Electrolyte for preparing nickel-iron alloy foil and application

Abstract

The invention relates to the technical field of alloy foil manufacturing, in particular to electrolyte for preparing nickel-iron alloy foil and application. According to the electrolyte for preparing the nickel-iron alloy foil and the application, the electrolyte comprises 200-300 parts by mass of a first metal nickel salt, 20-80 parts by mass of a second metal nickel salt, 20-80 parts by mass of a metal iron salt, 2-10 parts by mass of a reducing agent, 20-60 parts by mass of an acid-base regulator, 0.5-1.5 parts by mass of a leveling agent, 2-10 parts by mass of a brightening agent and 0.2-0.5 part by mass of a wetting agent, the second metal nickel salt or the metal iron salt is chlorate; by controlling the proportion of the chloride ion concentration, the nickel ion concentration and the ferrous ion concentration in the electrolyte and controlling the adding proportion of the reducing agent, the acid-base regulator, the leveling agent, the brightening agent and the wetting agent, the tensile strength and the ductility of the nickel-iron alloy foil can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of alloy foil manufacturing, and in particular to an electrolyte for preparing nickel-iron alloy foil and its application. Background Art

[0002] Nickel-iron alloy foil is an alloy material with excellent electrical and mechanical properties, corrosion resistance, and soft magnetic properties. It is widely used in the electronics and electrical industries, especially in communications, radar, electronic computers, automatic control instruments, and other fields, where it has become an indispensable component. With the advancement of science and technology, the materials required in many high-tech fields are developing in a lightweight and thinner direction. In recent years, electrodeposited micron-sized nickel-iron alloy foil has become a research hotspot for battery current collector materials due to its lightness, excellent physical properties, and good conductivity. Nickel-iron alloy foil prepared using electrodeposition technology has the advantages of isotropic physical properties, easy-to-control thickness, and low production cost. Research on electrodeposited nickel-iron alloy foil has very broad application prospects.

[0003] Currently, how to improve the tensile strength and elongation of nickel-iron alloy foil has become a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0004] Based on this, the present application provides an electrolyte for preparing nickel-iron alloy foil and its application, so as to solve the technical problem of how to improve the tensile strength and elongation of nickel-iron alloy foil in the prior art.

[0005] In a first aspect, an embodiment of the present application provides an electrolyte for preparing nickel-iron alloy foil, comprising 200 to 300 parts by mass of a first metal nickel salt, 20 to 80 parts by mass of a second metal nickel salt, 20 to 80 parts by mass of a metal iron salt, 2 to 10 parts by mass of a reducing agent, 20 to 60 parts by mass of an acid-base regulator, 0.5 to 1.5 parts by mass of a leveling agent, 2 to 10 parts by mass of a brightener, and 0.2 to 0.5 parts by mass of a wetting agent, wherein the second metal nickel salt or the metal iron salt is a chloride salt.

[0006] Optionally, the first metal nickel salt is nickel sulfate hexahydrate, the second metal nickel salt is nickel chloride hexahydrate, and the metal iron salt is ferrous sulfate heptahydrate.

[0007] Optionally, the reducing agent includes ascorbic acid, the acid-base regulator includes boric acid, the leveling agent includes Janus Green, the brightening agent includes sodium saccharin, and the wetting agent includes sodium lauryl sulfate or polyethylene glycol.

[0008] In a second aspect, an embodiment of the present application provides a method for preparing a nickel-iron alloy foil, comprising:

[0009] The electrolyte for preparing the nickel-iron alloy foil according to any one of claims 1 to 3 is supplied between the anode plate and the cathode roller, and a voltage is applied between the anode plate and the cathode roller to electrolyze the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0010] Optionally, the current density applied between the anode plate and the cathode roller during electrolysis is 10 to 28 A / dm 2 .

[0011] Optionally, the pH value of the electrolyte used to prepare the nickel-iron alloy foil during electrolysis is 2-5.

[0012] Optionally, the temperature of the electrolyte for preparing the nickel-iron alloy foil during electrolysis is 50° C. to 60° C.

[0013] Optionally, the average roughness of the cathode roller is 0.12-0.17 μm, the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min, the cathode roller is a titanium roller, and the anode plate is an iridium-plated titanium plate.

[0014] In a third aspect, an embodiment of the present application provides a nickel-iron alloy foil, which is obtained according to the above-mentioned method for preparing the nickel-iron alloy foil.

[0015] In a fourth aspect, an embodiment of the present application provides a negative electrode material for a lithium-ion battery, comprising the above-mentioned nickel-iron alloy foil.

[0016] The electrolyte and application for preparing nickel-iron alloy foil in the embodiment of the present application include 200-300 parts by mass of a first metal nickel salt, 20-80 parts by mass of a second metal nickel salt, 20-80 parts by mass of a metal iron salt, 2-10 parts by mass of a reducing agent, 20-60 parts by mass of an acid-base regulator, 0.5-1.5 parts by mass of a leveling agent, 2-10 parts by mass of a brightener and 0.2-0.5 parts by mass of a wetting agent, wherein the second metal nickel salt or the metal iron salt is a chloride salt; by controlling the ratio of the chloride ion concentration, the nickel ion concentration and the ferrous ion concentration in the electrolyte, and controlling the addition ratio of the reducing agent, the acid-base regulator, the leveling agent, the brightener and the wetting agent, it is beneficial to improve the tensile strength and elongation of the nickel-iron alloy foil. DETAILED DESCRIPTION

[0017] To facilitate understanding of the present application, a more comprehensive description of the present application is provided below. Preferred embodiments of the present application are provided in the specification. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0018] It should be noted that when an element is referred to as being “fixed to” another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or there may be an intermediate element.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0020] One embodiment of the present application provides an electrolyte for preparing nickel-iron alloy foil, comprising 200-300 parts by mass of a first metal nickel salt, 20-80 parts by mass of a second metal nickel salt, 20-80 parts by mass of a metal iron salt, 2-10 parts by mass of a reducing agent, 20-60 parts by mass of an acid-base regulator, 0.5-1.5 parts by mass of a leveling agent, 2-10 parts by mass of a brightener, and 0.2-0.5 parts by mass of a wetting agent, wherein the second metal nickel salt or the metal iron salt is a chloride salt.

[0021] Among them, the first metal nickel salt and the second metal nickel salt are used to provide metal nickel ions during the electrolysis process, and the metal iron salt is used to provide metal ferrous ions during the electrolysis process; the second metal nickel salt or metal iron salt is used to provide chloride ions during the electrolysis process, and the chloride ions can reduce the valence state of the metal active point. The chloride ions provided by the second metal nickel salt or metal iron salt are used to reduce the electroplating activeness during the electrolysis process; the reducing agent is used to prevent the oxidation of ferrous ions during the electrolysis process, and the acid-base regulator is used to control the electrolytic acidic environment during the electrolysis process; the leveling agent is used to improve the flatness of the nickel-iron alloy foil during the electrolysis process, so that the surface of the nickel-iron alloy foil obtained by electrolytic deposition is smoother; the brightener is adsorbed on the surface of the cathode (nickel-iron alloy foil), inhibits the rapid and disordered deposition of metal ions, promotes the uniform formation of crystal nuclei, thereby refining the coating grains and making the surface denser and smoother; the wetting agent can significantly reduce the surface tension of the electrolyte, making it easier to wet the cathode (nickel-iron alloy foil) surface, that is, reduce the surface tension of the nickel-iron alloy foil, so that the liquid can spread on the surface of the nickel-iron alloy foil to wet the nickel-iron alloy foil.

[0022] In addition, chloride ions are anode activators and can form complexes with metal ions FeCl + and NiCl + , which can make the metal ion equilibrium potential move negatively, eliminate the stress of the nickel-iron alloy foil formed by electrolytic deposition, help the anode dissolve, and produce synergistic effects with additives. For example, it can coordinate with the brightener to make the nickel-iron alloy foil bright, and coordinate with the leveling agent to make the nickel-iron alloy foil level.

[0023] In this embodiment, by controlling the ratio of chloride ion concentration, nickel ion concentration and ferrous ion concentration in the electrolyte, and controlling the addition ratio of reducing agent, acid-base regulator, leveling agent, brightener and wetting agent, it is beneficial to improve the tensile strength and elongation of nickel-iron alloy foil.

[0024] In addition, the iron content in the electrolyte formula is relatively high, which is conducive to increasing the iron content in the nickel-iron alloy foil. While the iron content is increased and the nickel content is reduced, the obtained nickel-iron alloy foil still has good tensile strength and elongation.

[0025] Illustratively, in the above-mentioned electrolyte for preparing nickel-iron alloy foil, the concentration of the first metal nickel salt is 200-300 g / L, the concentration of the second metal nickel salt is 20-80 g / L, the concentration of the metal iron salt is 20-80 g / L, the concentration of the reducing agent is 2-10 g / L, the concentration of the acid-base regulator is 20-60 g / L, the concentration of the leveling agent is 0.5-1.5 g / L, the concentration of the brightener is 2-10 g / L, and the concentration of the wetting agent is 0.2-0.5 g / L.

[0026] Optionally, the first metal nickel salt is nickel sulfate hexahydrate (NiSO4·6H20), the second metal nickel salt is nickel chloride hexahydrate (NiCl2·6H20), and the metal iron salt is ferrous sulfate heptahydrate (FeSO4·7H20).

[0027] In this embodiment, the second metal nickel salt provides chloride ions to control the concentration of chloride ions in the electrolyte within a corresponding range, thereby reducing the activeness of electrodeposition and producing a synergistic effect with the additive, thereby further improving the quality of the nickel-iron alloy foil.

[0028] Optionally, the reducing agent includes ascorbic acid, the acid-base adjusting agent includes boric acid, the leveling agent includes Janus Green, the brightening agent includes sodium saccharin, and the wetting agent includes sodium lauryl sulfate or polyethylene glycol.

[0029] The present application provides a method for preparing a nickel-iron alloy foil according to an embodiment, comprising the steps of:

[0030] Step S11: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0031] The electrolyte used to prepare the nickel-iron alloy foil is as described in the above embodiments, which will not be described in detail here.

[0032] Step S12: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0033] During the electrolysis process, nickel ions and ferrous ions in the electrolyte are deposited on the surface of the cathode roller to form nickel-iron alloy foil, which is then peeled off from the cathode roller and enters subsequent processing steps.

[0034] In this embodiment, by controlling the ratio of chloride ion concentration, nickel ion concentration and ferrous ion concentration in the electrolyte, and controlling the addition ratio of reducing agent, acid-base regulator, leveling agent, brightener and wetting agent, it is beneficial to improve the tensile strength and elongation of nickel-iron alloy foil.

[0035] As an embodiment, the current density applied between the anode plate and the cathode roller during electrolysis is 10 to 28 A / dm 2 .

[0036] In some embodiments, the current density applied between the anode plate and the cathode roller during electrolysis is 10 to 16 A / dm 2 .

[0037] In this embodiment, electrolysis is performed at a relatively low current density, resulting in relatively slow deposition. This slow deposition allows for full grain growth, resulting in a uniform and dense structure. Furthermore, the use of a relatively low current density, combined with controlled brightener dosage, allows for full grain growth, resulting in a uniform and dense structure, while mitigating the increased surface roughness of the gold foil caused by low current density, ultimately maintaining the alloy foil's surface roughness within a reasonable range.

[0038] As an embodiment, the pH value of the electrolyte used to prepare the nickel-iron alloy foil during electrolysis is 2-5.

[0039] In this embodiment, the use of the acid-base regulator can keep the pH value of the electrolyte within the above range during the electrolysis process.

[0040] As an embodiment, the temperature of the electrolyte used to prepare the nickel-iron alloy foil during electrolysis is 50° C. to 60° C.

[0041] In this embodiment, controlling the electrolysis temperature within the above range is beneficial to increasing the density of the alloy foil coating while ensuring the deposition rate.

[0042] As an embodiment, the average roughness of the cathode roller can be 0.12 to 0.17 μm. In this embodiment, controlling the roughness of the cathode roller within the above range is beneficial to the formation of the crystalline structure of the first 0 to 1.5 μm thickness of the electrolytically obtained alloy foil.

[0043] In some embodiments, the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0044] In some embodiments, the cathode roller is a titanium roller, and the anode plate is an iridium-plated titanium plate, that is, the anode plate is formed by plating a metal iridium layer on the surface of a titanium plate.

[0045] An embodiment of the present application provides a nickel-iron alloy foil, which is obtained according to the above-mentioned method for preparing the nickel-iron alloy foil.

[0046] An embodiment of the present application provides a negative electrode material for a lithium-ion battery, comprising the above-mentioned nickel-iron alloy foil.

[0047] Example 1

[0048] This embodiment provides a method for preparing nickel-iron alloy foil, comprising the steps of:

[0049] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0050] Table 1 Content of each component in Example 1

[0051]

[0052] The components of the electrolyte used to prepare the nickel-iron alloy foil are shown in Table 1.

[0053] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0054] The current density applied between the anode plate and the cathode roller during electrolysis is 14A / dm 2 The electrolysis temperature is 55°C, the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0055] Example 2

[0056] This embodiment provides a method for preparing nickel-iron alloy foil, comprising the steps of:

[0057] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0058] Table 2 Content of each component in Example 2

[0059]

[0060] The components of the electrolyte used to prepare the nickel-iron alloy foil are shown in Table 2.

[0061] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0062] The current density applied between the anode plate and the cathode roller during electrolysis is 14A / dm 2 The electrolysis temperature is 55°C, the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0063] Example 3

[0064] This embodiment provides a method for preparing nickel-iron alloy foil, comprising the steps of:

[0065] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0066] Table 3 Content of each component in Example 3

[0067]

[0068] The components of the electrolyte used to prepare the nickel-iron alloy foil are shown in Table 3.

[0069] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0070] The current density applied between the anode plate and the cathode roller during electrolysis is 14A / dm 2 The electrolysis temperature is 55°C, the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0071] Example 4

[0072] This embodiment provides a method for preparing nickel-iron alloy foil, comprising the steps of:

[0073] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0074] Table 4 Content of each component in Example 4

[0075]

[0076] The components of the electrolyte used to prepare the nickel-iron alloy foil are shown in Table 4.

[0077] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0078] The current density applied between the anode plate and the cathode roller during electrolysis is 20A / dm 2 The electrolysis temperature is 55°C, the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0079] Example 5

[0080] This embodiment provides a method for preparing nickel-iron alloy foil, comprising the steps of:

[0081] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0082] Table 5 Content of each component in Example 5

[0083]

[0084] The components of the electrolyte used to prepare the nickel-iron alloy foil are shown in Table 5.

[0085] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0086] The current density applied between the anode plate and the cathode roller during electrolysis is 14A / dm 2 The electrolysis temperature is 55°C, the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0087] Example 6

[0088] This embodiment provides a method for preparing nickel-iron alloy foil, comprising the steps of:

[0089] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0090] Table 6 Content of each component in Example 6

[0091]

[0092] The components of the electrolyte used to prepare the nickel-iron alloy foil are shown in Table 6.

[0093] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0094] The current density applied between the anode plate and the cathode roller during electrolysis is 14A / dm 2 The electrolysis temperature is 55°C, the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0095] Example 7

[0096] This embodiment provides a method for preparing nickel-iron alloy foil, comprising the steps of:

[0097] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0098] Table 7 Content of each component in Example 7

[0099]

[0100] The components of the electrolyte used to prepare the nickel-iron alloy foil are shown in Table 7.

[0101] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0102] The current density applied between the anode plate and the cathode roller during electrolysis is 14A / dm 2 The electrolysis temperature is 55°C, the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0103] Example 8

[0104] This embodiment provides a method for preparing nickel-iron alloy foil, comprising the steps of:

[0105] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0106] Table 8 Content of each component in Example 8

[0107]

[0108] The components of the electrolyte used to prepare the nickel-iron alloy foil are shown in Table 8.

[0109] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0110] The current density applied between the anode plate and the cathode roller during electrolysis is 14A / dm 2 The electrolysis temperature is 55°C, the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min.

[0111] The thickness of the nickel-iron alloy foil prepared in Examples 1 to 8 is 6 μm. The experimental results of Examples 1 to 8 are shown in Table 9.

[0112] Table 9 Experimental results of Examples 1 to 8

[0113]

[0114] As shown in Table 9, the tensile strength of the nickel-iron alloy foil can reach above 1635 MPa; and the elongation of the nickel-iron alloy foil can reach above 3.55%.

[0115] Example 9 to Example 18

[0116] A method for preparing nickel-iron alloy foil comprises the following steps:

[0117] Step 1: providing the above-mentioned electrolyte for preparing nickel-iron alloy foil.

[0118] Table 10 Content of ingredients in Examples 9 to 18

[0119]

[0120] Step 2: supplying the electrolyte for preparing the nickel-iron alloy foil between the anode plate and the cathode roller, applying voltage between the anode plate and the cathode roller, electrolyzing the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

[0121] The electrolysis temperature is 55° C., the pH value during electrolysis is 3, and the rotation speed of the cathode roller during electrolysis is 7.5 to 8.4 m / min.

[0122] The current density applied between the anode plate and the cathode roller during electrolysis is shown in Table 11.

[0123] The thickness of the nickel-iron alloy foil prepared in Examples 9 to 18 is 6 μm. The experimental results of Examples 9 to 18 are shown in Table 11.

[0124] Table 11 Current density and experimental results of Examples 9 to 18

[0125]

[0126] The thickness of the nickel-iron alloy foil prepared in Examples 9 to 18 was 6 μm, and the current density applied between the anode plate and the cathode roller during electrolysis was 10 to 28 A / dm 2 When the tensile strength of the nickel-iron alloy foils prepared in Examples 9 to 18 can reach more than 1300 MPa, the elongation of the nickel-iron alloy foils prepared in Examples 9 to 18 can reach more than 2.77%; the current density applied between the anode plate and the cathode roller during electrolysis is 16 to 18 A / dm 2 When the tensile strength of the nickel-iron alloy foils prepared in Examples 11 to 13 can reach more than 1800 MPa, the elongation of the nickel-iron alloy foils prepared in Examples 11 to 13 can reach more than 5.97%.

[0127] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] The above embodiments merely represent preferred embodiments of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An electrolyte for preparing nickel-iron alloy foil, characterized in that The invention comprises 200 to 300 parts by mass of a first metal nickel salt, 20 to 80 parts by mass of a second metal nickel salt, 20 to 80 parts by mass of a metal iron salt, 2 to 10 parts by mass of a reducing agent, 20 to 60 parts by mass of an acid-base regulator, 0.5 to 1.5 parts by mass of a leveling agent, 2 to 10 parts by mass of a brightener and 0.2 to 0.5 parts by mass of a wetting agent, wherein the second metal nickel salt or the metal iron salt is a chloride salt.

2. The electrolyte for preparing nickel-iron alloy foil according to claim 1, characterized in that The first metal nickel salt is nickel sulfate hexahydrate, the second metal nickel salt is nickel chloride hexahydrate, and the metal iron salt is ferrous sulfate heptahydrate.

3. The electrolyte for preparing nickel-iron alloy foil according to claim 1, characterized in that The reducing agent includes ascorbic acid, the acid-base adjusting agent includes boric acid, the leveling agent includes Janus Green, the brightening agent includes sodium saccharin, and the wetting agent includes sodium lauryl sulfate or polyethylene glycol.

4. A method for preparing nickel-iron alloy foil, characterized in that: include: The electrolyte for preparing the nickel-iron alloy foil according to any one of claims 1 to 3 is supplied between the anode plate and the cathode roller, and a voltage is applied between the anode plate and the cathode roller to electrolyze the electrolyte for preparing the nickel-iron alloy foil to form the nickel-iron alloy foil on the surface of the cathode roller.

5. The method for preparing the nickel-iron alloy foil according to claim 4, wherein: The current density applied between the anode plate and the cathode roller during electrolysis is 10 to 28 A / dm 2 .

6. The method for preparing the nickel-iron alloy foil according to claim 4, wherein: During electrolysis, the pH value of the electrolyte used to prepare the nickel-iron alloy foil is 2-5.

7. The method for preparing nickel-iron alloy foil according to claim 4, wherein: The temperature of the electrolyte for preparing the nickel-iron alloy foil during electrolysis is 50° C. to 60° C.

8. The method for preparing nickel-iron alloy foil according to claim 4, wherein: The average roughness of the cathode roller is 0.12-0.17 μm, the rotation speed of the cathode roller during electrolysis is 7.5-8.4 m / min, the cathode roller is a titanium roller, and the anode plate is an iridium-plated titanium plate.

9. A nickel-iron alloy foil, characterized in that The nickel-iron alloy foil is obtained according to the method for preparing the nickel-iron alloy foil according to any one of claims 4 to 8.

10. A lithium ion battery negative electrode material, characterized in that: The nickel-iron alloy foil according to claim 9 is included.

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