Electrolytic copper foil preparation method based on pulse plating

Abstract

The application discloses a kind of electrolytic copper foil preparation methods based on pulse plating, comprising the following steps: selecting suitable electrolyte, and electrolyte is added to electrolytic cell;Set appropriate electrolyte flow rate;Access pulse power supply, set average current density to 20~50A / dm 2 , pulse width is 1~10ms, duty cycle is 1~30%, pulse waveform is rectangular wave;Start pulse power supply to start pulse electrolysis foil.This application can obtain fine-grained copper foil by controlling pulse parameters;This application can weaken hydrogen evolution by controlling pulse parameters, thereby reducing the generation of holes;Through the method of the application, the surface of copper foil is smooth and uniform, and defects are not easy to produce.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrolytic copper foil, in particular to a preparation method of electrolytic copper foil based on pulse electroplating. BACKGROUND

[0002] The electrolytic copper foil is a negative current collector widely used in the commercialized lithium battery. The copper foil current collector plays a role of collecting and transmitting electric charge and bearing the negative active material in the lithium ion battery. During the charging and discharging cycle of the lithium ion battery, the mechanical properties of the copper foil current collector are required due to the embedding and stripping of lithium ions in the negative electrode. Under the condition of certain thickness and mass, the development of copper foil with higher tensile strength and elongation is of great significance to improve the performance of the lithium battery. In addition, it has important value for the copper foil industry, energy storage equipment, electric vehicles and other industries. At present, the production of electrolytic copper foil in the industry is mainly based on direct current electroplating. When direct current electroplating is used, a thick diffusion layer is easily formed at the interface between the electrolyte and the cathode, which reduces the concentration of metal ions near the surface of the cathode, hinders the electrodeposition speed, and at this time, increasing the current density cannot improve the deposition speed, but aggravates hydrogen evolution, which reduces the current efficiency, and the plating layer appears hydrogen embrittlement, pinholes, scorching and other phenomena, and reduces the quality of the plating layer. SUMMARY

[0003] In view of the above technical problems in the related art, the present application provides a preparation method of electrolytic copper foil based on pulse electroplating, which can solve the above problems.

[0004] To achieve the above technical purposes, the technical scheme of the present application is as follows:

[0005] A preparation method of electrolytic copper foil based on pulse electroplating, comprising the following steps:

[0006] S100, selecting a suitable electrolyte and adding the electrolyte into an electrolytic cell;

[0007] S200, setting a suitable electrolyte flow rate;

[0008] S300, connecting a pulse power supply, setting the average current density to 20-50 A / dm 2 , the pulse width to 1-10 ms, the duty cycle to 1-30%, and the pulse waveform to a rectangular wave;

[0009] S400, starting the pulse power supply to start pulse electrolysis of the foil.

[0010] Further, the electrolyte in step S100 is an electrolyte containing copper ions and necessary additives with a temperature of 40-70 DEG C, and the PH of the electrolyte is greater than 3.

[0011] Further, the content of copper ions in the electrolyte is 10-100 g / L, and the additives include organic matter (R-SH) containing sulfydryl, polyether organic matter, surfactant and hydrochloric acid.

[0012] Further, the rotating roller prepared from titanium metal is used as the cathode in the electrolytic cell in step S100, and the surface roughness Ra of the cathode is less than 1 μm.

[0013] Further, the flow rate of the electrolyte in step S200 is 30-60 m 3 / h.

[0014] The application has the following advantages: the application can obtain fine-grained copper foil by controlling pulse parameters; the application can weaken hydrogen evolution and reduce the generation of holes; the copper foil surface is smooth and uniform and defects are not easy to occur. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] The present application will be further described in detail below according to the drawings.

[0017] Figure 1 It is a pulse waveform schematic diagram of the pulse power described in the embodiments of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0019] According to the present application, a kind of electrolytic copper foil preparation method based on pulse plating is disclosed, first, electrolyte containing copper ions is injected into electrolytic cell, the concentration of copper ions is 10-100 g / L, pH is above 3, then the temperature of electrolyte is heated to 40-70 ℃, the flow rate is set to 30-60 m 3 / h, preferably other necessary additives are injected into the electrolytic cell, the amount is set according to the requirement, then the electrolyte preparation is completed, wherein the necessary additives include mercapto-containing organic matter (R-SH), polyether organic matter, surfactant, hydrochloric acid, the mercapto-containing organic matter (R-SH) is one or more of the group consisting of mercaptoethanol, mercaptoacetic acid, mercaptoacetic acid ethyl ester, mercaptoethylamine and mercaptopropyl trimethoxysilane, the polyether organic matter is one or more of block polyether L35 (DOW company number, the same below), block polyether L45 and block polyether L61, and the surfactant is sodium dodecyl sulfonate and / or sodium dodecyl sulfate.

[0020] The pulse power supply is accessed (the power supply can adopt a water-cooled pulse rectifier), the average current density is set to 20-50 A / dm 2 , the pulse width is 1-10 ms, the duty cycle is 1-30%, and the pulse waveform is a rectangular wave. Specifically, one cycle is formed by each time the current is turned on and turned off, and the current conduction time in one cycle is 1-10 ms, accounting for 1-30% of the entire cycle length. As shown in Figure 1 , it is a schematic diagram of the rectangular wave used, the horizontal coordinate t is time, and the vertical coordinate A is current. When the current is turned on, it has a very high pulse current density, and the nucleation speed is greater than the growth speed. When the current is turned off, the grain growth speed slows down, and at the same time, the copper ions in the enrichment area diffuse to the poor area, weakening the concentration polarization. This way of controlling the periodic on-off of the current makes the grain nucleation speed much greater than the growth speed, making the crystallization fine, and at the same time, weakening the concentration polarization, making the grain deposition uniform.

[0021] After the pulse power supply is turned on, electrolysis is carried out by applying a pulse current to the anode. During the electrolysis process, copper ions are reduced to the cathode surface in a periodic manner, forming a dense copper foil, and the surface shows a smooth and uniform state. The copper foil is deposited on the surface of the rotating cathode roller, and the copper foil on the roller surface is continuously stripped and wound by the stripping roller and the winding roller, realizing continuous electrolysis. The copper foil prepared by the method has the following characteristics: the average equivalent circle diameter of about 3500 grains in the cross section of the copper foil is 0.6 μm, the twin crystal ratio is 40%, the tensile strength is 750-800 MPa, the elongation is 5-6%, the gloss is 110-140 GS, the foil surface has no light transmission point, and is uniform and dense.

[0022] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing electrolytic copper foil based on pulse electroplating, characterized in that, Includes the following steps: S100. Select a suitable electrolyte and add it to the electrolytic cell; The electrolyte in step S100 is an electrolyte containing copper ions and necessary additives with a temperature between 40 and 70°C, and the pH of the electrolyte is greater than 3. S200, Set a suitable electrolyte flow rate; S300, connect to pulse power supply, pulse waveform is rectangular wave, set average current density to 20-50A / dm². 2 The pulse width is 1–10 ms, and the duty cycle is 1–30%. S400: Start the pulse power supply to begin pulse electrolysis for foil production. When the current is on, there is a very high pulse current density, and the nucleation rate is greater than the growth rate. When the current is off, the grain growth rate slows down, and copper ions in the enriched area diffuse to the depleted area, reducing concentration polarization. This method of controlling the periodic on and off of the current makes the grain nucleation rate much greater than the growth rate, resulting in fine crystals. At the same time, it reduces concentration polarization, resulting in uniform grain deposition. The copper foil prepared by the method has the following characteristics: a twinning ratio of 40% and a tensile strength of 750–800 MPa.

2. The method for preparing electrolytic copper foil based on pulse electroplating according to claim 1, characterized in that, The electrolyte contains 10–100 g / L of copper ions, and the additives include thiol-containing organic compounds R-SH, polyether organic compounds, surfactants, and hydrochloric acid.

3. The method for preparing electrolytic copper foil based on pulse electroplating according to claim 1, characterized in that, In step S100, a rotating roller made of titanium metal is used as the cathode in the electrolytic cell. The surface roughness of the cathode is Ra < 1 μm. Multiple insoluble substrates that are fixed and partially surround the cathode are used as the anode.

4. The method for preparing electrolytic copper foil based on pulse electroplating according to claim 1, characterized in that, The electrolyte flow rate in step S200 is 30–60 m / s. 3 / h.

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