Copper current collector and use thereof

Abstract

The present application provides a copper current collector and a use thereof. The copper current collector comprises a substrate layer and a copper layer arranged on at least one side of the substrate layer; and the relative texture coefficient (RTC) of all grains in the copper layer along a (111) crystal plane orientation satisfies: 20%≤RTC≤50%.

Description

A copper current collector and its application Technical Field

[0001] This application belongs to the field of lithium-ion battery technology, specifically relating to a copper current collector and its application. Background Technology

[0002] Commercial copper foil is a common negative electrode current collector in industry. Its "lithium-repellent" properties are detrimental to the uniform distribution of lithium ions, severely affecting the nucleation and subsequent growth of metallic lithium, and easily causing problems such as lithium dendrite growth, local short circuits, and electrode failure. Therefore, how to improve the uniform deposition of lithium on the surface of copper foil to further optimize battery performance has become one of the main issues in optimizing copper current collectors.

[0003] In recent years, matching lithium metal anodes with ultra-high theoretical specific capacity (3860 mAh / g) to lithium batteries has been considered one of the effective ways to achieve a new generation of high-energy-density rechargeable batteries. Currently, many lithium metal full batteries often adopt a high N / P ratio (N / P > 10) strategy to obtain better full-cell cycle stability, but this undoubtedly seriously reduces the actual energy density of the lithium metal anode (<351 mAh / g vs. graphite: 372 mAh / g), failing to improve the overall battery energy density. In contrast, anode-free design is the most ideal high-energy-density lithium metal full-cell construction scheme. Anode-free lithium metal batteries eliminate the need for initial anode active materials, pushing the overall battery energy density to its limit, exceeding 450 Wh / kg. -1 It is considered the ultimate choice for high-energy-density lithium metal batteries.

[0004] However, for electrodeless lithium metal batteries, the lithium-repellent properties of traditional copper current collectors also lead to uneven deposition and stripping of lithium ions on the copper foil surface during charge-discharge cycles. This easily results in lithium dendrites and "dead lithium," causing poor cycle performance and limiting the large-scale application of electrodeless lithium metal batteries. Furthermore, the uneven deposition of lithium ions on the copper foil surface often results in a dendritic, porous structure with poor bonding to the current collector, leading to poor mechanical stability and electrochemical reversibility. This can also cause rapid battery failure and significant safety hazards.

[0005] Furthermore, due to the lack of protection from a stable host material on the negative electrode side or compensation from excess active lithium, the irreversible loss of lithium resources caused by the generation of "dead lithium" and side reactions between the electrolyte and metallic lithium during cycling will be directly reflected in the loss of battery capacity, thus affecting the battery's cycle life. Summary of the Invention

[0006] To address the problems and shortcomings of existing technologies, this application provides a copper current collector and its application. This copper current collector can achieve uniform deposition of lithium on the copper current collector, promote the formation of a stable inorganic enriched solid electrolyte interface (SEI), and thus effectively suppress the formation of lithium dendrites and "dead lithium" on the copper current collector, thereby improving the battery's cycle charge and discharge performance.

[0007] According to a first aspect of this application, a copper current collector is provided, comprising a substrate layer and a copper layer disposed on at least one side of the substrate layer; wherein the relative texture coefficients (RTCs) of the grains in the copper layer along the (111) crystal plane orientation all satisfy: 20% ≤ RTC ≤ 50%.

[0008] This application controls the relative texture coefficient (RTC) of the grains in the copper layer along the (111) crystal plane to satisfy: 20% ≤ RTC ≤ 50%. Because the copper (111) crystal plane has a low lattice matching degree with the lithium (100) crystal plane, reducing the orientation degree of the grains in the copper layer along the (111) crystal plane can promote the uniform deposition of lithium on the copper current collector during charge-discharge cycles. However, the relative texture coefficient (RTC) of the grains in the copper layer along the (111) crystal plane should not be too low. If it is too low, it will lead to low mechanical properties such as tensile strength of the copper current collector, affecting the processing performance of the copper current collector.

[0009] In some embodiments, the roughness range of the copper current collector is Ra≤80nm. If Ra is too high, it can easily lead to uneven lithium deposition, thereby deteriorating the charge-discharge cycle performance of the battery.

[0010] In some embodiments, one side of the substrate layer includes a copper layer and the other side includes an aluminum layer.

[0011] In some embodiments, the copper layer satisfies any one or more of the following conditions: (1) The thickness of the copper layer is not less than 100 nm; in some embodiments, the thickness of the copper layer is not less than 500 nm; if the copper layer is too thin, i.e. the conductive layer is too thin, it will result in poor conductivity, increase the cycle resistance, and be detrimental to the cycle performance of the negative electrode-free lithium metal battery; in some embodiments, the thickness of the copper layer is 500~2000 nm; the copper layer should not be too thick either. Although a thicker layer can improve conductivity, it will result in a thicker copper current collector, which is not conducive to improving the energy density of the battery; in some embodiments, the thickness of the copper layer is 800~1200 nm; furthermore, controlling the thickness of the copper layer within the above range can better balance the conductivity and energy density of the battery; (2) The copper content in the copper layer is not less than 80 wt%; in some embodiments, the copper content in the copper layer is not less than 99.5 wt%.

[0012] In some embodiments, the aluminum layer satisfies any one or more of the following conditions: (1) the thickness of the aluminum layer is not less than 100 nm; in some embodiments, the thickness of the aluminum layer is not less than 500 nm; in some embodiments, the thickness of the aluminum layer is 500~2000 nm; in some embodiments, the thickness of the aluminum is 800~1200 nm; (2) the aluminum content in the aluminum layer is not less than 80 wt%; in some embodiments, the aluminum content in the aluminum layer is not less than 99.5 wt%. Similar to the copper layer, the thickness and purity of the aluminum layer also need to be controlled within a certain range to take into account the conductivity and energy density of the battery.

[0013] In some embodiments, the copper layer satisfies any one or more of the following conditions: (1) the thickness of the substrate layer is 1~10μm; controlling the thickness of the polymer film within the above range can ensure that there is a certain thickness to support the copper layer and improve the mechanical strength of the copper current collector, while avoiding the effect of excessively thick polymer film on the energy density of the battery; (2) the substrate layer includes at least one of polymer film, organic fiber layer, carbon layer, inorganic material layer, and conductive particles; (3) the substrate layer includes a polymer film, the material of which includes one or more of polyethylene terephthalate, polypropylene, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene ether, polystyrene, and polyimide; or, the substrate layer includes conductive particles, the conductive particles including at least one of carbon material and metal material.

[0014] In some embodiments, according to the second aspect of this application, a method for preparing the above-mentioned copper current collector is provided, specifically as follows: using a polymer film as a base film, copper layers are deposited on both sides of the polymer film by magnetron sputtering; wherein, the magnetron sputtering current is 10~40A, the magnetron sputtering radio frequency is 13.56 MHz, the deposition time is 4~240s, the working pressure is not higher than 5Pa, and the inert gas flow rate is 20-300mL / min. By controlling the relevant process parameters of the above-mentioned magnetron sputtering process, especially by using a specific radio frequency power supply (AC power supply) and controlling specific sputtering power and deposition time, the copper layer grains formed on the polymer film can have a specific range of relative texture coefficient (RTC) along the (111) crystal plane orientation. That is, while ensuring the tensile strength of the copper current collector, it can promote the uniformity of lithium deposition and the stability of the formed SEI, effectively suppress the formation of lithium dendrites and "dead lithium", and improve the battery cycle charge and discharge performance. Furthermore, regarding sputtering power and deposition time, if the sputtering power is too low, the relative texture coefficient (RTC) of the copper layer grains oriented along the (111) crystal plane will be high; while if the sputtering power is too high, the energy during sputtering will be too high, which will easily break through the polymer film and form pore defects. If the deposition time is too short, the deposited copper layer will be too thin and the conductivity will be poor; if the deposition time is too long, the deposited copper layer will be too thick and the prepared copper current collector will be too heavy, resulting in a decrease in the energy density of the battery.

[0015] In some implementations, the inert gas includes argon.

[0016] According to a third aspect of this application, an application of a copper current collector in electrodeless lithium metal batteries is provided. For electrodeless lithium metal batteries, utilizing the copper current collector provided in this application can significantly optimize the electrochemical performance of electrodeless lithium metal batteries, demonstrating the adaptability of the copper current collector in electrodeless lithium metal batteries.

[0017] Electrodeless lithium metal batteries typically use a traditional copper current collector as the negative electrode, meaning only copper foil serves as the negative electrode. During charging, lithium ions combine with electrons on the surface of the copper current collector, resulting in lithium deposition and the formation of lithium metal. During discharging, the lithium metal on the surface of the copper current collector dissolves, reforming into lithium ions and electrons, which then return to the positive electrode, repeating this process. Because there is no conventional negative electrode active material like graphite to bind the lithium ions, a significant amount of lithium ions are consumed during charging and discharging in electrodeless lithium metal batteries. This is partly due to numerous side reactions between deposited lithium and the organic electrolyte during charging, and partly due to uneven deposition and dissolution of lithium ions and lithium metal during charging and discharging. Therefore, the biggest problem facing electrodeless lithium metal batteries is their poor charge-discharge cycle stability. Furthermore, because traditional electrodeless lithium metal batteries use only copper foil as the negative electrode, their poor mechanical stability also contributes to decreased charge-discharge cycle stability, leading to rapid battery failure and significant safety hazards.

[0018] The copper current collector with a specific microstructure provided in this application, through multiple micro- and macro-structural controls of the copper current collector, can significantly promote the uniform deposition of lithium on the copper current collector in anode-free lithium metal batteries. It can also promote the formation of a stable inorganic enriched solid electrolyte interface (SEI) at the anode interface, thereby effectively suppressing the formation of lithium dendrites and "dead lithium," and improving the cycle charge-discharge performance of anode-free lithium metal batteries. Moreover, using a polymer film as a support for the copper layer can effectively improve the mechanical properties of the copper current collector, enabling it to effectively withstand the cyclic stress during charge-discharge cycles and maintain a relatively stable state under long-term charge-discharge cycles, which is beneficial for further optimizing the cycle charge-discharge performance of anode-free lithium metal batteries.

[0019] According to a fourth aspect of this application, a copper current collector is provided for use in lithium-ion batteries, conductive elements, magnetic materials, or electromagnetic shielding products.

[0020] According to a fifth aspect of this application, an electrode is provided, comprising the copper current collector described above or the copper current collector prepared by the method described above.

[0021] According to a sixth aspect of this application, a negative electrode-free lithium metal battery is provided, which further includes a positive electrode comprising lithium iron phosphate positive electrode material. Using lithium iron phosphate positive electrode material as the positive electrode active material of the negative electrode-free lithium metal battery results in a negative electrode-free lithium metal battery with better cycle charge-discharge performance, which is more conducive to the realization of the electrochemical performance of the negative electrode-free lithium metal battery.

[0022] In some embodiments, the positive electrode also includes a conductive agent and a binder, and the mass ratio of lithium iron phosphate positive electrode material, conductive agent and binder is 94~98:1.5~3.5:1~2.5.

[0023] In some embodiments, the conductive agent includes one or more of conductive carbon black and carbon nanotubes; the binder includes one or more of polyvinylidene fluoride, polyacrylic acid, and polymethyl methacrylate.

[0024] In summary, the electrodeless lithium metal battery provided in this application uses a copper current collector with a specific structure as the negative electrode. The relative texture coefficient of the copper layer along the (111) crystal plane of this copper current collector satisfies the following condition: 20% ≤ RTC ≤ 50%. This ensures uniform deposition of lithium on the copper current collector and stable SEI formation during charge-discharge cycles, thus effectively improving the charge-discharge cycle stability of the battery, especially the electrodeless lithium metal battery. Furthermore, the use of a polymer film as a support layer for the copper layer in this copper current collector gives it good mechanical properties, which further enhances the cycle performance of the battery, especially the electrodeless lithium metal battery. Embodiments of the present invention

[0025] Example 1

[0026] 1. Preparation of copper current collectors

[0027] The copper current collector of this embodiment was prepared according to the following procedure:

[0028] A 4.5 μm thick biaxially oriented PET film (purchased from Yihua Toray, model 4.5D08, surface roughness 90 nm) was placed in a magnetron sputtering machine. The power supply was an RF power supply with a frequency of 13.56 MHz. A copper target (purity 99.99%) was used as the target material, the target current was 10 A, argon gas was used as the gas source, the gas flow rate was 60 mL / min, the gas pressure inside the chamber was 1 Pa, and the cooling temperature of the main roller was -30 °C. The two surfaces of the PET film were magnetron sputtered for 109 s respectively, thus preparing a copper layer with a thickness of 1000 nm on each of the two surfaces of the PET film, thereby obtaining a copper current collector with a thickness of 6.5 μm.

[0029] 2. Preparation of negative electrode-free lithium metal batteries

[0030] For the negative electrode: the copper current collector prepared above is used as the negative electrode;

[0031] For the positive electrode, the current collector is made of aluminum foil (12μm), the active material is lithium iron phosphate, and the active material layer includes lithium iron phosphate, conductive carbon black (Super P), carbon nanotubes, and polyvinylidene fluoride in a mass ratio of 96:1.6:0.7:1.7.

[0032] The electrolytes are lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium nitrate (LiNO3), with concentrations of 1 mol·L⁻¹ respectively. -12 wt.%, the electrolyte is 1,2-dimethoxymethane (DME) and 1,3-dioxolane (DOL) in a volume ratio of 1:1;

[0033] For the diaphragm, a polypropylene diaphragm (20 μm thick) is used.

[0034] Using the above materials, a negative electrode-free lithium metal battery was assembled according to the relevant process, with a battery capacity of 1Ah.

[0035] Example 2

[0036] 1. Preparation of copper current collectors

[0037] The procedure is basically the same as in Example 1, except that the target current is 20A and the processing time is 47s. The rest of the operation is the same as in Example 1.

[0038] 2. Preparation of negative electrode-free lithium metal batteries

[0039] The preparation of the negative electrode-free lithium metal battery in this embodiment is the same as in Example 1.

[0040] Example 3

[0041] 1. Preparation of copper current collectors

[0042] The procedure is basically the same as in Example 1, except that the target current is 30A and the processing time is 21s. The rest of the operation is the same as in Example 1.

[0043] 2. Preparation of negative electrode-free lithium metal batteries

[0044] The preparation of the negative electrode-free lithium metal battery in this embodiment is the same as in Example 1.

[0045] Example 4

[0046] 1. Preparation of copper current collectors

[0047] The procedure is basically the same as in Example 1, except that the target current is 40A and the processing time is 8s. The rest of the operation is the same as in Example 1.

[0048] 2. Preparation of negative electrode-free lithium metal batteries

[0049] The preparation of the negative electrode-free lithium metal battery in this embodiment is the same as in Example 1.

[0050] Example 5

[0051] 1. Preparation of copper current collectors

[0052] The process is basically the same as in Example 1, except that the copper layer thickness is 500 nm, and the processing time is controlled to be 54.5 s. The rest of the operations are the same as in Example 1.

[0053] 2. Preparation of negative electrode-free lithium metal batteries

[0054] The preparation of the negative electrode-free lithium metal battery in this embodiment is the same as in Example 1.

[0055] Example 6

[0056] 1. Preparation of copper current collectors

[0057] The process is basically the same as in Example 1, except that the copper layer thickness is 2000 nm, and the processing time is controlled to be 218 s. The rest of the operation is the same as in Example 1.

[0058] 2. Preparation of negative electrode-free lithium metal batteries

[0059] The preparation of the negative electrode-free lithium metal battery in this embodiment is the same as in Example 1.

[0060] Example 7

[0061] 1. Preparation of copper current collectors

[0062] The procedure is basically the same as in Example 1, except that the PET film is replaced with a PP film (purchased from Jiadeli, model 6014H). The rest of the operation is the same as in Example 1.

[0063] 2. Preparation of negative electrode-free lithium metal batteries

[0064] The preparation of the negative electrode-free lithium metal battery in this embodiment is the same as in Example 1.

[0065] Example 8

[0066] 1. Preparation of copper current collectors

[0067] The procedure is essentially the same as in Example 1, except that the PET film is replaced with a PPS film (purchased from Toray, model 4-1X00). All other operations are the same as in Example 1.

[0068] 2. Preparation of negative electrode-free lithium metal batteries

[0069] The preparation of the negative electrode-free lithium metal battery in this embodiment is the same as in Example 1.

[0070] Example 9

[0071] 1. Preparation of copper current collectors

[0072] The procedure is basically the same as in Example 1, except that the copper layer thickness is 400 nm and the processing time is 43.6 s. The rest of the operation is the same as in Example 1.

[0073] 2. Preparation of negative electrode-free lithium metal batteries

[0074] The preparation of the negative electrode-free lithium metal battery in this comparative example is the same as in Example 1.

[0075] Example 10

[0076] 1. Preparation of copper current collectors

[0077] The procedure is essentially the same as in Example 1, except that the PET film is replaced with a PET film with a surface roughness Ra of 110 nm. All other operations are the same as in Example 1.

[0078] 2. Preparation of negative electrode-free lithium metal batteries

[0079] The preparation of the negative electrode-free lithium metal battery in this comparative example is the same as in Example 1.

[0080] Comparative Example 1

[0081] In this comparative example, the copper current collector in Example 1 was replaced with a conventional 4.5μm copper foil.

[0082] Furthermore, the preparation of the lithium metal battery without a negative electrode in the comparative example is consistent with that in Example 1.

[0083] Comparative Example 2

[0084] 1. Preparation of copper current collectors

[0085] The copper current collector of this comparative example was prepared according to the following procedure:

[0086] A 4.5 μm thick biaxially oriented PET film (purchased from Yihua Toray, model 4.5D08) was placed in a magnetron sputtering machine. The power supply was DC, a copper target (99.99% purity) was used as the target material, the target current was 10A, argon was used as the gas source, the gas flow rate was 60 mL / min, the gas pressure inside the chamber was 0.5 Pa, and the cooling temperature of the main roller was -20℃. The two surfaces of the PET film were magnetron sputtered for 155 s respectively, thus preparing a copper layer with a thickness of 1000 nm on each of the two surfaces of the PET film, thereby obtaining a copper current collector with a thickness of 6.5 μm.

[0087] 2. Preparation of negative electrode-free lithium metal batteries

[0088] The preparation of the negative electrode-free lithium metal battery in this comparative example is the same as in Example 1.

[0089] Comparative Example 3

[0090] 1. Preparation of copper current collectors

[0091] The procedure is basically the same as in Example 1, except that the target current is 43A and the processing time is 6s. The rest of the operation is the same as in Example 1.

[0092] 2. Preparation of negative electrode-free lithium metal batteries

[0093] The preparation of the negative electrode-free lithium metal battery in this comparative example is the same as in Example 1.

[0094] Test case

[0095] 1. Experimental Construction Method

[0096] The cycle performance of the composite current collector prepared based on this application and the assembled battery was tested here. The specific test methods are as follows:

[0097] (1) Relative texture coefficient (RTC) of copper grains along the (100) crystal plane: The copper current collector or current collector prepared in the above-described embodiments and comparative examples is prepared according to the sample preparation requirements of X-ray diffractometer (XRD), and then placed in XRD. The sample is scanned at a speed of 2 degrees / min in the range of 5-90 degrees to obtain the XRD pattern of the sample. Then, the diffraction intensity of crystal planes such as (111), (100), and (110) is obtained from the pattern. Finally, the RTC is calculated according to the following formula.

[0098] In the formula, I(100) is the diffraction intensity of the (100) crystal plane in the XRD pattern, and I0(100) is the standard diffraction intensity of the copper (100) crystal plane; I(111) is the diffraction intensity of the (111) crystal plane in the XRD pattern, and I0(111) is the standard diffraction intensity of the copper (111) crystal plane; I(110) is the diffraction intensity of the (110) crystal plane in the XRD pattern, and I0(110) is the standard diffraction intensity of the copper (110) crystal plane.

[0099] (2) Elongation at break: The elongation at break of the copper current collector or copper foil in the above-described embodiments and comparative examples were tested in accordance with the national standard GB / T 1040.3-2006.

[0100] (3) Roughness: Take a flat 100mm×100mm current collector sample and place it in a high-precision roughness tester (Beijing Times TR260) to test the surface roughness Ra of the sample.

[0101] (4) Number of pore defects per unit area: The copper current collector or copper foil sample prepared in the above-described embodiments and comparative examples is placed in a surface quality detection system (micro-visual charge-coupled device CCD), its surface is scanned, and then the optical signal is converted into an electrical signal and transmitted to a computer to count the number of pore defects per unit area of ​​the composite current collector.

[0102] (5) Cyclic performance: The batteries prepared in the above-described embodiments and comparative examples were placed in a cycle performance testing device and a charge-discharge cycle experiment was conducted at a rate of 0.2C and a cycle charge-discharge voltage range of 3.0V-3.8V. The battery capacity retention rate after 100 cycles of charge-discharge was recorded.

[0103] 2. Experimental Results

[0104] The relevant performance of the copper current collector or copper foil in all the above embodiments and comparative examples, and the relevant test results of the batteries prepared using them are shown in Table 1.

[0105] Table 1. Performance test results of copper current collectors or copper foils and batteries in the examples and comparative examples.

[0106]

[0107] As can be seen from the table above:

[0108] As can be seen from Examples 1-10 and Comparative Examples 1, 2, and 3, compared with traditional copper foil and traditional copper current collectors, the copper current collector prepared in this application has a higher relative texture coefficient (RTC) along the (111) crystal plane orientation of the copper layer grains. （ 111 ） Maintaining the relative texture coefficient (RTC) within a specific range of 20-50% ensures that the copper current collector has good mechanical properties such as tensile strength and elongation at break, which is beneficial to improving the processability of the copper current collector in the battery electrode process and optimizing the battery cycle performance. Furthermore, with the relative texture coefficient (RTC) along the (111) crystal plane orientation... （ 111 ） The decrease in RTC leads to a reduction in tensile strength. Therefore, in order to ensure the mechanical properties of the prepared current collector, the RTC... (111) ≥20%. The improved capacity retention of the negative electrode-free lithium metal battery based on the copper current collector of this application after 100 cycles, i.e., improved charge-discharge cycle performance, is due to the increased RTC in the copper layer of the copper current collector. （ 111 ） This is due to the reduction, as RTC... （ 111 ）The reduction in the roughness of the copper layer leads to a decrease in the orientation of the grains along the (111) crystal plane. Since the (111) crystal plane of copper has a low lattice matching degree with the (111) crystal plane of lithium, more uniform lithium deposition is achieved. Furthermore, due to the high elongation at break of the copper current collector, it can effectively withstand the cyclic stress during charge-discharge cycles, maintaining a relatively stable state under long-term charge-discharge cycles, which is beneficial for further optimizing the cyclic charge-discharge performance of electrodeless lithium metal batteries. In addition, the current collector prepared in this application has lower roughness, thereby promoting uniform lithium deposition and improving the cycle performance of batteries based on this current collector.

[0109] From Examples 1-4, Example 10, and Comparative Example 3, it can be seen that increasing the current of radio frequency magnetron sputtering results in better copper current collectors and copper RTCs. （ 111 ） The reduction in RTC (111) increases the plasticity of the copper current collector, resulting in a larger elongation at break, which in turn improves the processability of the copper current collector in the battery electrode process. The improved capacity retention of the electrodeless lithium metal battery based on the copper current collector of this application after 100 cycles, i.e., improved charge-discharge cycle performance, is due to the reduction in RTC (111) in the copper layer of the copper current collector. As RTC (111) decreases, the orientation of the grains along the (111) crystal plane in the copper layer decreases. Since the (111) crystal plane of copper has a low lattice matching degree with the (111) crystal plane of lithium, more uniform lithium deposition is achieved. Furthermore, increasing the current of radio frequency magnetron sputtering reduces the surface roughness of the prepared copper current collector, further promoting uniform lithium deposition. Both factors contribute to the improvement of the battery's charge-discharge cycle performance. However, the current should not be too high. If the current is too high, the energy during sputtering is too high, which can easily break down the polymer film and form pore defects, thereby leading to a deterioration in the tensile strength, elongation at break of the copper current collector, and the cycle performance of the assembled battery. However, if the current is too low, the roughness of the prepared copper current collector will increase, which is not conducive to the uniform deposition of lithium during battery cycling, thus leading to a deterioration in the battery's cycle performance.

[0110] As can be seen from Examples 1, 5, 6 and 9: Increasing the thickness of the copper layer improves the RTC of the prepared copper current collector. （ 111 ） The tensile strength remains unchanged, while the elongation at break decreases. Based on this application's copper current collector, the capacity retention rate of the electrodeless lithium metal battery after 100 cycles is improved, indicating improved charge-discharge cycle performance. This improvement is due to the increased conductivity resulting from the increased thickness of the copper current collector layer. The copper layer thickness should not be too low, as this will lead to poor conductivity and consequently, a decrease in the battery's charge-discharge cycle performance.

[0111] As can be seen from Examples 1, 7, and 8, replacing the polymer film with other types of materials can still achieve good application results.

Claims

1. A copper current collector, comprising a substrate layer and a copper layer disposed on at least one side of the substrate layer; The relative texture coefficient RTC of the grains in the copper layer along the (111) crystal plane all satisfy: 20%≤RTC≤50%.

2. A copper current collector, wherein: The roughness range is Ra≤80nm.

3. The copper current collector as described in claim 1, wherein: One side of the substrate layer includes a copper layer, and the other side includes an aluminum layer.

4. The copper current collector as described in claim 1, wherein: The copper layer satisfies any one or more of the following conditions: (1) The thickness of the copper layer is not less than 100 nm; (2) The copper content in the copper layer is not less than 80 wt%.

5. The copper current collector as described in claim 1, wherein: The copper layer satisfies any one or more of the following conditions: (1) The thickness of the copper layer is not less than 500 nm; (2) The copper content in the copper layer is not less than 99.5 wt%.

6. The copper current collector as described in claim 1, wherein: The thickness of the copper layer is 500~2000nm.

7. The copper current collector as described in claim 1, wherein: The thickness of the copper layer is 800~1200nm.

8. The copper current collector as described in claim 3, wherein: The aluminum layer satisfies any one or more of the following conditions: (1) The thickness of the aluminum layer is not less than 100 nm; (2) The aluminum layer contains not less than 80 wt% aluminum.

9. The copper current collector as described in claim 3, wherein: The aluminum layer satisfies any one or more of the following conditions: (1) The thickness of the aluminum layer is not less than 500 nm; (2) The aluminum layer contains not less than 99.5 wt% aluminum.

10. The copper current collector as described in claim 3, wherein: The thickness of the aluminum layer is 500~2000nm.

11. The copper current collector as described in claim 3, wherein: The thickness of the aluminum is 800~1200nm.

12. The copper current collector as described in claim 1, wherein: The substrate layer satisfies any one or more of the following conditions: (1) The thickness of the substrate layer is 1~10μm; (2) The substrate layer includes at least one of polymer film, organic fiber layer, carbon layer, inorganic material layer, and conductive particles; (3) The substrate layer includes a polymer film, and the polymer film is made of one or more of the following materials: polyethylene terephthalate, polypropylene, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene ether, polystyrene, and polyimide. Alternatively, the substrate layer may include conductive particles, which may include at least one of carbon materials and metallic materials.

13. A method for preparing a copper current collector as described in any one of claims 1 to 11, wherein: The specific steps are as follows: Using the polymer film as a base film, copper layers are deposited on both sides of the polymer film by magnetron sputtering; wherein the magnetron sputtering current is 10~40A, the magnetron sputtering radio frequency is 13.56 MHz, the deposition time is 4~240s, the working pressure is not higher than 5Pa, and the inert gas flow rate is 20-300mL / min.

14. The method for preparing a copper current collector as described in claim 12, wherein the inert gas comprises argon.

15. The application of a copper current collector as described in any one of claims 1 to 11 in lithium-ion batteries, conductive components, magnetic materials, or electromagnetic shielding products.

16. An electrode sheet, wherein, This includes the copper current collector as described in any one of claims 1 to 11 or the copper current collector prepared by the method described in claim 7.

17. A lithium metal battery without a negative electrode, wherein: This includes the copper current collector as described in any one of claims 1 to 11, the copper current collector prepared by the method described in claim 7, or the electrode as described in claim 10.

18. The negative electrode-free lithium metal battery as described in claim 16, wherein: The negative electrode-free lithium metal battery also includes a positive electrode, which includes lithium iron phosphate positive electrode material.

19. The negative electrode-free lithium metal battery as described in claim 17, wherein: The positive electrode also includes a conductive agent and a binder, and the mass ratio of the lithium iron phosphate positive electrode material, the conductive agent, and the binder is 94~98:1.5~3.5:1~2.

5.

20. The negative electrode-free lithium metal battery of claim 18, wherein: The conductive agent includes one or more of conductive carbon black and carbon nanotubes; the binder includes one or more of polyvinylidene fluoride, polyacrylic acid, and polymethyl methacrylate.

21. An electrical appliance, wherein, Includes the electrode as described in claim 15 or the negative electrode-free lithium metal battery as described in any one of claims 16 to 19.

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