A negative electrode current collector, a method for manufacturing the same, and an application thereof

Abstract

This invention belongs to the field of energy storage technology and discloses a negative electrode current collector, its preparation method, and its application. The preparation method of the negative electrode current collector of this invention includes the following steps: S1, preparing an electrolyte; the electrolyte includes copper ions, sulfuric acid, chloride ions, and composite additives; S2, using an alternating forward and reverse pulse electrodeposition process, electrodepositing the electrolyte on the cathode, and during the reverse pulse phase, adding a graphene oxide dispersion to the electrolyte stepwise, so that the graphene oxide is embedded in the copper deposition layer, obtaining a composite copper foil; S3, passivating and anti-oxidation treatment of the composite copper foil, washing, drying, and winding to obtain a negative electrode current collector with high mechanical properties. The preparation method of this invention achieves uniform embedding and orientation distribution of graphene oxide in a copper matrix, and the resulting negative electrode current collector possesses high tensile strength, high elongation, moderate surface roughness, high elastic modulus, high peel strength, and corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to a negative electrode current collector, its preparation method, and its application. Background Technology

[0002] Copper foil, as a key component of the negative electrode current collector in semi-solid / solid batteries, directly affects the battery's energy density, cycle stability, and safety. In recent years, with the continuous improvement of driving range and safety performance requirements in the new energy vehicle industry, the negative electrode current collectors for semi-solid / solid batteries are developing towards higher strength (600-700MPa), higher elongation (≥5%), and greater corrosion resistance. Currently, DC electrolytic copper foil is mainly used as the negative electrode current collector in industry. This material is prepared based on a DC constant current electrodeposition process and is the most mature current collector material used in liquid lithium-ion batteries. However, electrolytic copper foil prepared by traditional DC electroplating processes faces a series of key contradictions in meeting the aforementioned development needs: First, while existing organic additives (such as sodium polydisulfide dipropane sulfonate and mercaptopropane sulfonate) can improve the tensile strength of copper foil to some extent, they can usually only reach 300-450 MPa and will cause the elongation to drop to below 5%, or even below 3%. This makes the copper foil prone to cracking, strip breakage or active material shedding during negative electrode slurry coating, rolling and battery charge and discharge volume changes, which seriously affects the battery manufacturing yield and service reliability.

[0003] Secondly, to improve the adhesion between the negative electrode active material (such as graphite, silicon carbide) and the copper foil, the current collector surface usually needs to have a high roughness (such as a ten-point average roughness Rz > 3.0 μm) to enhance the physical anchoring effect. However, under the traditional DC electroplating process, a high roughness will be accompanied by uneven distribution of internal stress in the copper foil, resulting in local stress concentration, which will weaken the bending resistance and interface stability of the copper foil. In practical applications, in order to control the stress concentration problem, the surface roughness Rz is usually limited to below 2.5 μm, but this sacrifices the bonding strength with the active material, resulting in increased solid-solid interface contact resistance and easy peeling of the active layer.

[0004] Third, during continuous electroplating production, additive components are prone to decomposition or polymerization reactions due to the influence of current, temperature and impurity ions, making it difficult to maintain their concentration precisely. This results in significant fluctuations in the performance of different batches of copper foil. Furthermore, when additive decomposition products accumulate, they not only weaken the original grain refinement or leveling effect, but may also introduce harmful impurities, causing uncontrollable deterioration in the mechanical properties and corrosion resistance of the copper foil.

[0005] In recent years, existing technologies have attempted to introduce nano-reinforcing phases (such as graphene and carbon nanotubes) into copper foil in order to simultaneously improve strength and elongation. However, in actual DC electroplating systems, nanomaterials such as graphene are prone to agglomeration due to their large specific surface area and high surface energy. They are difficult to disperse uniformly in the electroplating solution and effectively embed into the copper lattice or grain boundaries. This uneven distribution leads to a highly random reinforcement effect, and even the formation of stress concentration points due to local agglomeration, which reduces the overall performance of the copper foil. Similarly, the dispersion stability problem of carbon nanotubes in the copper electrodeposition process has not been effectively solved.

[0006] Furthermore, unlike traditional liquid lithium batteries, semi-solid / solid batteries have a solid-solid contact interface between their negative electrode and current collector. In order to reduce the interface impedance and maintain the structural integrity during cycling, a high compaction pressure needs to be applied to the current collector. Ordinary electrolytic copper foil has limited bending resistance (few repeated bending cycles and weak fatigue resistance). Under the periodic stress caused by high compaction at the solid-solid interface and electrochemical volume changes, microcracks are prone to propagate or even break, which cannot meet the long-term service reliability requirements of the current collector in semi-solid / solid batteries.

[0007] In summary, existing electrolytic copper foil preparation technologies cannot simultaneously achieve high tensile strength, high elongation, and controllable surface roughness Rz. They also fail to effectively address the problem of uniform dispersion of graphene and other nano-reinforcing phases in the copper matrix and the stringent requirements of solid-solid bonding for bending resistance. Therefore, it is urgent to develop a novel negative electrode current collector preparation technology to overcome the above-mentioned technical bottlenecks and meet the development needs of high-performance semi-solid / solid batteries. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a negative electrode current collector, its preparation method, and its application.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for preparing a negative electrode current collector, comprising the following steps: S1. Prepare the electrolyte; The electrolyte includes copper ions, sulfuric acid, chloride ions, and composite additives; The composite additive includes an accelerator, an inhibitor, a wetting agent, and a graphene oxide dispersion; The wetting agent includes sodium thiazolinyl dithiopropane sulfonate and / or thiazolin-2-thione; and in the electrolyte, the concentration of the wetting agent is 10 mg / L-30 mg / L; S2. Using a pulse electrodeposition process with alternating forward and reverse pulses, the electrolyte is electrodeposited on the cathode. During the reverse pulse phase, graphene oxide dispersion is added to the electrolyte in steps to embed the graphene oxide into the copper deposition layer, thereby obtaining a composite copper foil. S3. The composite copper foil is passivated and subjected to anti-oxidation treatment, washed, dried and wound up to obtain a negative electrode current collector.

[0010] The preparation method of the present invention achieves highly uniform embedding and orientation distribution of graphene oxide in a copper matrix by adding graphene oxide dispersion stepwise in the reverse pulse stage and in combination with a specific composite additive system. The prepared negative electrode current collector has high tensile strength, high elongation, moderate surface roughness, high elastic modulus, high peel strength and excellent corrosion resistance.

[0011] Specifically, this invention first constructs a ternary synergistic composite additive system of "accelerator + inhibitor + wetting agent". The accelerator selectively adsorbs on specific crystal planes on the cathode surface, reducing the activation energy barrier for copper ion reduction and promoting rapid copper deposition and grain refinement. The inhibitor inhibits excessive copper growth through physical adsorption or complexation, inducing copper grains to grow along a specific orientation. The wetting agent forms an oriented adsorption layer on the copper surface through its unique heterocyclic structure. On the one hand, it reduces interfacial tension, promotes the dispersion and stability of graphene in the aqueous phase, and on the other hand, it provides "anchoring points" for graphene sheets, guiding graphene to distribute in a parallel orientation along the copper deposition surface. Thus, the three work synergistically to form a finely controlled network of "acceleration-inhibition-orientation", which inhibits the growth of copper grains in the vertical direction and forms a dense stack in the horizontal direction. This maximizes the mechanical strength and corrosion resistance while ensuring the good flexibility of the copper foil.

[0012] Secondly, the pulsed electrodeposition process of this invention utilizes the anodic dissolution effect during reverse conduction to selectively dissolve the sharp protrusions and excessively fast-growing areas on the surface of the deposited layer, thereby achieving leveling and stress release of the copper deposited layer. Furthermore, this invention adds graphene oxide dispersion in stages during the reverse pulse phase. The core mechanism is that the copper ion consumption rate near the cathode interface decreases and the diffusion layer thickness decreases during the reverse pulse. At this time, the graphene oxide sheets have higher diffusion flux and interface collision probability, enabling them to be transported to the growth interface and embedded in the deposited layer more efficiently. At the same time, the brief "pause" state of the reverse pulse weakens the competitive adsorption between the additive and the graphene oxide, avoiding the defect of excessive coating of graphene oxide by the additive in the traditional co-deposition process, which results in the loss of its reinforcing effect. This achieves a uniform distribution of graphene oxide in the copper deposited layer in a monodisperse or few-layer state, effectively solving the technical problems of easy agglomeration and uneven distribution of graphene oxide.

[0013] In a preferred embodiment of the method for preparing the negative electrode current collector according to the present invention, in step S1, the concentration of copper ions in the electrolyte is 80 g / L-120 g / L, the concentration of sulfuric acid is 80 g / L-120 g / L, and the concentration of chloride ions is 20 mg / L-40 mg / L.

[0014] Preferably, in step S1, the concentration of copper ions in the electrolyte is 90 g / L, the concentration of sulfuric acid is 120 g / L, and the concentration of chloride ions is 20 mg / L.

[0015] In a preferred embodiment of the method for preparing the negative electrode current collector according to the present invention, in step S1, the accelerator includes at least one of polydithiodipropanesulfonic acid (SPS), sodium 3-mercapto-1-propanesulfonate (MPS), sodium N,N-dimethyl-dithiocarbonylpropanesulfonate (DPS), thiourea propyl sulfate (UPS), sodium N-(3-sulfopropyl)-saccharin (SAPS), and polyoxyethylene alkylamine sulfonate (JPS); the inhibitor includes at least one of collagen, gelatin, bone glue, and aliphatic polyoxyethylene ether sulfonate; the graphene oxide dispersion is a graphene oxide dispersion that has undergone dispersion treatment; and the average sheet diameter of the graphene oxide is 0.5 μm-2 μm.

[0016] The present invention uses the aforementioned accelerator and inhibitor to ensure the continuous refinement and densification of the copper deposition layer grains. On the other hand, while providing rapid nucleation sites, the accelerator and the inhibitor molecules participate in the construction of a selectively permeable cathode interface adsorption layer through electrostatic or hydrogen bonding. The wetting agent provides additional active interface modification and ion transport channels. The three work synergistically to improve the tensile strength, elongation and surface smoothness of the composite copper foil.

[0017] Preferably, in step S1, the accelerator comprises polyoxyethylene alkylamine sulfonate.

[0018] Preferably, in step S1, the inhibitor comprises an aliphatic polyoxyethylene ether sulfonate.

[0019] Preferably, in step S1, the average sheet diameter of the graphene oxide is 1 μm.

[0020] This invention controls the average sheet diameter of graphene oxide within the above-mentioned range, which ensures the mechanical transfer efficiency of the reinforcing phase and avoids stress concentration caused by large-diameter graphene sheets.

[0021] In a preferred embodiment of the method for preparing the negative electrode current collector according to the present invention, in step S1, the concentration of the accelerator in the electrolyte is 10 mg / L-30 mg / L, the concentration of the inhibitor is 20 mg / L-50 mg / L, and the concentration of the graphene oxide dispersion is 10 mg / L-30 mg / L.

[0022] Preferably, in step S1, the concentration of the accelerator in the electrolyte is 20 mg / L, the concentration of the inhibitor is 50 mg / L, and the concentration of the graphene oxide dispersion is 10 mg / L.

[0023] In a preferred embodiment of the method for preparing the negative electrode current collector according to the present invention, in step S2, the process parameters of the pulse electrodeposition are: forward pulse current density 50 A / dm². 2 -60A / dm 2 Reverse pulse current density 10A / dm 2 -30A / dm 2 Forward conduction time is 50ms-100ms, reverse conduction time is 5ms-10ms, and pulse frequency is 50Hz-150Hz.

[0024] This invention limits the process parameters of the pulse electrodeposition to the above range, which can optimize the dynamic balance of "deposition-dissolution" of copper ions on the cathode surface, and at the same time create a suitable anchor point generation rate and embedding window time for the stepwise embedding of graphene, achieving a synergistic and excellent effect of mechanical properties and embedding uniformity.

[0025] Preferably, in step S2, the process parameters for pulse electrodeposition are: forward pulse current density 60 A / dm³. 2 Reverse pulse current density 30A / dm 2 The forward conduction time is 60ms, the reverse conduction time is 10ms, and the pulse frequency is 100Hz.

[0026] In a preferred embodiment of the method for preparing the negative electrode current collector according to the present invention, in step S2, the electrodeposition temperature is 40℃-55℃.

[0027] Preferably, in step S2, the electrodeposition temperature is 50°C.

[0028] In a preferred embodiment of the preparation method of the negative electrode current collector of the present invention, in step S2, the graphene oxide dispersion is added stepwise during the reverse pulse phase to a total concentration of 60 mg / L-100 mg / L, and the addition frequency is once every 10-30 pulse cycles.

[0029] Preferably, in step S2, the graphene oxide dispersion is added stepwise during the reverse pulse phase to a total concentration of 80 mg / L, with an addition frequency of once every 20 pulse cycles.

[0030] In a preferred embodiment of the method for preparing the negative electrode current collector according to the present invention, in step S2, the thickness of the composite copper foil is 4μm-8μm.

[0031] Preferably, in step S2, the thickness of the composite copper foil is 6 μm.

[0032] Secondly, the present invention provides a negative electrode current collector prepared by the preparation method described above.

[0033] Thirdly, the present invention provides the application of the negative electrode current collector in semi-solid-state batteries or solid-state batteries.

[0034] Compared with existing technologies, the beneficial effects of this invention are as follows: First, by employing a composite additive system containing sodium thiazolinyl dithiopropane sulfonate and / or thiazoline-2-thione, and combining it with a forward / reverse pulse alternating electrodeposition process, especially the stepwise addition of graphene oxide dispersion during the reverse pulse stage, this invention successfully achieves monodisperse, highly oriented, and uniform embedding of graphene oxide in a copper matrix, avoiding the stress concentration problem caused by graphene oxide agglomeration in traditional methods. Second, the negative electrode current collector prepared by this invention possesses ultra-high tensile strength, high elongation, and moderate surface roughness, simultaneously solving the technical bottleneck of traditional copper foil's difficulty in simultaneously achieving "high strength, high elongation, and high interfacial adhesion," fully meeting the manufacturing and service requirements of semi-solid and solid-state batteries under high pressure. Furthermore, the negative electrode current collector prepared by this invention exhibits excellent resistance to hydrofluoric acid corrosion. This is attributed to the dense copper deposition layer structure with low internal stress and the physical barrier effect of uniformly dispersed graphene oxide on the corrosive medium, providing crucial assurance for the interface stability and safety of semi-solid / solid batteries under high pressure and long-cycle conditions. In addition, the preparation method of this invention has a wide process window, good compatibility with existing electroplating production lines, and is easy to scale up for continuous production. Attached Figure Description

[0035] Figure 1 This is the Raman spectrum of graphene oxide in the composite copper foil of Example 1 of the present invention; Figure 2 The images shown are scanning electron microscope (SEM) images of the composite copper foil in Embodiment 1 of the present invention; (a) SEM image of the smooth surface of the composite copper foil; (b) SEM image of the rough surface of the composite copper foil. Detailed Implementation

[0036] To better illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described below with reference to specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0037] The following description, in conjunction with specific embodiments, illustrates the practical effects of the present invention.

[0038] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, equipment, etc. used are all commercially available unless otherwise specified.

[0039] The raw materials used in the following embodiments and comparative examples are described below, but are not limited to these materials: Polyoxyethylene alkylamine sulfonate was purchased from Wuhan Jihechang New Materials Co., Ltd. The graphene oxide dispersion with an average sheet diameter of 1 μm is produced by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., model number XF002-27440-44-0.

[0040] Example 1: This embodiment provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: polyoxyethylene alkylamine sulfonate (JPS) 20 mg / L, aliphatic polyoxyethylene ether sulfonate 50 mg / L, sodium thiazolinyl dithiopropane sulfonate (SH110) 10 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0041] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 30 A / dm 2 Forward conduction time ( t on 60ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0042] Raman spectroscopy was used to characterize the dispersion and structural integrity of graphene oxide in the above-mentioned composite copper foil, such as... Figure 1 As shown, the Raman spectrum contains two characteristic peaks of graphene: the D peak (1350 cm⁻¹). -1 ) and G peak (1580cm) -1 The D peak reflects lattice carbon defects, and the G peak reflects the degree of carbonization of the material. By calculating the ratio of the integral areas of the two peaks, the ID / IG ratio is approximately 1.20. The larger the ratio, the more crystal defects there are. The product contains graphene oxide with medium to high density defects, which on the one hand helps to enhance the interfacial bonding between graphene and the copper matrix, and on the other hand can provide more active channels for the transport of lithium ions during the subsequent battery charging and discharging process. Scanning electron microscopy was used to characterize the microstructure, dispersion state, and embedding structure of graphene oxide in the composite copper foil, such as... Figure 2 As shown, no obvious layer stacking or agglomerates were observed in the composite copper foil. Furthermore, the embedded structure in this embodiment not only ensures the consistency of the overall structure of the composite copper foil, but also allows the graphene oxide sheets to play a mechanical reinforcing role in the thickness direction, effectively improving the bending fatigue resistance of the current collector and the interfacial stability between it and the negative electrode active material layer. This endows the composite copper foil with the comprehensive advantages of conductivity, mechanical flexibility and interfacial compatibility, meeting the high-performance requirements of the negative electrode current collector for semi-solid / solid batteries.

[0043] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0044] Example 2: This embodiment provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: thiourea propyl sulfate (UPS) 20 mg / L, collagen 50 mg / L, thiazolidin-2-thione (H1) 30 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0045] (2) Pulse electrodeposition for the preparation of composite copper foil The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 30 A / dm 2 Forward conduction time ( t on 100ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0046] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0047] Example 3: This embodiment provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: thiourea propyl sulfate (UPS) 20 mg / L, collagen 50 mg / L, sodium thiazolinyl dithiopropane sulfonate (SH110) 30 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0048] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 10 A / dm 2 Forward conduction time ( t on 100ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0049] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0050] Comparative Example 1: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: polyoxyethylene alkylamine sulfonate (JPS) 20 mg / L, aliphatic polyoxyethylene ether sulfonate 50 mg / L, sodium thiazolinyl dithiopropane sulfonate (SH110) 10 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0051] (2) Preparation of composite copper foil by DC electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed using a titanium-plated iridium anode and cathode roller under direct current. The current density of the direct current power supply was 60 A / dm³. 2 A graphene oxide dispersion with an average sheet diameter of 1 μm was added in one go using a metering pump to a total concentration of 80 mg / L, so that the graphene oxide was embedded in a monodisperse or few-layer state, and finally a 6 μm composite copper foil containing copper and graphene oxide was deposited on the cathode.

[0052] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0053] Comparative Example 2: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: polyoxyethylene alkylamine sulfonate (JPS) 20 mg / L, aliphatic polyoxyethylene ether sulfonate 50 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0054] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 30 A / dm 2 Forward conduction time ( t on 60ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0055] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0056] Comparative Example 3: This comparative example provides a negative electrode current collector (copper foil) for solid-state batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: 50 mg / L of aliphatic polyoxyethylene ether sulfonate and 10 mg / L of sodium thiazolinyl dithiopropane sulfonate (SH110).

[0057] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 30 A / dm 2 Forward conduction time ( t on 60ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0058] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0059] Comparative Example 4: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: polyoxyethylene alkylamine sulfonate (JPS) 20 mg / L, sodium thiazolinyl dithiopropane sulfonate (SH110) 10 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0060] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 30 A / dm 2 Forward conduction time ( t on 60ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0061] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0062] Comparative Example 5: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: polyoxyethylene alkylamine sulfonate (JPS) 20 mg / L, aliphatic polyoxyethylene ether sulfonate 50 mg / L, and sodium thiazolinyl dithiopropane sulfonate (SH110) 10 mg / L.

[0063] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 30 A / dm 2 Forward conduction time ( t on 60ms, reverse conduction time ( t off10ms, pulse frequency 100Hz; Finally, a 6μm copper foil was deposited on the cathode.

[0064] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0065] Comparative Example 6: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: thiourea propyl sulfate (UPS) 20 mg / L, collagen 50 mg / L, and thiazolidin-2-thione (H1) 30 mg / L.

[0066] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 30 A / dm 2 Forward conduction time ( t on 60ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; Finally, a 6μm copper foil was deposited on the cathode.

[0067] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0068] Comparative Example 7: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: thiourea propyl sulfate (UPS) 20 mg / L, aliphatic polyoxyethylene ether sulfonate 50 mg / L, and thiazolidin-2-thione (H1) 30 mg / L.

[0069] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 10 A / dm 2 Forward conduction time ( t on 100ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; Finally, a 6μm copper foil was deposited on the cathode.

[0070] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0071] Comparative Example 8: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: polyoxyethylene alkylamine sulfonate (JPS) 20 mg / L, aliphatic polyoxyethylene ether sulfonate 50 mg / L, sodium thiazolinyl dithiopropane sulfonate (SH110) 10 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0072] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 40 A / dm² 2 Reverse pulse current density 30 A / dm 2 Forward conduction time ( t on100ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0073] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0074] Comparative Example 9: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: polyoxyethylene alkylamine sulfonate (JPS) 20 mg / L, aliphatic polyoxyethylene ether sulfonate 50 mg / L, sodium thiazolinyl dithiopropane sulfonate (SH110) 10 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0075] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 40 A / dm² 2 Reverse pulse current density 1 A / dm 2 Forward conduction time ( t on 60ms, reverse conduction time ( t off 10ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0076] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0077] Comparative Example 10: This comparative example provides a negative electrode current collector (copper foil) for semi-solid / solid batteries, the preparation method of which includes the following steps: (1) Preparation of electrolyte The basic electrolyte is prepared by: copper ions (Cu) 2+ 90g / L of sulfuric acid (H2SO4), 120g / L of chloride ions (Cl⁻), and 20mg / L of chloride ions (Cl⁻). Then, a composite additive was added to the above-mentioned basic electrolyte. The components and concentrations are as follows: polyoxyethylene alkylamine sulfonate (JPS) 20 mg / L, aliphatic polyoxyethylene ether sulfonate 50 mg / L, sodium thiazolinyl dithiopropane sulfonate (SH110) 10 mg / L, and graphene oxide dispersion with an average sheet diameter of 1 μm 20 mg / L.

[0078] (2) Preparation of composite copper foil by pulse electrodeposition The prepared electrolyte was heated to 50°C, and electrodeposition was performed under pulsed current using a titanium-plated iridium anode and cathode roller. The pulse parameters are set as follows: positive pulse current density 60 A / dm² 2 Reverse pulse current density 1 A / dm 2 Forward conduction time ( t on 65ms, reverse conduction time ( t off 5ms, pulse frequency 100Hz; During the pulse electrodeposition process, the periodic switching of the pulse power supply is used to add a quantitative amount of graphene oxide dispersion with an average sheet diameter of 1 μm through a metering pump during the reverse pulse phase. The addition frequency is once every 20 pulse cycles until the total concentration is 80 mg / L, so that the graphene oxide is embedded in a monodisperse or few-layer state. Finally, a 6 μm composite copper foil containing copper and graphene oxide is deposited on the cathode.

[0079] (3) Post-processing The deposited composite copper foil is sequentially passivated and anti-oxidation treated, washed with water, dried, and finally wound up to obtain the finished copper foil, which is the negative electrode current collector.

[0080] Test example: This test case presents the following performance tests on the negative electrode current collector (finished composite copper foil) of the embodiment and the comparative example.

[0081] (1) Tensile strength test Test method: The test was conducted using a universal tensile testing machine in accordance with the international standard IPC-TM-650-2.4.18.

[0082] (2) Elongation test Test method: The test was conducted using a universal tensile testing machine in accordance with the international standard IPC-TM-650-2.4.18.

[0083] (3) Surface roughness (Rz) test Test method: The test was conducted using the laser confocal method according to the IPC-TM-650-2.2.17 international standard.

[0084] (4) Elastic modulus test Test method: The test was conducted using an elastic modulus tester in accordance with the GB / T 3354-2018 standard.

[0085] (5) Peel strength test Test method: The test was conducted using an electrode peel strength tester in accordance with GB / T 2792-2014 standard.

[0086] (6) Hydrofluoric acid resistance test Test method: The copper foil was completely immersed in a 1% hydrofluoric acid (HF) solution and left to stand at room temperature (25±2)℃ for 48 hours. The surface color change, presence of corrosive spots, discolored areas or oxide layer peeling and other appearance characteristics were observed and recorded.

[0087] The table shows the performance test results of the negative electrode current collectors in the embodiments and comparative examples of the present invention. As shown in the table, this invention successfully prepared a high-performance graphene / copper composite negative electrode current collector for solid-state batteries through the synergistic design of pulsed electrodeposition technology and composite additive system, combined with a stepwise graphene embedding method. Specifically, this invention employs reverse pulsed electrodeposition, and in each reverse pulse stage, a quantitative graphene dispersion is added (once every 20 pulse cycles), achieving uniform embedding of graphene in a monodisperse or few-layer state in the copper matrix. This avoids the agglomeration problem in traditional co-deposition, thereby significantly improving the mechanical properties (tensile strength up to 735 MPa) and corrosion resistance (resistance to hydrofluoric acid without discoloration) of the composite foil. Secondly, the composite additive of this invention adopts a ternary synergistic mechanism of "accelerator + inhibitor + wetting agent," wherein JPS + fatty acid... The combination of polyoxyethylene ether sulfonate and SH110 exhibits the best overall performance, achieving a balance between high strength, high peel strength, and good ductility. The combination of UPS, collagen, and H1 offers advantages in surface smoothness and elongation. Furthermore, compared to traditional copper foil (tensile strength <400MPa, elongation <5%), the negative electrode current collector of this invention achieves simultaneous improvements in multiple key indicators such as tensile strength, elongation, elastic modulus, peel strength, and corrosion resistance, overcoming the technical bottleneck of achieving a balance between high strength, high elongation, and high corrosion resistance.

[0088] In summary, the negative electrode current collector (composite copper foil) prepared by this invention has excellent mechanical support, bonding strength with the negative electrode active material (high peel strength), and chemical stability (resistant to HF corrosion). It is particularly suitable for solid-state battery systems with stringent requirements for interface stability and is expected to significantly improve the cycle life and safety of semi-solid and solid-state batteries.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a negative electrode current collector, characterized in that, Includes the following steps: S1. Prepare the electrolyte; The electrolyte includes copper ions, sulfuric acid, chloride ions, and composite additives; The composite additive includes an accelerator, an inhibitor, a wetting agent, and a graphene oxide dispersion; The wetting agent includes sodium thiazolinyl dithiopropane sulfonate and / or thiazolin-2-thione; and in the electrolyte, the concentration of the wetting agent is 10 mg / L-30 mg / L; S2. Using a pulse electrodeposition process with alternating forward and reverse pulses, the electrolyte is pulse-deposited on the cathode. During the reverse pulse phase, graphene oxide dispersion is added to the electrolyte stepwise to embed the graphene oxide into the copper deposition layer, thereby obtaining a composite copper foil. S3. The composite copper foil is passivated and subjected to anti-oxidation treatment, washed, dried and wound up to obtain a negative electrode current collector.

2. The method for preparing the negative electrode current collector as described in claim 1, characterized in that, In step S1, the concentration of copper ions in the electrolyte is 80 g / L-120 g / L, the concentration of sulfuric acid is 80 g / L-120 g / L, and the concentration of chloride ions is 20 mg / L-40 mg / L.

3. The method for preparing the negative electrode current collector as described in claim 1, characterized in that, In step S1, the accelerator includes at least one of polydithiodipropanesulfonic acid, sodium 3-mercapto-1-propanesulfonate, sodium N,N-dimethyl-dithiocarbonylpropanesulfonate, thiourea propyl sulfate, sodium N-(3-sulfopropyl)-saccharin, and polyoxyethylene alkylamine sulfonate; the inhibitor includes at least one of collagen, gelatin, bone glue, and aliphatic polyoxyethylene ether sulfonate; the graphene oxide dispersion is a dispersed graphene oxide dispersion; and the average sheet diameter of the graphene oxide is 0.5 μm-2 μm.

4. The method for preparing the negative electrode current collector as described in claim 1, characterized in that, In step S1, the concentration of the accelerator in the electrolyte is 10 mg / L-30 mg / L, the concentration of the inhibitor is 20 mg / L-50 mg / L, and the concentration of the graphene oxide dispersion is 10 mg / L-30 mg / L.

5. The method for preparing the negative electrode current collector as described in claim 1, characterized in that, In step S2, the process parameters for pulse electrodeposition are: forward pulse current density 50 A / dm³. 2 -60A / dm 2 Reverse pulse current density 10A / dm 2 -30A / dm 2 Forward conduction time is 50ms-100ms, reverse conduction time is 5ms-10ms, and pulse frequency is 50Hz-150Hz.

6. The method for preparing the negative electrode current collector as described in claim 1, characterized in that, In step S2, the temperature of the pulse electrodeposition is 40℃-55℃.

7. The method for preparing the negative electrode current collector as described in claim 1, characterized in that, In step S2, the graphene oxide dispersion is added stepwise during the reverse pulse phase to a total concentration of 60 mg / L-100 mg / L, with an addition frequency of once every 10-30 pulse cycles.

8. The method for preparing the negative electrode current collector as described in claim 1, characterized in that, In step S2, the thickness of the composite copper foil is 4μm-8μm.

9. The negative electrode current collector prepared by any one of the preparation methods according to claims 1-8.

10. The application of the negative electrode current collector according to claim 9 in a semi-solid-state battery or a solid-state battery.

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