mg, and the zinc powder air battery (denoted as E(1)C B (2) / BS-12(10), start discharging. Among them, C B The 2 in the corresponding brackets represents the mass ratio of the Super C45 carbon black in Example 8 to the Super C45 carbon black in Example 1).

[0083] Embodiment 9

[0084] The difference from Example 1 is that the amount of Super C45 carbon black used is 200 mg, and the zinc powder air battery (denoted as E(1)C B (4) / BS-12(10), start discharging. Among them, C B The 4 in the corresponding brackets represents the mass ratio of the Super C45 carbon black in Example 9 to the Super C45 carbon black in Example 1).

[0085] Embodiment 10

[0086] Different from Example 7, no micro-nano conductive carbon material is used, and zinc powder is directly mixed with E-44 epoxy resin to assemble a zinc powder air battery (denoted as E(1)C B (0) / BS-12(10), start discharging. Among them, C B The 0 in the corresponding brackets means that no Super C45 carbon black is added).

[0087] Embodiment 11

[0088] (1) Dissolve 1 g of E-44 epoxy resin in 5 g of anhydrous ethanol, add 2 g of 800-mesh zinc powder and 50 mg of Super C45 carbon black mixture, and stir vigorously for 1 h to precipitate to obtain zinc powder slurry; spin-coat the obtained zinc powder slurry onto a porous conductive substrate nickel foam of 70 mm (length) * 30 mm (width) * 3 mm (thickness), dry the solvent in a drying oven at 60° C. to obtain a negative electrode layer, and assemble it into a negative electrode mold of a zinc-air battery.

[0089] (2) Provide 60 mg of catalyst, 10 mg of micro-nano conductive carbon material, 20 μL of PVDF slurry and 30 mL of anhydrous ethanol; place the oxygen catalyst and micro-nano conductive carbon material in a mortar, add anhydrous ethanol and PVDF slurry, grind for 30 minutes until it is in a sheet shape, roll it into a thin layer, dry it at 60°C, cut it to obtain a catalytic layer, and assemble it in a positive electrode mold of a zinc-air battery.

[0090] Specifically, nickel foam is used as the current collector, the length and width of the current collector are 4cm*5cm, the length and width of the waterproof and breathable conductive film are 3.5cm*3.5cm, and the length and width of the catalyst layer are 1cm*1cm. The thickness of the current collector is 1mm. The current collector is used to connect the catalyst layer and the external circuit. The thickness of the waterproof and breathable conductive film is 0.7mm. After the positive and negative electrodes are prepared, pour 70mL6molL -1 The electrolyte of KOH forms a zinc powder air battery (denoted as E(1)C B (1)), start discharging. The catalyst can be a commercial platinum-carbon catalyst, model: JM20% platinum-carbon.

[0091] Specifically, different from the first embodiment, the electrolyte directly uses 6M KOH without adding BS-12.

[0092] Embodiment 12

[0093] The difference from Example 1 is that the electrolyte is 6 mol L -1 KOH and 5 μL BS-12 mixture were assembled into a zinc powder air battery (denoted as E(1)C B (1) / BS-12(5), 5 in (5) represents the volume of BS-12), and discharge begins.

[0094] Embodiment 13

[0095] The difference from Example 1 is that the electrolyte is 6 mol L -1 KOH and 25 μL of BS-12 mixture were assembled into a zinc powder air battery (denoted as E(1)C B (1) / BS-12(25), 25 in (25) represents the volume of BS-12), and discharge begins.

[0096] Embodiment 14

[0097] The difference from Example 1 is that the electrolyte is 6 mol L -1 KOH and 50 μL of BS-12 mixture were assembled into a zinc powder air battery (denoted as E(1)C B (1) / BS-12(50), 50 in (50) represents the volume of BS-12), and discharge begins.

[0098] Comparative Example 1

[0099] Different from the first embodiment, 2 g of high-purity zinc sheet (purity 99.999%, thickness 0.3 mm) was placed in a battery mold, assembled into a battery (referred to as zinc sheet), and discharge was started.

[0100] Comparative Example 2

[0101] The difference from Example 1 is that "10 μL of BS-12" is replaced by 4 mg of betaine BS to assemble a zinc powder air battery (denoted as E(1)C B (1) / BS), and start discharging.

[0102] Comparative Example 3

[0103] The difference from Example 1 is that "10 μL of BS-12" is replaced by 20 μL of dodecane DD to assemble a zinc powder air battery (denoted as E(1)C B (1) / DD), start discharging.

[0104] Process route such as Figure 1 As shown, based on the hydrophobicity and adhesion of E-44 epoxy resin, it is mixed with zinc powder and conductive carbon black in a volatile solvent, then spin-coated on a conductive substrate, and dried to form a negative electrode layer, which reduces the corrosion and shedding of zinc powder. During the discharge process, the surfactant BS-12 is added, and its hydrophobic dodecyl long chain and the hydrophobic group (benzene ring) of E-44 epoxy resin have a close relationship, and the two synergistically improve the corrosion inhibition ability of zinc-air batteries. The hydrophilic carboxyl group has a close relationship with zinc, improves the wettability of the electrode, and promotes the ion transfer ability.

[0105] like Figure 2As shown in the figure, since the negative electrode layer just dried has not been immersed in the solution, the surface contact angle of the negative electrode layer is (115.64°~119.11°), which is hydrophobic. After the negative electrode layer is immersed in a 30wt% BS-12 aqueous solution for 12h (denoted as E(1)C B (1) / BS-12), the measurement found E(1)C B The contact angle of (1) / BS-12 decreased to 29.26°, indicating hydrophilicity. This indicates that BS-12 is adsorbed on the electrode surface and improves the wettability of the electrode surface.

[0106] like Figure 3 As shown, the negative electrode layer was immersed in 6M KOH and 10μL BS-12 for 6h (denoted as E(1)C B (1) / BS-12-KOH). In addition, the other negative electrode layer was immersed in 6M KOH solution for 6 h (denoted as E(1)C B (1) / KOH). The negative electrode layer just dried was not immersed in the solution. Infrared spectroscopy confirmed that the surface of the negative electrode layer had a characteristic vibration absorption peak of E-44 epoxy resin, 2872 cm -1 The symmetric / asymmetric contraction vibrations of methylene groups are located at 1607, 1581, 1507, and 830 cm -1 The peaks at 914 cm-1 belong to the stretching vibrations of the C=C bond and the =CH bond on the benzene ring. -1 The peak at is the characteristic absorption of the epoxy group, which confirms the formation of the hydrophobic interface of the hydrophobic E-44 epoxy resin. After soaking in KOH solution, E(1)C B (1) / KOH, E(1)C B The fundamental vibration peak of E-44 epoxy resin in (1) / KOH did not disappear or shift, which confirmed that E-44 epoxy resin can still maintain good protective bonding effect under harsh alkaline conditions for a long time. In addition, after soaking in 6M KOH and 10μL BS-12, E(1)C B (1) / BS-12-KOH, the fundamental vibration absorption peak of E-44 epoxy resin can still be clearly found, and at 1296 cm -1 The absorption peak of quaternary ammonium salt was observed nearby, confirming that BS-12 was adsorbed on the surface of the negative electrode layer.

[0107] like Figure 4 As shown, based on the negative electrode layer formed by E-44 epoxy resin, the effects of different additives on the discharge performance of zinc-air batteries are compared, specifically involving the zinc powder air battery E(1)C of Example 1 B (1) / BS-12(10), zinc powder air battery E(1)C of Example 11 B(1), zinc sheet-based air battery of comparative example 1, zinc powder-based air battery of comparative example 2 E(1)C B (1) / BS, zinc powder air battery E(1)C of comparative example 3 B (1) / DD.

[0108] At 100mA cm -2 The discharge voltage of the zinc sheet in Comparative Example 1 is 0.77V, and the specific capacity calculated by the formula is 710mAhg -1 At 100mA cm -2 Next, E(1)C B (1) / BS-12(10) The discharge voltage is 0.78 V. 2 g of zinc powder can be discharged for 11 h. The specific capacity is calculated to be 550 mAh g -1 , reaching 77% of the specific capacity of zinc sheets. Dodecane DD was used as an additive and assembled into a zinc powder air battery E(1)C B (1) / DD. Due to the poor wettability of the interface and the obstruction of zinc ion transfer, the polarization and internal resistance of the battery reaction are increased. From the voltage polarization between 0 and 2h, it can be seen that the interface infiltration requires a certain amount of time. At 100mAcm -2 Next, E(1)C B (1) / DD discharge voltage is lower than E(1)C B (1) / BS-12(10) and is stable at about 0.72V. 2g of zinc powder can be discharged for 10h, and the specific capacity is calculated to be 500mAhg -1 , only 70% of the specific capacity of the zinc sheet. B (1) The lack of hydrophobic groups in betaine BS in BS results in low corrosion and utilization of zinc powder. -2 Next E(1)C B (1) The discharge voltage of / BS is relatively low, only 0.63 V. 2 g of zinc powder can be discharged for 10 h, and the specific capacity is calculated to be 500 mAh g -1 , only 70% of the specific capacity of zinc sheet. E(1)C B (1) It also lacks the hydrophobic groups of BS-12, so there is also the effect of self-corrosion on the discharge voltage and specific capacity. In addition, due to the inherent hydrophobicity of E-44 epoxy resin, its interface wetting in the electrolyte is poor. At 100mAcm -2 Next, E(1)C B The discharge voltage of (1) is even lower than that of E(1)C B (1) / BS (0.58V Vs 0.63V), 2g zinc powder can be discharged for 10.4h, and the specific capacity is calculated to be 520mAhg -1In summary, adding BS-12 and E-44 epoxy resins having both hydrophilic and hydrophobic groups to form a mixed corrosion inhibitor can achieve better corrosion inhibition effect and interface wetting effect.

[0109] Figure 5 The effects of different concentrations of BS-12 on battery discharge are given, specifically relating to the zinc powder air battery E(1)C of Example 1 B (1) / BS-12(10), zinc powder air battery E(1)C of Example 11 B (1) Zinc powder air battery E(1)C of Example 12 B (1) / BS-12(5), zinc powder air battery E(1)C of Example 13 B (1) / BS-12(25), zinc powder air battery E(1)C of Example 14 B (1) / BS-12(50). At 100mA cm -2 Next, due to E(1)C B (1) The poor wettability of the interface results in an average discharge voltage of 0.58 V, a discharge time of 10.4 h, and a calculated specific capacity of 520 mAh g -1 . E(1)C B The BS-12 adsorbed on the surface of (1) / BS-12(5) did not reach saturation, the average discharge voltage was 0.65 V, the discharge time was 10 h, and the calculated specific capacity was 500 mAh g -1 . E(1)C B (1) / BS-12(10) has the best BS-12 adsorption amount, that is, BS-12 reaches the best adsorption amount on the surface of the negative electrode layer. The average discharge voltage is 0.78V, the discharge time is 11h, and the calculated specific capacity is 550mAhg -1 Then increasing the concentration of BS-12 may hinder the ion transfer. Therefore, E(1)C B (1) / BS-12(25), E(1)C B (1) / BS-12(50) has a similar discharge voltage of 0.72 V, a discharge time of 9.8 h, and a specific capacity of 490 mAh / g. Both performances are inferior to E(1)C B (1) / BS-12(10).

[0110] Figure 6 The effects of different amounts of E-44 epoxy resin added on battery discharge are given. B (1) / BS-12(10), zinc powder air battery E(0.5)C of Example 2 B (1) / BS-12(10), zinc powder air battery E(1.5)C of Example 3B (1) / BS-12(10), zinc powder air battery E of Example 4(2)C B (1) / BS-12(10). Due to the poor conductivity of E-44 epoxy resin, it is necessary to explore the balance between its conductivity and hydrophobicity. Low content of E-44 epoxy resin may lead to poor hydrophobicity, resulting in zinc powder corrosion and low specific capacity. High content of E-44 epoxy resin may lead to greater internal resistance and polarization of the battery. Therefore, when the content of E-44 epoxy resin is 1g, E(1)C B (1) / BS-12(10) has the best discharge performance. At 20mA cm -2 Under this condition, the discharge voltage is 1.33V and the discharge time is 43h. E(0.5)C B (1) / BS-12(10), E(1.5)C B (1) / BS-12(10), E(2)C B The discharge voltages of (1) / BS-12(10) are 1.13 V, 1.06 V, and 0.8 V, respectively, and the discharge times are 41.5 h, 37.3 h, and 36 h, respectively.

[0111] Figure 7 The results of the zinc powder-air battery with different contents of conductive carbon black at 100 mA cm -2 The constant current discharge curve is shown below. Carbon black is a conductive agent combined with zinc powder. The amount of carbon black added also has a great influence on the discharge performance. Excessive carbon black reduces the relative content of zinc powder, the active substance of the battery, resulting in poor battery discharge capacity. However, less carbon black cannot balance the disadvantage of increased battery internal resistance due to the non-conductivity of E-44 epoxy resin. Specifically related to the zinc powder air battery E(1)C of Example 1 B (1) / BS-12(10), zinc powder air battery E(1)C of Example 7 B (0.5) / BS-12(10), zinc powder air battery E(1)C of Example 8 B (2) / BS-12(10), zinc powder air battery E(1)C of Example 9 B (4) / BS-12(10), zinc powder air battery E(1)C of Example 10 B (0) / BS-12(10). Wherein, E(1) represents 1g of E-44 epoxy resin, C B (0), C B (0.5), C B (1) C B (2) C B (4) represents 0 mg, 25 mg, 50 mg, 100 mg, and 200 mg of conductive carbon black, respectively.-2 Next, E(1)C B The average discharge voltage of (1) / BS-12(10) is 0.78 V, the discharge time is 11 h, and the calculated specific capacity is 550 mAh g -1 , reaching 77% of the specific capacity of the zinc sheet. In contrast, E(1)C B (0) / BS-12(10), E(1)C B (0.5) / BS-12(10), E(1)C B (2) / BS-12(10), E(1)C B The discharge voltages of (2) / BS-12(10) were 0.66, 0.68, 0.66, and 0.64 V, respectively, and the discharge times were 9.0, 10.8, 11.1, and 9.8 h, respectively. The calculated specific capacities were 450, 540, 555, and 490 mAh g -1 .

[0112] Since the zinc powder particles are fine and have a large specific surface area, they can fully contact with the electrolyte, which leads to serious self-corrosion of the zinc powder. The present invention effectively prevents the zinc powder from directly contacting the electrolyte through the hydrophobic effect of the E-44 epoxy resin. Figure 8 As shown, E(1)C B The Tafel corrosion curve potential of (1) is positively shifted compared with the zinc sheet, and the corrosion current is reduced (the ordinate is more negative). However, due to the poor wettability of the E-44 epoxy resin (the contact angle is 115.64°~119.11°), the OH - Insufficient concentration further leads to the formation of zinc oxide and a decrease in conductivity, resulting in a passivation effect.

[0113]

[0114]

[0115] like Fig. 9 As shown, in E(1)C B (1) The adsorbed BS-12 changes the wetting effect between the electrode and the electrolyte (the contact angle is 29.26°), thus effectively preventing the local OH - The passivation effect caused by insufficient E(1)C B The appropriate amount of BS-12 in (1) / BS-12(10) destroyed the formation of the passivation layer and optimized the corrosion current and corrosion potential. After optimization, the corrosion potential shifted from the original -1.521V to -1.545V, and the corrosion current on the ordinate increased (the ordinate was more positive).

[0116] like Fig.10 As shown, with E(1)C B(1) Compared with E(1)C B The adsorbed BS-12 molecules in (1) / BS-12(10) cause the corrosion potential to shift negatively and increase the corrosion current, but this does not mean that the corrosion effect is increased again, but only prevents the formation of the passivation layer. The combined corrosion inhibition of the two can effectively prevent OH - The corrosion of zinc powder and the occurrence of hydrogen evolution reaction. It can be seen from the figure that the hydrogen evolution current is significantly reduced.

[0117] Fig.11 is E(1)C B (1) / BS-12 (10) and zinc sheet assembled zinc air battery power density curve. Specifically related to Example 1 zinc powder air battery E (1) C B (1) / BS-12(10) and the zinc sheet-based air battery of comparative example 1. At 160 mA cm -2 Next, calculate E(1)C B (1) / BS-12(10) has a peak power density of 67 mW cm -2 , and zinc sheet (68mW cm -2 ) has a peak power density close to that of the

[0118] Fig.12 The effects of zinc powders with different mesh sizes on battery discharge performance were compared. Theoretically, the larger the mesh size of zinc powder, the smaller its particle size and the higher its reaction activity, accompanied by severe corrosion. Therefore, the discharge voltage of 800-mesh zinc powder will be greater than that of 100-mesh zinc powder, while the specific capacity will be lower than that of 100-mesh zinc powder. The experimental results show that E(1)C B (1) Zn 100 The discharge voltage of / BS-12(10) is 0.68V, the discharge time is 11.8h, and the specific capacity is 590mAhg -1 , reaching 83% of the specific capacity of the zinc sheet. B The discharge voltage of (1) / BS-12(10) is 0.78 V, the discharge time is 11 h, and the specific capacity is 550 mAh g -1 , reaching 77% of the specific capacity of the zinc sheet, which is consistent with the theory.

[0119] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a zinc powder air battery containing a mixed corrosion inhibitor, characterized in that: The following steps are involved: Dissolving E-44 epoxy resin in a volatile solvent, adding a mixture of zinc powder and micro-nano conductive carbon material, and stirring to obtain a zinc powder slurry; Spin coating the zinc powder slurry onto a porous conductive substrate, and drying to obtain a negative electrode layer; A zinc powder air battery is assembled based on an air positive electrode, the negative electrode layer and an alkaline electrolyte; wherein the alkaline electrolyte comprises: a strong base, dodecyl dimethyl betaine and water; the ratio of the E-44 epoxy resin, the zinc powder, the micro-nano conductive carbon material and the dodecyl dimethyl betaine is: 0.5-2g: 2g: 25-200mg: 5-50μL.

2. The method for preparing a zinc powder-air battery containing a mixed corrosion inhibitor according to claim 1, characterized in that: The ratio of the E-44 epoxy resin, the zinc powder, the micro-nano conductive carbon material, and the dodecyl dimethyl betaine is: 0.5-2 g: 2 g: 50 mg: 10-50 μL.

3. The method for preparing a zinc powder-air battery containing a mixed corrosion inhibitor according to claim 2, characterized in that: The ratio of the E-44 epoxy resin, the zinc powder, the micro-nano conductive carbon material, and the dodecyl dimethyl betaine is: 1 g: 2 g: 50 mg: 10 μL.

4. The method for preparing a zinc powder-air battery containing a mixed corrosion inhibitor according to claim 1, characterized in that: The micro-nano conductive carbon material is conductive carbon black; and the volatile solvent is anhydrous ethanol.

5. The method for preparing a zinc powder-air battery containing a mixed corrosion inhibitor according to claim 1, characterized in that: The mesh size of the zinc powder is 100 to 800 meshes.

6. The method for preparing a zinc powder-air battery containing a mixed corrosion inhibitor according to claim 1, characterized in that: The stirring time is 0.5 to 3 hours.

7. The method for preparing a zinc powder-air battery containing a mixed corrosion inhibitor according to claim 1, characterized in that: The porous conductive substrate is nickel foam.

8. The method for preparing a zinc powder-air battery containing a mixed corrosion inhibitor according to claim 1, characterized in that: The strong base is KOH; The concentration of the strong base is 6 mol L -1 .

9. The method for preparing a zinc powder-air battery containing a mixed corrosion inhibitor according to claim 1, characterized in that: The air positive electrode is obtained by the following steps: The catalyst, micro-nano conductive carbon material, polytetrafluoroethylene and volatile solvent are mixed and rolled into a catalyst layer; wherein the catalyst is Pt / C and the loading amount is 1-5 mg cm -2 ; The waterproof and breathable conductive membrane and the catalyst layer are stacked on the current collector in sequence to obtain an air positive electrode.

10. A zinc powder air battery containing a mixed corrosion inhibitor, characterized in that: The method is adopted as claimed in any one of claims 1 to 9.

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