Alkaline zinc battery positive electrode material and preparation method thereof

Abstract

The invention provides a preparation method of an alkaline zinc battery positive electrode material, which comprises the following steps: immersing foamed nickel into a multi-metal phosphate solution, carrying out first electrodeposition reaction, and then cleaning; anions in the multi-metal phosphate solution comprise phosphate radicals, hydrogen phosphate radicals, dihydrogen phosphate radicals or metaphosphate radicals; the positive ions in the multi-metal phosphate solution comprise nickel, cobalt, iron or copper and inevitably contain nickel; and immersing the foamed nickel into the transition metal compound solution, and carrying out second electrodeposition reaction. According to the preparation method of the alkaline zinc battery positive electrode material, the charge-discharge performance of the alkaline zinc battery positive electrode material is improved, the electric capacity of the alkaline zinc battery positive electrode material is improved, the alkaline zinc battery positive electrode material shows better energy storage performance, meanwhile, the preparation process is simple, the materials are cheap and easy to obtain, the cost is low, consumed time is short, and the method is suitable for industrial production. And the method is energy-saving, low in consumption, green and pollution-free.

Description

Technical Field

[0001] The present invention relates to the field of battery materials, and in particular to an alkaline zinc battery positive electrode material and a preparation method thereof. Background Art

[0002] Electrode materials are an important component of alkaline zinc batteries, among which transition metal compounds are representative electrode materials with high specific capacitance, rich oxidation states, low production costs, eco-friendliness, and clear reversible redox reactions on the electrode surface. Transition metal phosphates have unique physical and chemical structures, adjustable multifunctionality, and open layered skeleton structures, and are therefore favored by researchers. The phosphate group has a special structure and strong coordination ability, and can form soluble complexes with many metal ions, which is conducive to stabilizing the intermediate state of transition metals.

[0003] 202311844739.6 The invention patent of a method for preparing a crystalline / amorphous cobalt pyrophosphate positive electrode material for aqueous zinc-based alkaline batteries discloses a crystalline / amorphous positive electrode material for aqueous zinc-based alkaline batteries, and the positive electrode material is composed of crystalline cobalt pyrophosphate and amorphous cobalt pyrophosphate. First, cobalt phosphate containing crystalline water is prepared in situ on a conductive substrate as a precursor, and then a crystalline / amorphous cobalt pyrophosphate electrode is obtained by CVD pyrolysis, and applied to aqueous zinc-based alkaline batteries, but the energy density of the battery material needs to be improved. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an alkaline zinc battery positive electrode material and a preparation method thereof.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a positive electrode material for an alkaline zinc battery, the preparation method comprising the following steps:

[0006] (1) immersing the nickel foam in a polymetallic phosphate solution, performing a first electrodeposition reaction and then washing; the anions in the polymetallic phosphate solution include phosphate, hydrogen phosphate, dihydrogen phosphate or metaphosphate; the cations in the polymetallic phosphate solution include nickel, cobalt, iron or copper and necessarily contain nickel;

[0007] (2) immersing the nickel foam in a transition metal compound solution, performing a second electrodeposition reaction, and washing and drying to obtain an alkaline zinc battery positive electrode material; the transition metal compound solution is a strong electrolyte, and the cations in the transition metal compound solution are the same as those in step (1);

[0008] The time ratio of the first electrodeposition reaction to the second electrodeposition reaction is 2:(0.5-4).

[0009] The preparation method of the above-mentioned alkaline zinc battery positive electrode material uses nickel foam as a substrate, and sequentially loads polymetallic phosphate and transition metal hydroxide by electrodeposition, and the ratio of polymetallic phosphate and transition metal hydroxide is controlled by the electrodeposition method; the selection of metal elements in the polymetallic phosphate and the regulation of the ratio provide more active sites, and the polymetallic phosphate serves as an intermediate layer between the transition metal hydroxide and the nickel foam, which synergistically improves the charge and discharge performance of the alkaline zinc battery positive electrode material, improves the capacity of the alkaline zinc battery positive electrode material, and makes it exhibit better energy storage performance as an alkaline zinc battery positive electrode material. At the same time, the preparation process of the present invention is simple, the material is cheap and easy to obtain, the cost is low, the time consumption is short, it is convenient for mass production, energy-saving and low-consumption, and it is green and pollution-free.

[0010] Preferably, the cations in the multimetal phosphate solution are nickel, cobalt and copper.

[0011] Preferably, the cations in the multimetal phosphate solution are nickel and cobalt.

[0012] The research on the preparation method of the above-mentioned alkaline zinc battery positive electrode material found that when the cations in the multi-metal phosphate solution are nickel, cobalt and iron, and the cations in the transition metal compound solution are the same as the cations in the multi-metal phosphate solution, the alkaline zinc battery positive electrode material has better capacity and energy density.

[0013] Preferably, the molar ratio of anions to nickel ions in the multi-metal phosphate solution is (1.8-2.2):1.

[0014] Preferably, the electrodeposition reaction is a constant potential deposition method, the deposition potential of the constant potential deposition method is -0.6V to -1.5V, the time of the first electrodeposition reaction is 2 to 8 minutes, and the time of the second electrodeposition reaction is 2 to 8 minutes.

[0015] Preferably, the first electrodeposition reaction time is 2 to 5 minutes, and the second electrodeposition reaction time is 4 to 8 minutes.

[0016] Preferably, the constant potential deposition method is carried out using a three-electrode system, which includes a working electrode, a counter electrode, and a reference electrode. The working electrode is nickel foam or nickel foam loaded with a multi-metal phosphate material, the counter electrode is a platinum sheet, and the reference electrode is a silver chloride-silver chloride saturated potassium chloride electrode.

[0017] Preferably, the concentration of nickel ions in the multi-metal phosphate solution is 0.05 mol / L to 0.5 mol / L, and the concentration of nickel ions in the transition metal compound solution is 0.05 mol / L to 0.5 mol / L.

[0018] Preferably, the methods for cleaning the nickel foam before step (1), cleaning after the first electrodeposition reaction, and cleaning after the second electrodeposition reaction are deionized water, anhydrous ethanol, deionized water, 0.8-1.5 mol / L hydrochloric acid, and deionized water ultrasonic cleaning, respectively.

[0019] Preferably, the cationic compound of the polymetallic phosphate solution is at least two of nickel acetate, cobalt acetate, ferric acetate, nickel nitrate, cobalt nitrate, ferric nitrate, copper nitrate, manganese nitrate, nickel chloride, cobalt chloride, ferric chloride, copper chloride, and manganese chloride; the anionic compound of the polymetallic phosphate solution is potassium dihydrogen phosphate, ammonium phosphate, tricalcium phosphate, sodium hypophosphite, or sodium metaphosphate.

[0020] Preferably, the transition metal compound solution is at least two of nickel acetate, cobalt acetate, iron acetate, nickel nitrate, cobalt nitrate, iron nitrate, copper nitrate, manganese nitrate, nickel chloride, cobalt chloride, iron chloride, copper chloride, and manganese chloride.

[0021] The present invention also provides an alkaline zinc battery positive electrode material prepared by any of the above-mentioned methods for preparing the alkaline zinc battery positive electrode material.

[0022] The present invention also provides an alkaline zinc battery, which comprises the alkaline zinc battery positive electrode material described above.

[0023] The beneficial effects of the present invention are as follows: the present invention provides an alkaline zinc battery positive electrode material and a preparation method thereof. The preparation method of the alkaline zinc battery positive electrode material of the present invention uses nickel foam as a substrate, sequentially loads polymetallic phosphate and transition metal hydroxide by an electrodeposition method, and the ratio of the polymetallic phosphate and the transition metal hydroxide is controlled by the electrodeposition method; the selection of metal elements in the polymetallic phosphate and the regulation of the ratio provide more active sites, and the polymetallic phosphate serves as an intermediate layer between the transition metal hydroxide and the nickel foam, synergistically improving the charge and discharge performance of the alkaline zinc battery positive electrode material, improving the capacity of the alkaline zinc battery positive electrode material, so that the alkaline zinc battery positive electrode material exhibits better energy storage performance, and at the same time, the preparation process of the present invention is simple, the material is cheap and easy to obtain, the cost is low, the time consumption is short, it is convenient for mass production, energy-saving and low-consumption, and it is green and pollution-free. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The cyclic voltammetry curves of the alkaline zinc battery positive electrode material samples of Example 3 of the present invention and Comparative Example 2 are shown, with a scan rate of 5 mV / s.

[0025] Figure 2 The constant current charge and discharge curves of the alkaline zinc battery positive electrode material samples of Example 3 of the present invention and Comparative Example 2 at a current density of 2 A / g.

[0026] Figure 3The cyclic voltammetry curves of the alkaline zinc battery positive electrode material samples of Examples 1 and 3 of the present invention are shown, with a scan rate of 5 mV / s.

[0027] Figure 4 The constant current charge and discharge curves of the alkaline zinc battery positive electrode material samples of Example 1 and Example 3 of the present invention at a current density of 10 A / g. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0029] Example 1

[0030] As a preparation method of an alkaline zinc battery positive electrode material according to an embodiment of the present invention, the preparation method comprises the following steps:

[0031] (1) 1×2cm 2 The nickel foam is treated with distilled water, anhydrous ethanol, distilled water, 1 mol / L hydrochloric acid, and distilled water; after ultrasonic cleaning of the surface, the nickel foam is immersed in a polymetallic phosphate solution for the first electrodeposition reaction and then cleaning; the anions in the polymetallic phosphate solution are dihydrogen phosphate ions; the cations in the polymetallic phosphate solution include nickel and cobalt; the concentration of nickel ions is 0.1 mol / L; the polymetallic phosphate solution is prepared by dissolving nickel nitrate hexahydrate and cobalt nitrate hexahydrate in 50 mL of distilled water in a mass ratio of 1:0.5, and adding sodium dihydrogen phosphate monohydrate to dissolve, and the molar ratio of dihydrogen phosphate ions to nickel ions is 2:1; the electrodeposition reaction is Constant potential deposition method, the constant potential deposition method is carried out using a three-electrode system, the three-electrode system includes a working electrode, a counter electrode, and a reference electrode, the working electrode is nickel foam or nickel foam loaded with multi-metal phosphate materials, the counter electrode is a platinum sheet, and the reference electrode is a silver chloride-silver chloride saturated potassium chloride electrode. The deposition potential of the constant potential deposition method is -1.2v, and the time of the first electrodeposition reaction is 7 minutes; the cleaning method after the first electrodeposition reaction is distilled water (ultrasound 5min), anhydrous ethanol (ultrasound 5min), distilled water (ultrasound 5min) and 1mol / L hydrochloric acid (ultrasound 1min), distilled water (ultrasound 5min) in sequence; ultrasonic cleaning of the surface;

[0032] (2) immersing the nickel foam in a transition metal compound solution, performing a second electrodeposition reaction, washing and drying at 50° C. for 0.5 hour to obtain an alkaline zinc battery positive electrode material; the transition metal compound solution is a strong electrolyte, the cations in the transition metal compound solution are the same as those in step (1), and the transition metal compound solution is prepared by dissolving nickel nitrate hexahydrate and cobalt nitrate hexahydrate in 50 mL of distilled water in a mass ratio of 1:0.5, and the concentrations of nickel ions and cobalt ions are the same as those in step (1); the deposition potential of the constant potential deposition method is -1.2 V, and the time of the second electrodeposition reaction is 2 minutes.

[0033] Example 2

[0034] As a method for preparing an alkaline zinc battery positive electrode material according to an embodiment of the present invention, the only difference between this embodiment and embodiment 1 is:

[0035] In step (2), the mass ratio of nickel nitrate hexahydrate to cobalt nitrate hexahydrate in the transition metal compound solution is 1:1.

[0036] Example 3

[0037] As a method for preparing an alkaline zinc battery positive electrode material according to an embodiment of the present invention, the only difference between this embodiment and embodiment 1 is:

[0038] In step (2), the mass ratio of nickel nitrate hexahydrate to cobalt nitrate hexahydrate in the transition metal compound solution is 1:2.

[0039] Example 4

[0040] As a method for preparing an alkaline zinc battery positive electrode material according to an embodiment of the present invention, the only difference between this embodiment and embodiment 1 is:

[0041] In step (2), the mass ratio of nickel nitrate hexahydrate to cobalt nitrate hexahydrate in the transition metal compound solution is 1:3.

[0042] Example 5

[0043] As a method for preparing an alkaline zinc battery positive electrode material according to an embodiment of the present invention, the only difference between this embodiment and embodiment 1 is:

[0044] The alkaline zinc battery positive electrode material is prepared by a constant potential deposition method, wherein the first electrodeposition reaction is 3 minutes, and the deposition time of the second electrodeposition reaction is 5 minutes.

[0045] Example 6

[0046] As a method for preparing an alkaline zinc battery positive electrode material according to an embodiment of the present invention, the only difference between this embodiment and embodiment 4 is:

[0047] In step (1), the mass ratio of nickel nitrate hexahydrate to cobalt nitrate hexahydrate in the multi-metal phosphate solution is 1:3.

[0048] Example 7

[0049] As a method for preparing a positive electrode material for an alkaline zinc battery according to an embodiment of the present invention, the only difference between this embodiment and Example 1 is that the cations in the multi-metal phosphate solution include nickel, cobalt and iron; the multi-metal phosphate solution is configured by dissolving nickel nitrate hexahydrate, cobalt nitrate hexahydrate and ferric nitrate nonahydrate in 50 mL of distilled water in a mass ratio of 1:0.5:0.5, and adding sodium dihydrogen phosphate monohydrate to dissolve, and the mol ratio of dihydrogen phosphate ions to nickel ions is 2:1.

[0050] Comparative Example 1

[0051] As a method for preparing an alkaline zinc battery positive electrode material as a comparative example of the present invention, the only difference between this comparative example and Example 1 is that the cations in the multi-metal phosphate solution in step (1) do not include cobalt, and the content of cobalt nitrate is supplemented by nickel nitrate.

[0052] Comparative Example 2

[0053] As a method for preparing an alkaline zinc battery positive electrode material as a comparative example of the present invention, the only difference between this comparative example and Example 1 is that the cations in the multi-metal phosphate solution in step (1) do not include nickel, and the content of nickel nitrate is supplemented by cobalt nitrate.

[0054] Comparative Example 3

[0055] As a method for preparing an alkaline zinc battery positive electrode material as a comparative example of the present invention, the only difference between this comparative example and Example 1 is that the alkaline zinc battery positive electrode material is not prepared by the second electrodeposition reaction in step (2).

[0056] Experimental methods

[0057] 1. Electrochemical performance test

[0058] Alkaline zinc battery positive electrode materials were prepared according to Examples 1-7 and Comparative Examples 1-3. The test sample specifications were 1mm×10mm×20mm. In the electrochemical test, the prepared alkaline zinc battery positive electrode material was used as the working electrode, a high-purity zinc sheet with the same area as the working electrode was used as the counter electrode, a high-purity zinc wire was used as a custom reference electrode, and 1 mol / L potassium hydroxide was used as the electrolyte for constant current charge and discharge (GCD) test.

[0059] The discharge specific capacity results of the alkaline zinc battery positive electrode materials of Test Examples 1-7 and Comparative Examples 1-3 are shown in Table 1.

[0060] Table 1 Discharge specific capacity of alkaline zinc battery positive electrode materials

[0061]

[0062]

[0063] As can be seen from Table 1, the preparation method of the positive electrode material of an alkaline zinc battery of the present invention uses nickel foam as a substrate, and sequentially loads polymetallic phosphate and transition metal hydroxide by an electrodeposition method, and the ratio of the polymetallic phosphate and the transition metal hydroxide is controlled by the electrodeposition method; the selection of metal elements in the polymetallic phosphate and the regulation of the ratio provide more active sites, and the polymetallic phosphate serves as an intermediate layer between the transition metal hydroxide and the nickel foam, which synergistically improves the charge and discharge performance of the positive electrode material of the alkaline zinc battery, improves the capacity of the positive electrode material of the alkaline zinc battery, and makes it exhibit better energy storage performance as the positive electrode material of the alkaline zinc battery. At the same time, the preparation process of the present invention is simple, the material is cheap and easy to obtain, the cost is low, the time consumption is short, it is convenient for mass production, energy-saving and low-consumption, and it is green and pollution-free.

[0064] Figure 1 , Figure 2 It can be seen that in the CV test and the constant current charge and discharge test, the battery positive electrode material prepared in Example 3 of the present invention exhibits a charge storage performance that is better than that of Comparative Example 2. The discharge capacitance of the electrode material of Example 3 is much higher than that of the electrode material of Comparative Example 2; Figure 3 , Figure 4 It can be seen that the deposited materials are completely consistent in the two times before and after. Changing the deposition time, that is, changing the ratio of polymetallic phosphate and transition metal hydroxide, can change the energy storage performance of the electrode material. It can be seen that the battery positive electrode material of Example 5 of the present invention (relative to Example 1, the ratio of polymetallic phosphate and transition metal hydroxide is reduced) has an improvement in discharge specific capacity, a longer charge and discharge time, and better material energy storage performance.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing an alkaline zinc battery positive electrode material, characterized in that: The preparation method comprises the following steps: (1) immersing the nickel foam in a polymetallic phosphate solution, performing a first electrodeposition reaction and then washing; the anions in the polymetallic phosphate solution include phosphate, hydrogen phosphate, dihydrogen phosphate or metaphosphate; the cations in the polymetallic phosphate solution include nickel, cobalt, iron or copper and necessarily contain nickel; (2) immersing the nickel foam in a transition metal compound solution, performing a second electrodeposition reaction, and washing and drying to obtain an alkaline zinc battery positive electrode material; the transition metal compound solution is a strong electrolyte, and the cations in the transition metal compound solution are the same as those in step (1); The time ratio of the first electrodeposition reaction to the second electrodeposition reaction is 2:(0.5-4).

2. The method for preparing the positive electrode material of alkaline zinc battery according to claim 1, characterized in that: The cations in the polymetallic phosphate solution are nickel and cobalt.

3. The method for preparing the positive electrode material of alkaline zinc battery according to claim 1, characterized in that: The molar ratio of anions to nickel ions in the multi-metal phosphate solution is (1.8-2.2):

1.

4. The method for preparing the positive electrode material for alkaline zinc batteries according to claim 1, characterized in that: The electrodeposition reaction is a constant potential deposition method, the deposition potential of the constant potential deposition method is -0.6V to -1.5V, the time of the first electrodeposition reaction is 2 to 5 minutes, and the time of the second electrodeposition reaction is 4 to 8 minutes.

5. The method for preparing the positive electrode material for alkaline zinc batteries according to claim 4, characterized in that: The constant potential deposition method is carried out using a three-electrode system, which includes a working electrode, a counter electrode, and a reference electrode. The working electrode is nickel foam or nickel foam loaded with multi-metal phosphate material, the counter electrode is a platinum sheet, and the reference electrode is a silver chloride-silver chloride saturated potassium chloride electrode.

6. The method for preparing the positive electrode material for alkaline zinc batteries according to claim 1, characterized in that: The concentration of nickel ions in the multi-metal phosphate solution is 0.05 mol / L to 0.5 mol / L, and the concentration of nickel ions in the transition metal compound solution is 0.05 mol / L to 0.5 mol / L.

7. The method for preparing the positive electrode material of alkaline zinc battery according to claim 1, characterized in that: Step (1) cleaning the nickel foam; The methods for cleaning the nickel foam before step (1), cleaning after the first electrodeposition reaction, and cleaning after the second electrodeposition reaction are deionized water, anhydrous ethanol, deionized water, 0.8-1.5 mol / L hydrochloric acid, and deionized water ultrasonic cleaning, respectively.

8. The method for preparing the positive electrode material for alkaline zinc batteries according to claim 1, characterized in that: The cationic compound of the polymetallic phosphate solution is at least two of nickel acetate, cobalt acetate, iron acetate, nickel nitrate, cobalt nitrate, iron nitrate, copper nitrate, manganese nitrate, nickel chloride, cobalt chloride, iron chloride, copper chloride, and manganese chloride; the anionic compound of the polymetallic phosphate solution is potassium dihydrogen phosphate, ammonium phosphate, tricalcium phosphate, sodium hypophosphite, or sodium metaphosphate; The transition metal compound solution is at least two of nickel acetate, cobalt acetate, iron acetate, nickel nitrate, cobalt nitrate, iron nitrate, copper nitrate, manganese nitrate, nickel chloride, cobalt chloride, iron chloride, copper chloride, and manganese chloride.

9. An alkaline zinc battery positive electrode material prepared by the method for preparing an alkaline zinc battery positive electrode material according to any one of claims 1 to 7.

10. An alkaline zinc battery, characterized in that: The alkaline zinc battery comprises the alkaline zinc battery positive electrode material as claimed in claim 8.

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