Method for preparing composite negative current collector of metal battery and application thereof

Abstract

The application belongs to the technical field of metal batteries, and provides a preparation method of a composite negative electrode current collector of a metal battery and application thereof. Pulse high-temperature Joule heat technology is used to deposit metal sources on the negative electrode current collector and in-situ alloying, to construct affinity alloy sites, reduce the heterogeneous nucleation energy barrier of the metal negative electrode, and induce uniform deposition, thereby effectively improving the cycle stability of the metal battery. Especially, the preparation of the lithium ion battery negative electrode current collector in-situ constructs lithium affinity alloy on the surface of the copper foil. The metal source is prepared into a sheet and stacked with the copper foil, and then pulse high-temperature Joule heat is performed. The application does not need expensive equipment or processing steps, greatly shortens the preparation time, reduces the heating temperature, and can also be applied to various metal battery negative electrode current collectors, and has the potential for industrialized mass production.

Description

Technical Field

[0001] This invention belongs to the field of metal battery technology, specifically relating to a method for preparing a composite negative electrode current collector for metal batteries and its application. Background Technology

[0002] The new era of high-quality, intelligent lifestyles is driving lithium-ion batteries towards "higher power, higher safety, higher energy density, and longer cycle life"—the "three highs and one long." Currently, the graphite anode commonly used in commercial lithium-ion batteries (LIBs) has reached near its theoretical specific capacity of 372 mAh / g, which is insufficient for high-energy-density batteries. In contrast, lithium metal battery (LMB) anodes possess extremely high theoretical specific capacity (3860 mAh / g), significantly improving the energy density of LMBs.

[0003] However, lithium metal anodes suffer from poor electrochemical stability and large electrode volume expansion, which easily leads to severe side reactions and dendrite growth, causing rapid capacity decay and even internal short circuits and thermal runaway. Therefore, improving the cycle performance and overall safety of lithium metal batteries (LMBs) has become an important research direction, especially focusing on the influence of current collectors, such as copper foil, on lithium nucleation / growth, local current density, and Li... + Flux distribution has a significant impact. Given the mature fabrication process and excellent structural stability of copper foil, surface functionalization of copper current collectors is considered the most commercially promising approach.

[0004] Surface functionalization of copper current collectors mainly involves atomic-level modification of copper foil, novel structural design, modification of lithiophilic sites, and construction of interfacial protective layers. This, in turn, modulates the intrinsic properties of the current collector and the distribution of its surface electric / ionic fields, inducing uniform lithium nucleation and deposition. Constructing lithiophilic alloy sites on the copper foil surface can reduce the lithium nucleation overpotential and promote uniform lithium nucleation and deposition. Therefore, utilizing pulsed high-temperature Joule heating technology to deposit lithiophilic metal sources onto copper current collectors and then alloying them in situ provides a simple and efficient method to achieve promising dendrite-free lithium metal anodes.

[0005] Furthermore, by analogy with the working principle of the composite negative electrode current collector in lithium metal batteries, and based on the change in the heterogeneous nucleation energy barrier of the negative electrode of the metal battery after the metal source and the current collector are alloyed, this invention can be extended to metal batteries such as sodium, potassium, magnesium, aluminum, zinc, and iron. Summary of the Invention

[0006] The purpose of this invention is to address the significant lattice mismatch between commercial current collectors and lithium metal anodes, leading to severe lithium-phobicity issues. This invention utilizes pulsed high-temperature Joule heating technology to deposit a lithium-philic metal source onto a copper current collector and alloy it in situ, constructing lithium-philic alloy sites, thereby effectively improving the performance of lithium metal batteries.

[0007] To overcome the problems existing in the background technology, the present invention provides a method for preparing a composite negative electrode current collector for metal batteries. The technical solution adopted is as follows:

[0008] (1) Take the purchased commercial negative electrode current collector metal foil, cut it into pieces, clean it, and dry it;

[0009] (2) Fabricate the metal source material to be composited;

[0010] (3) The current collector and the metal source are stacked and loaded in the heating zone of the conductive carrier of the Joule heating device;

[0011] (4) The atmosphere in the reaction chamber of the Joule heating equipment is regulated by using a vacuum pump and a gas cylinder;

[0012] (5) Start the power supply to perform high-temperature pulse Joule heating.

[0013] Regarding the selection of metal sources in this application: Priority is given to easily evaporable deposits that can be alloyed with the current collector; reducing the overpotential for nucleation at the negative electrode of the metal battery promotes uniform and dense deposition during metal discharge; the preferred metal source type is pure metal or metal compounds that do not produce negative effects during decomposition. For Joule heating, compared to the prolonged high temperatures of traditional tube furnaces, the collision energy between electrons and the crystal lattice is much higher than the thermal energy under the coupling effect of the electric and thermal fields, allowing alloying to occur at lower temperatures and significantly reducing heating space and operation time, thus lowering energy consumption and improving efficiency. Compared to other non-equilibrium heating methods such as laser ablation, plasma deposition, and microwaves, Joule heating equipment is simpler and more controllable. Regarding the selection of Joule heating power and time: ensuring that the current collector shape is not damaged and that the target metal is generated are the upper and lower limits; the experimental temperature is controlled by adjusting the operating voltage and current of the power supply.

[0014] Optionally, the current collector metal foil in step (1) is cleaned with one or more of hydrochloric acid, phosphoric acid, acetone, sodium oxalate, and ethanol to remove surface stains and oxide layers;

[0015] Optionally, the current collector cleaning method in step (1) includes rinsing and ultrasonic cleaning; optionally, the current collector drying method in step (1) includes vacuum drying and drying in an inert atmosphere. During and after cleaning, the metal foil should avoid prolonged contact with air and should be quickly transferred to a vacuum oven. It should be taken out after the vacuum oven cools to room temperature to avoid secondary oxidation.

[0016] The area of ​​the cut piece in step (1) must be smaller than that of the conductive carrier in step (3), and can be enlarged or reduced accordingly depending on the conductive carrier. A metal foil suitable for use as a negative electrode current collector must be selected, and its surface must be clean. Other factors have little impact on the finished product.

[0017] The sheet made in step (2) corresponds to the metal foil sheet in step (1), and its area must be smaller than that of the conductive carrier in step (3). The sheet should have a uniform distribution of internal materials, be dense, and free from contaminants causing side reactions. The addition of irrelevant substances such as binders and dispersants should be avoided as much as possible.

[0018] Optionally, the composite metal source material includes, but is not limited to, one or more of the following: metal foil, metal oxide, metal nitrate, metal halide, organometallic salt, organometallic framework, easily decomposable organometallic coordination polymer, metal hydroxide, metal hydroxy oxide, metal hydroxy carbonate, metal nitride, metal phosphide, metal sulfide, metal hydrosulfide, and metal cyanide.

[0019] Optionally, the sheet-like metal source material can be pressed into sheets by a hydraulic press, then spin-coated, scraped, or recrystallized onto a sheet-like carrier.

[0020] Optionally, the conductive carrier in the Joule heating zone can be a conductive metal, a conductive polymer, a graphene film, carbon cloth, carbon paper, carbon felt, etc., and the length of the conductive carrier can be 5 to 20 cm depending on the Joule heating equipment and the sample volume.

[0021] Optionally, the current collector and metal source can be introduced in a single-layer or multi-layer stacked manner. A single layer refers to one layer of current collector foil and one layer of metal source; multi-layer stacks must be aligned, and the total thickness should not be too great, otherwise it will be difficult to fix them in the conductive carrier. The current collector and metal source can consist of only one layer of conductive carrier. Setting up two layers serves two purposes: first, to fix the sample and prevent deformation, and second, to ensure more uniform heating from both sides.

[0022] Optionally, the Joule heating apparatus includes a built-in reaction chamber and an open reaction zone within a glove box. Optionally, the reaction zone is in a non-oxidizing atmosphere, including a low vacuum of 0.01–0.1 MPa, and a mixture of one or more gases selected from helium, argon, and nitrogen.

[0023] Optionally, the operating voltage applied during high-temperature pulsed heating is 10–50V, and the operating current is 0.5–20A; the temperature is raised to 100–900℃; the duration of a single pulse is 0.1–300s, and the number of pulses is unlimited. For example, 50–100 pulses are used for low-power applications, and 1–5 pulses are used for high-power applications, depending on the battery performance required for the specific application. Low-power applications use 5–30W to ensure alloy formation; high-power applications use 30–50W without damaging the material's shape.

[0024] Insufficient voltage will not achieve the required power output. Experimental results indicate that 50V is sufficient and does not need to be higher. Insufficient current will not achieve the required power output, while excessive current will deform the current collector foil, rendering it unusable. The metal source should be deposited at a temperature that prevents deformation of the current collector foil. Insufficient temperature will prevent thermal evaporation of the metal source, while excessive temperature will deform the current collector foil, rendering it unusable. The single pulse duration should be adjusted according to the actual power; insufficient duration will result in incomplete deposition, while excessive duration will lead to over-deposition, both affecting application.

[0025] Optionally, Joule heating high-temperature pulses include two methods: one-step high-temperature in-situ alloying of the metal source and current collector; and two-step methods: low-temperature long-term pulses of the metal source and current collector, followed by high-temperature rapid pulses to further alloy after removing excess metal source material. The one-step method is simple to operate, while the two-step method results in more uniform dispersion and more complete alloying. The temperature is determined by the alloy deformation time. Low-temperature Joule heating can be performed for a long time, while high-temperature Joule heating can only be performed for a short time to ensure that no shape change occurs. For copper-zinc alloys, temperatures below 200℃ are considered low-temperature, and temperatures of 250℃ and above are considered high-temperature. The low-temperature time is 1-10 minutes, and the high-temperature time is 0.5-5 seconds.

[0026] Optionally, the present invention can be extended to be applied to metal batteries such as lithium, sodium, potassium, magnesium, aluminum, zinc, and iron.

[0027] The in-situ preparation method of the composite negative electrode current collector for metal batteries described in this invention has the following advantages and guiding significance compared with the prior art:

[0028] By utilizing pulsed high-temperature Joule heating technology, rapid reactions are achieved between atoms under the coupling conditions of the electric and thermal fields of Joule heating. This rapid reaction, driven by kinetics and operating in a non-steady-state environment, significantly reduces preparation temperature and energy consumption, eliminating the need for expensive equipment or processing steps. This invention can be widely applied to the modification of current collectors in various metal batteries, providing a constructive method for metal surface modification. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Figure 1 The image shows the XRD pattern of the copper current collector after cleaning and drying in Example 1 of this invention.

[0031] Figure 2 This is the XRD pattern of the current collector after a Joule heating high-temperature pulse in Embodiment 1 of the present invention;

[0032] Figure 3 This is a SEM image of the copper current collector after cleaning and drying in Example 1 of the present invention;

[0033] Figure 4 This is a SEM image of the current collector after a Joule thermal pulse in Embodiment 1 of the present invention;

[0034] Figure 5 This is a diagram showing the cycle coulombic efficiency of a coin cell lithium copper battery assembled before and after Joule heating in Embodiment 1 of the present invention.

[0035] Figure 6 This is a morphology diagram of lithium deposition on a copper current collector after cleaning and drying, as shown in Example 1 of the present invention.

[0036] Figure 7 This is a morphology diagram of lithium deposited in the current collector after a Joule thermal pulse in Example 1 of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Embodiments of an in-situ preparation method for a composite negative electrode current collector for a metal battery according to the present invention have been specifically disclosed with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art.

[0039] The significant lattice mismatch between the copper current collector and the lithium metal anode commonly used in metal batteries leads to lithium apathy, affecting lithium metal deposition during discharge and consequently impacting battery performance. Joule heating is used to flow a high-frequency current through a conductive carrier, causing electrons to collide with the crystal lattice. These charged electrons transfer their energy to the lattice, increasing its vibrational frequency and generating heat, thus promoting lattice changes and alloy formation. Depositing other metals on the current collector surface and alloying them in situ creates a modification layer. This modification layer reduces the lithium nucleation overpotential or disperses the lithium into smaller nucleation sites, promoting uniform lithium nucleation and deposition, and improving the performance of the metal battery.

[0040] Specific Implementation Method 1: This implementation method, in conjunction with the accompanying drawings and technical solutions, is carried out according to the following steps:

[0041] (1) Take the copper current collector and cut it into round pieces with a diameter of 14-16 mm. Then clean it by ultrasonication in 0.1 M hydrochloric acid solution, acetone and ethanol in sequence. Dry it in a vacuum oven at 50℃ for 24 hours before use.

[0042] (2) Take zinc foil with a thickness of 0.1 mm and cut it into round pieces with a diameter of 16-19 mm for later use;

[0043] (3) Cut a 5cm long piece of carbon paper and hold it between the open Joule heating positive and negative electrodes in the glove box. Align the copper sheet and zinc sheet and place them on the carbon paper. Cover the top layer with another layer of carbon paper.

[0044] (4) The Joule thermoelectric electrode is placed in a glove box filled with high-purity argon gas, where the water and oxygen content is less than 0.1 ppm to avoid oxidation, because the negative electrode current collector is a conductive metal foil, such as copper foil, which cannot be used as a negative electrode current collector after oxidation.

[0045] (5) Start the power supply to perform high-temperature pulse Joule heating.

[0046] Specific Implementation Method Two: The difference between this implementation method and Specific Implementation Method One is that the 0.1mm thick zinc foil mentioned in step (2) is replaced with zinc nitrate or zinc acetate, which is pressed into discs of the corresponding size using a hydraulic press or dissolved in a solvent and spin-coated, scraped, and recrystallized onto carbon cloth for cutting. The other steps are the same as in Specific Implementation Method One.

[0047] Specific Implementation Method 3: The difference between this implementation method and Specific Implementation Method 1 or 2 is that the conductive carrier mentioned in step (3) is a graphene film, carbon cloth, carbon paper, carbon felt, etc. The other steps are the same as those in Specific Implementation Method 1 or 2.

[0048] Specific Implementation Method Four: The difference between this implementation method and Specific Implementation Methods One to Three is that 3 to 50 copper and zinc sheets are stacked sequentially and injected at once. Other steps are the same as those in Specific Implementation Methods One to Three.

[0049] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the top layer of carbon paper is removed, and a single layer of carbon paper is used for sample injection. The other steps are the same as in Specific Implementation Methods One to Four.

[0050] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One through Five in that it uses a built-in reaction chamber and utilizes a vacuum pump and gas cylinders to regulate the atmosphere inside the Joule heating device. The other steps are the same as in Specific Implementation Methods One through Five.

[0051] Specific Implementation Method Seven: The difference between this implementation method and Specific Implementation Methods One to Six is ​​that the atmosphere during the Joule heating high-temperature pulse is one or more mixed gases selected from helium, argon, and nitrogen. The other steps are the same as in Specific Implementation Methods One to Six.

[0052] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: after a single pulse, the zinc sheet is removed, the operating current is increased, and a higher temperature pulse is applied. The other steps are the same as in Specific Implementation Methods One to Seven.

[0053] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the metal source material is changed to gold, silver, platinum, magnesium, aluminum, tin, etc., for use in lithium metal batteries. The other steps are the same as in Specific Implementation Methods One to Eight.

[0054] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One through Nine in that the metal source material is changed to gold, tin, bismuth, nickel, silver, etc., for use in sodium metal batteries. The other steps are the same as in Specific Implementation Methods One through Nine.

[0055] Specific Implementation Method Eleven: This implementation method differs from Specific Implementation Methods One through Ten in that it repeats Specific Implementation Methods One through Nine 1 to 3 times. Other steps are the same as in Specific Implementation Methods One through Ten.

[0056] The present invention will now be described in detail with reference to the embodiments.

[0057] Example 1

[0058] A method for preparing a composite negative electrode current collector for a metal battery includes the following steps:

[0059] (1) Take the copper current collector and cut it into round pieces with a diameter of 14-16 mm. Then clean it by ultrasonication in 0.1 M hydrochloric acid solution, acetone and ethanol in sequence. Dry it in a vacuum oven at 50℃ for 24 hours before use.

[0060] (2) Take zinc foil with a thickness of 0.1 mm and cut it into round pieces with a diameter of 16-19 mm for later use;

[0061] (3) Cut a 5cm long piece of carbon paper and hold it between the open Joule heating positive and negative electrodes in the glove box. Align the copper sheet and zinc sheet and place them on the carbon paper. Cover the top layer with another layer of carbon paper.

[0062] (4) The Joule thermoelectric electrode was placed in a glove box filled with high-purity argon gas, where the water and oxygen content were both below 0.1 ppm.

[0063] (5) Start the Joule heating power supply to perform a single pulse for 5 to 120 seconds under the conditions of 50V and 10A.

[0064] The processed composite copper current collector is assembled into a lithium copper half-cell in the following order: positive electrode shell, composite copper current collector, electrolyte, separator, electrolyte, lithium metal negative electrode, gasket, spring, and negative electrode shell. The battery model is button cell 2032.

[0065] Electrochemical performance testing and characterization of lithium copper half-cells:

[0066] Press 0.5mAh cm -2 The capacity is 0.5 mA cm -2The surface current density was deposited on the surface of the composite copper current collector and subjected to cyclic testing; at 0.5 mA cm⁻¹ -2 After the surface current density was deposited on the surface of the composite copper current collector for 10 hours, the battery was disassembled, the negative electrode was cleaned with dimethyl carbonate (DMC) to remove lithium salts from the electrolyte, and then air-dried. The morphology of the deposited lithium was observed by SEM injection test using a vacuum transfer chamber.

[0067] from Figure 1 and Figure 2 Comparative observation reveals that a new copper-zinc alloy peak appears after the Joule thermal pulse, indicating that in-situ alloying has been achieved.

[0068] from Figure 3 and Figure 4 Comparative observation reveals that alloy particles of 10–100 nm appear on the surface of the Joule thermal pulse copper current collector.

[0069] from Figure 5 Comparative observations show that the electrochemical performance of the composite current collector after Joule thermal pulse is significantly improved, with the number of stable cycles increasing from about 100 to about 400.

[0070] from Figure 6 and Figure 7 Comparative observation reveals that the composite current collector after the Joule thermal pulse has a significant effect on inducing lithium deposition, and the deposited lithium changes from slender strips to dense large particles.

[0071] Example 2

[0072] Combining the steps in Embodiment 1 above,

[0073] (1) Take the copper current collector and cut it into round pieces with a diameter of 14-16 mm. Then clean it by ultrasonication in 0.1 M hydrochloric acid solution, acetone and ethanol in sequence. Dry it in a vacuum oven at 50℃ for 24 hours before use.

[0074] (2) Weigh 0.2g of zinc nitrate granules and spread them evenly in the tableting mold. Press them with a hydraulic press to 10Mpa and take out the tablet sample for later use.

[0075] (3) Cut a 5cm long piece of carbon paper and hold it between the open Joule heating positive and negative electrodes in the glove box. Align the copper sheet with the zinc source and place it on the carbon paper. Cover the top layer with another layer of carbon paper.

[0076] (4) The Joule thermoelectric electrode was placed in a glove box filled with high-purity argon gas, where the water and oxygen content were both below 0.1 ppm.

[0077] (5) Start the power supply and perform a single pulse for 5-120 seconds under the conditions of 50V and 10A.

[0078] The processed composite copper current collector is assembled into a lithium copper half-cell in the following order: positive electrode shell, composite copper current collector, electrolyte, separator, electrolyte, lithium metal negative electrode, gasket, spring, and negative electrode shell. The battery model is button cell 2032.

[0079] Example 3

[0080] Combining the steps in Embodiment 1 above,

[0081] (1) Take the copper current collector and cut it into round pieces with a diameter of 14-16 mm. Then clean it by ultrasonication in 0.1 M hydrochloric acid solution, acetone and ethanol in sequence. Dry it in a vacuum oven at 50℃ for 24 hours before use.

[0082] (2) Take zinc foil with a thickness of 0.1 mm and cut it into round pieces with a diameter of 16-19 mm for later use;

[0083] (3) Cut a 5cm long graphene film and clamp it between the open Joule heating positive and negative electrodes in the glove box. Place one or more copper and zinc sheets on the graphene film and cover the top layer with another graphene film to change the Joule heating pulse heating rate.

[0084] (4) The Joule thermoelectric electrode was placed in a glove box filled with high-purity argon gas, where the water and oxygen content were both below 0.1 ppm.

[0085] (5) Start the power supply and perform a single pulse for 5 to 120 seconds under the conditions of 50V and 0.5 to 10A.

[0086] The processed composite copper current collector is assembled into a lithium copper half-cell in the following order: positive electrode shell, composite copper current collector, electrolyte, separator, electrolyte, lithium metal negative electrode, gasket, spring, and negative electrode shell. The battery model is button cell 2032.

[0087] Example 4

[0088] Combining the steps in Embodiment 1 above,

[0089] (1) Take the copper current collector and cut it into round pieces with a diameter of 14-16 mm. Then clean it by ultrasonication in 0.1 M hydrochloric acid solution, acetone and ethanol in sequence. Dry it in a vacuum oven at 50℃ for 24 hours before use.

[0090] (2) Take zinc foil with a thickness of 0.1 mm and cut it into round pieces with a diameter of 16-19 mm for later use;

[0091] (3) Cut a 5cm long piece of carbon paper and hold it between the open Joule heating positive and negative electrodes in the glove box. Align the copper sheet and zinc sheet and place them on the carbon paper. Cover the top layer with another layer of carbon paper.

[0092] (4) The glove box is filled with high-purity argon gas, and the water and oxygen content is less than 0.1 ppm;

[0093] (5) Start the power supply and pulse for 5 seconds under working conditions of 50V and 10A. After removing the zinc sheet, pulse multiple times for 2 seconds under working conditions of 50V and 10-20A.

[0094] The processed composite copper current collector is assembled into a lithium copper half-cell in the following order: positive electrode shell, composite copper current collector, electrolyte, separator, electrolyte, lithium metal negative electrode, gasket, spring, and negative electrode shell. The battery model is button cell 2032.

[0095] Example 5

[0096] Combining the steps in Embodiment 1 above,

[0097] (1) Take the copper current collector and cut it into round pieces with a diameter of 14-16 mm. Then clean it by ultrasonication in 0.1 M hydrochloric acid solution, acetone and ethanol in sequence. Dry it in a vacuum oven at 50℃ for 24 hours before use.

[0098] (2) Take zinc foil with a thickness of 0.1 mm and cut it into round pieces with a diameter of 16-19 mm for later use;

[0099] (3) Cut a 5cm long piece of carbon paper and hold it between the positive and negative electrodes of the built-in reaction chamber. Align the copper sheet and zinc sheet and place them on the carbon paper. Cover the top layer with another layer of carbon paper.

[0100] (4) Use a vacuum pump and a gas cylinder to repeatedly pump and release nitrogen three times so that the Joule heating high-temperature pulse is carried out under flowing nitrogen conditions;

[0101] (5) Start the power supply and perform a single pulse for 5-120 seconds under the conditions of 50V and 5-10A.

[0102] The processed composite copper current collector is assembled into a lithium copper half-cell in the following order: positive electrode shell, composite copper current collector, electrolyte, separator, electrolyte, lithium metal negative electrode, gasket, spring, and negative electrode shell. The battery model is button cell 2032.

[0103] Example 6

[0104] Combining the steps in Embodiment 1 above,

[0105] (1) Take the copper current collector and cut it into round pieces with a diameter of 14-16 mm. Then clean it by ultrasonication in 0.1 M hydrochloric acid solution, acetone and ethanol in sequence. Dry it in a vacuum oven at 50℃ for 24 hours before use.

[0106] (2) Take a 0.2mm thick magnesium foil, sand it with sandpaper to remove the surface oxide layer, clean and dry it, and cut it into round pieces with a diameter of 16-19mm for later use;

[0107] (3) Cut a 5cm long piece of carbon paper and hold it between the open Joule heating positive and negative electrodes in the glove box. Align the copper sheet and magnesium sheet and place them on the carbon paper. Cover the top layer with another layer of carbon paper.

[0108] (4) The Joule thermoelectric electrode was placed in a glove box filled with high-purity argon gas, where the water and oxygen content were both below 0.1 ppm.

[0109] (5) Start the power supply and perform a single pulse for 5 to 120 seconds under the conditions of 50V and 0.5 to 10A.

[0110] The processed composite copper current collector is assembled into a lithium copper half-cell in the following order: positive electrode shell, composite copper current collector, electrolyte, separator, electrolyte, lithium metal negative electrode, gasket, spring, and negative electrode shell. The battery model is button cell 2032.

[0111] Example 7

[0112] Combining the steps in Embodiment 1 above,

[0113] (1) Take the copper current collector and cut it into round pieces with a diameter of 14-16 mm. Then clean it by ultrasonication in 0.1 M hydrochloric acid solution, acetone and ethanol in sequence. Dry it in a vacuum oven at 50℃ for 24 hours before use.

[0114] (2) Take a 0.1 mm thick silver foil, clean and dry it with anhydrous ethanol, and cut it into round pieces with a diameter of 16-19 mm for later use.

[0115] (3) Cut a 5cm long piece of carbon paper and hold it between the open Joule heating positive and negative electrodes in the glove box. Align the copper sheet and silver sheet and place them on the carbon paper. Cover the top layer with another layer of carbon paper.

[0116] (4) The Joule thermoelectric electrode was placed in a glove box filled with high-purity argon gas, where the water and oxygen content were both below 0.1 ppm.

[0117] (5) Start the power supply and perform a single pulse for 5 to 120 seconds under the conditions of 50V and 0.5 to 10A.

[0118] The processed composite copper current collector is assembled into a sodium-copper half-cell in the following order: positive electrode shell, composite copper current collector, electrolyte, separator, electrolyte, sodium metal negative electrode, gasket, spring, and negative electrode shell. The cell model is button cell 2032.

[0119] Press 0.5mAh cm -2 The capacity is 0.5 mA cm -2 The surface current density was deposited on the surface of the composite copper current collector and subjected to cyclic testing. The affinity of the composite copper current collector for sodium was determined based on the discharge curve of sodium metal on the composite copper current collector.

[0120] This composite current collector can be applied to metal batteries such as potassium, magnesium, aluminum, zinc, and iron.

[0121] In summary, this invention provides a novel method for in-situ preparation of composite negative electrode current collectors. By superimposing the current collector and the metal source material into the sample, the Joule heating effect is used to generate instantaneous high temperature, allowing the metal source material to be rapidly reconstructed and alloyed in-situ with the current collector. This method has the potential for large-scale mass production and application.

[0122] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a composite negative electrode current collector for a metal battery, characterized in that, Includes the following steps: (1) Cut the copper foil, which will be used as the negative electrode current collector, into pieces, clean and dry them; (2) The metal source material is made into a sheet, wherein the metal source material is a zinc source material, a magnesium source material or a silver source material; (3) The copper foil and the metal source material are stacked and loaded into the heating zone of the conductive carrier of the Joule heating device; (4) Use a vacuum pump or gas cylinder to regulate the reaction chamber of the Joule heating device to a non-oxidizing atmosphere; (5) Start the power supply to perform high-temperature pulse Joule heating, so that the metal source material is deposited on the surface of the copper foil and alloyed with the copper foil in situ to obtain a composite negative electrode current collector.

2. The method for preparing the composite negative electrode current collector of the metal battery according to claim 1, characterized in that, In step (1), the copper foil is ultrasonically cleaned and rinsed with one or more of hydrochloric acid, phosphoric acid, acetone, sodium oxalate, and ethanol to remove surface stains and oxide layers, while avoiding secondary oxidation.

3. The method for preparing the composite negative electrode current collector of the metal battery according to claim 1, characterized in that, The zinc source material is zinc foil, zinc nitrate, or zinc acetate; the magnesium source material is magnesium foil; and the silver source material is silver foil.

4. The method for preparing the composite negative electrode current collector of the metal battery according to claim 1, characterized in that, In step (2), the non-sheet metal source material is pressed into sheets by a hydraulic press, then spin-coated, scraped, and recrystallized onto a sheet-like carrier.

5. The method for preparing the composite negative electrode current collector of the metal battery according to claim 1, characterized in that, In step (3), the copper foil and the metal source material are introduced by means of single-layer stacking or multi-layer stacking, and the metal source material is provided on at least one side of the copper foil.

6. The method for preparing the composite negative electrode current collector of the metal battery according to claim 1, characterized in that, The conductive carrier in the heating zone in step (3) is one or more of the following: conductive metal, conductive polymer, graphene film, carbon cloth, carbon paper, and carbon felt.

7. The method for preparing the composite negative electrode current collector of the metal battery according to claim 1, characterized in that, In step (5), the working voltage applied during high-temperature pulse is 10-50V, the working current is 0.5-20A, the temperature is raised to 100-900℃, the single pulse time is 0.1-300s, and the number of pulses is unlimited.

8. The method for preparing the composite negative electrode current collector of the metal battery according to claim 1, characterized in that, In step (4), the reaction zone is in a non-oxidizing atmosphere, including a mixture of one or more gases such as helium, argon, and nitrogen, as well as a low vacuum.

9. The method for preparing the composite negative electrode current collector of the metal battery according to claim 1, characterized in that, In step (5), the Joule heating high-temperature pulse is used to perform one-step high-temperature in-situ alloying of the metal source and the current collector, or the metal source and the current collector are first subjected to low-temperature long-term pulses to remove excess metal source, and then further alloyed by high-temperature rapid pulses.

10. The application of the composite negative electrode current collector obtained by any one of claims 1 to 9 in lithium, sodium, potassium, magnesium, aluminum, zinc, and iron metal batteries.

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