A neutral electrolyte aluminum-air battery and its preparation method

Abstract

The present invention discloses a neutral aluminum-air battery and a preparation method thereof, aiming to solve the problems of low utilization rate of aluminum hydroxide adsorbed on the negative electrode and positive shift of the negative electrode potential in the existing neutral electrolyte aluminum-air battery. The technical solution sequentially includes the following steps: Weigh activated carbon, carbon black, binder, zinc oxide, dispersant, and solvent according to the mass ratio of 0.8-1.2∶0.8-1.2∶0.8-1.2∶0.4-0.6∶0.4-0.6∶4.8-7.2, and mix and stir for 2-4 h to prepare a slurry; Coat the slurry prepared in step 1) on both sides of an aluminum sheet; Dry the aluminum sheet coated in step 2) to completely volatilize the solvent, so that a porous structure is formed on the coating layer; Prepare a sodium chloride solution and add 0.4-06% sodium carboxymethyl cellulose as an additive; Assemble it with an air electrode to form an aluminum-air battery; It belongs to the field of air batteries.

Description

Technical Field

[0001] The present invention discloses an air battery, specifically, a neutral electrolyte aluminum-air battery, belonging to the field of air batteries. Background Art

[0002] Aluminum is the most abundant metallic element in the earth's crust, with low price, environmental protection, safety, high specific energy, and long storage life, making it an ideal negative electrode material. Aluminum-air battery is a kind of metal-air battery that has been widely studied at present. Due to its low manufacturing cost, environmental protection, non-toxicity, high energy density, and convenient and safe storage and transportation, aluminum-air battery has become an ideal energy storage device and power source.

[0003] In the existing technology, the aluminum-air battery uses aluminum or aluminum alloy as the negative electrode and oxygen in the air as the positive electrode. Under the combined action of the electrolyte and the catalyst, an electrochemical reaction occurs to form an electric current for power generation. When the aluminum-air battery is applied to fields such as electric vehicles and underwater vehicles that require long-term power supply, it has obvious cost and endurance advantages compared with lead-acid batteries and lithium batteries. When the aluminum-air battery is applied to small-power power supply fields such as portable power sources and electronic devices, it has higher safety and sustainability advantages compared with lithium batteries.

[0004] However, there are still some technical bottlenecks in the research and development of neutral aluminum-air batteries. On the one hand, in the neutral electrolyte, due to the intermolecular action of aluminum-aluminum oxide-aluminum hydroxide, the aluminum hydroxide product covers the negative electrode plate. Since the structure of aluminum hydroxide is dense, it is difficult for the aluminum sheet to further discharge, resulting in low utilization rate of the negative electrode and the positive shift of the negative electrode potential, which causes the voltage of the entire battery to decrease. Summary of the Invention

[0005] Aiming at the above-mentioned disadvantages and deficiencies of the existing technology, the purpose of the present invention is to provide a neutral aluminum-air battery to solve the problems such as low utilization rate of the negative electrode adsorbed by aluminum hydroxide and positive shift of the negative electrode potential in the existing neutral electrolyte aluminum-air battery.

[0006] Therefore, the first technical solution provided by the present invention is as follows:

[0007] A preparation method of a neutral electrolyte aluminum-air battery, successively including the following steps:

[0008] 1) Weigh activated carbon, carbon black, binder, zinc oxide, dispersant, and solvent according to the mass ratio of 0.8-1.2∶0.8-1.2∶0.8-1.2∶0.4-0.6∶0.4-0.6∶4.8-7.2, and mix and stir for 2-4 h to make a slurry;

[0009] 2) Coat the slurry prepared in step 1) on both sides of the aluminum sheet;

[0010] 3) Dry the aluminum sheet after coating in step 2), evaporate the solvent completely, and form a porous structure on the coating layer;

[0011] 4) Prepare a sodium chloride solution and add 0.4 - 0.6% sodium carboxymethylcellulose as an additive;

[0012] 5) Assemble it with an air electrode to form an aluminum - air battery.

[0013] As a further preference of the present invention, in the preparation method of the neutral electrolyte aluminum - air battery described above, the binder is a PVDF lithium - battery binder.

[0014] As a further preference of the present invention, in the preparation method of the neutral electrolyte aluminum - air battery described above, the dispersant is a CNT dispersant.

[0015] As a further preference of the present invention, in the preparation method of the neutral electrolyte aluminum - air battery described above, the solvent is N - methyl - 2 - pyrrolidone.

[0016] As a further preference of the present invention, in the preparation method of the neutral electrolyte aluminum - air battery described above, the concentration of the sodium chloride solution is 2M.

[0017] As a further preference of the present invention, in the preparation method of the neutral electrolyte aluminum - air battery described above, the coating thickness of the slurry is 200 microns.

[0018] As a further preference of the present invention, in the preparation method of the neutral electrolyte aluminum - air battery described above, the thickness of the aluminum sheet is 3mm.

[0019] The second technical solution provided by the present invention is a neutral electrolyte aluminum - air battery prepared by the above - mentioned method.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. The technical solution provided by the present invention forms a slurry through carbon materials, additives, dispersants, binders, NMP, etc., which is coated on the surface of the aluminum sheet. By drying, NMP is evaporated, and a porous carbon layer is prepared, making it difficult for aluminum hydroxide to adsorb on the aluminum sheet. At the same time, due to the porous structure of the carbon layer, the discharge process of the aluminum sheet is not affected, thereby improving the utilization rate of the aluminum sheet and reducing the negative electrode potential of the aluminum sheet.

[0022] 2. Since sodium carboxymethylcellulose is added as an additive in the electrolyte in the technical solution provided by the present invention, the carboxyl groups of sodium carboxymethylcellulose will strongly bind on the surface of the negative electrode, and at the same time combine with zinc in the carbon layer to form a complex and stable thin layer, thereby preventing aluminum hydroxide from adsorbing on the surface and achieving an anti - corrosion effect.

[0023] 3. Due to the combined use and mutual influence of the negative carbon layer and the electrolyte additive in the technical solution provided by the present invention, a synergistic effect is produced, resulting in good anti-corrosion and anti-adsorption effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a structural diagram of an air electrode assembled into an aluminum-air battery provided by this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present invention will be further described in detail below in conjunction with embodiments, but the embodiments of the present invention are not limited thereto.

[0026] Embodiment 1

[0027] A neutral electrolyte aluminum-air battery provided in this embodiment is prepared by the following method:

[0028] The first step: Prepare the slurry

[0029] Weigh activated carbon, carbon black, PVDF binder, zinc oxide, CNT dispersant, and NMP solvent according to a mass ratio of 1:1:1:0.5:0.5:6, and stir for 3 hours to make a slurry;

[0030] The second step

[0031] Apply the slurry prepared in the first step to both sides of an aluminum sheet with a thickness of 3 mm (the size of the aluminum sheet is: 18*20*2 mm), and the coating thickness is: 200 microns;

[0032] The third step

[0033] Dry at 100 °C for 3 hours to volatilize all the NMP solvent, so that the coating layer forms a porous structure;

[0034] The fourth step: Prepare the neutral electrolyte

[0035] Prepare a 2M sodium chloride solution, and add sodium carboxymethylcellulose with a mass fraction of 0.5% as an additive to the sodium chloride solution.

[0036] The fifth step: The effective area of the air electrode is 25*25 mm, and it is assembled with the air electrode into an aluminum-air battery, refer to Figure 1 .

[0037] Embodiment 2

[0038] A neutral electrolyte aluminum-air battery provided in this embodiment is prepared by the following method:

[0039] The first step: Prepare the slurry

[0040] Weigh activated carbon, carbon black, PVDF binder, zinc oxide, CNT dispersant, and NMP solvent according to the mass ratio of 1.2:0.8:1.2:0.4:0.6:4.8, and stir for 3 h to make a slurry;

[0041] The second step

[0042] Apply the slurry prepared in the first step to both sides of an aluminum sheet with a thickness of 3 mm (the size of the aluminum sheet is: 18*20*2 mm), and the coating thickness is: 200 microns;

[0043] The third step

[0044] Dry at 100 °C for 3 h to volatilize the NMP solvent completely, and make the coating layer form a porous structure;

[0045] The fourth step: Preparation of neutral electrolyte

[0046] Prepare a 2M sodium chloride solution, and add sodium carboxymethylcellulose with a mass fraction of 0.5% as an additive to the sodium chloride solution.

[0047] The fifth step: The air electrode has an effective area of 25*25 mm, and is assembled with the air electrode into an aluminum-air battery, refer to Figure 1 .

[0048] Example 3

[0049] A neutral electrolyte aluminum-air battery provided in this example is prepared by the following method:

[0050] The first step: Preparation of slurry

[0051] Weigh activated carbon, carbon black, PVDF binder, zinc oxide, CNT dispersant, and NMP solvent according to the mass ratio of 0.8:1.2:0.8:0.6:0.4:7.2, and stir for 3 h to make a slurry;

[0052] The second step

[0053] Apply the slurry prepared in the first step to both sides of an aluminum sheet with a thickness of 3 mm (the size of the aluminum sheet is: 18*20*2 mm), and the coating thickness is: 200 microns;

[0054] The third step

[0055] Dry at 100 °C for 3 h to volatilize the NMP solvent completely, and make the coating layer form a porous structure;

[0056] The fourth step: Preparation of neutral electrolyte

[0057] Prepare a 2M sodium chloride solution, and add sodium carboxymethylcellulose with a mass fraction of 0.5% as an additive to the sodium chloride solution.

[0058] Step 5: The air electrode has an effective area of 25 * 25 mm and is assembled with the air electrode into an aluminum-air battery. Refer to Figure 1 。

[0059] Example 4

[0060] A neutral electrolyte aluminum-air battery provided in this example is prepared by the following method:

[0061] Step 1: Prepare the slurry

[0062] Weigh activated carbon, carbon black, PVDF binder, zinc oxide, CNT dispersant, and NMP solvent according to the mass ratio of 0.8:1:0.8:0.5:0.5:6, and stir for 3 h to make the slurry;

[0063] Step 2

[0064] Apply the slurry prepared in the first step to both sides of an aluminum sheet with a thickness of 3 mm (the size of the aluminum sheet is: 18 * 20 * 2 mm), and the coating thickness is: 200 microns;

[0065] Step 3

[0066] Dry at 100 °C for 3 h to completely volatilize the NMP solvent and form a porous structure on the coating layer;

[0067] Step 4: Prepare the neutral electrolyte

[0068] Prepare a 2M sodium chloride solution, and add sodium carboxymethyl cellulose with a mass fraction of 0.5% as an additive to the sodium chloride solution.

[0069] Step 5: The air electrode has an effective area of 25 * 25 mm and is assembled with the air electrode into an aluminum-air battery. Refer to Figure 1 。

[0070] Comparative Example 1

[0071] The difference between this comparative example and Example 1 is that carbon black is missing in the first step.

[0072] Comparative Example 2

[0073] The difference between this comparative example and Example 1 is that zinc oxide is missing in the first step.

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 1 is that CNT dispersant is missing in the first step.

[0076] Comparative Example 4

[0077] The difference between this comparative example and Example 1 is that sodium carboxymethyl cellulose is missing in the fourth step.

[0078] To better prove the technical solution provided by this application, the experimental test methods and results of the technical solution provided by this application are now given.

[0079] 1. Test method: The electrochemical performance is tested by a battery tester (the cut-off voltage is 0.0V, and the discharge current density is 5 mA / cm 2 )

[0080] 2. The test results are shown in Table 1.

[0081] Table 1

[0082]

[0083] From the above table, it can be seen that the technical solution provided by this application has a good discharge potential and a high capacity density, thus indirectly proving that it also has good anti-corrosion and anti-adsorption effects.

[0084] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method of a neutral electrolyte aluminum-air battery, characterized in that It successively includes the following steps: 1) Weigh activated carbon, carbon black, binder, zinc oxide, dispersant, and solvent according to the mass ratio of 0.8 - 1.2∶0.8 - 1.2∶0.8 - 1.2∶0.4 - 0.6∶0.4 - 0.6∶4.8 - 7.2, and mix and stir for 2 - 4 h to make a slurry; 2) Coat the slurry prepared in step 1) on both sides of the aluminum sheet; 3) Dry the aluminum sheet coated in step 2) until the solvent completely evaporates, so that the coating layer forms a porous structure; 4) Prepare a sodium chloride solution and add 0.4 - 0.6% sodium carboxymethylcellulose by mass fraction as an additive; 5) Assemble it with an air electrode to form an aluminum - air battery; The dispersant is a CNT dispersant; The solvent is N - methyl - 2 - pyrrolidone.

2. The preparation method of the neutral electrolyte aluminum-air battery according to claim 1, characterized in that, The binder is a PVDF lithium - battery binder.

3. The preparation method of the neutral electrolyte aluminum-air battery according to claim 1, wherein, The concentration of the sodium chloride solution is 2 M.

4. The preparation method of the neutral electrolyte aluminum-air battery according to claim 1, characterized in that, The coating thickness of the slurry is 200 microns.

5. The preparation method of the neutral electrolyte aluminum-air battery according to claim 1, characterized in that, The thickness of the aluminum sheet is 3 mm.

6. A neutral - electrolyte aluminum - air battery prepared by the method according to any one of claims 1 - 5.

Images