Preparation method and application of copper current collector surface lithiumophilic nanofiber interface layer

Abstract

The application discloses a preparation method and application of a lithium-philic nanofiber interface layer on a copper current collector surface, and the preparation method comprises the following steps: adding copper hydroxide into a solvent and uniformly mixing, adding a polymer matrix and uniformly mixing to obtain a spinning precursor solution; performing electrostatic spinning on the spinning precursor solution to obtain a nanofiber membrane; drying the nanofiber membrane to obtain a nanofiber layer; performing heat treatment on the nanofiber layer and cooling to room temperature to obtain a nanofiber interface layer. The nanofiber interface layer has a three-dimensional nanofiber network structure, can buffer huge volume changes during battery cycling, and can improve the stability of the electrode / electrolyte interface; the polymer matrix has a high specific surface area and a mutually connected pore structure, can provide a convenient ion / electron transmission channel, and can balance the charge distribution on the lithium negative electrode surface during the charging and discharging process; CuO particles can react with lithium to form a beneficial Li2O component, improve the interface stability and ion conductivity, and promote the uniform lateral deposition of lithium.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and specifically relates to a method for preparing and applying a lithium-loving nanofiber interface layer on the surface of a copper current collector. Background Technology

[0002] With the increasing popularity of new energy vehicles, the demand for battery safety and high energy density is growing. Lithium metal, with its ultra-high theoretical specific capacity (3860 mAh g⁻¹), is a promising candidate for this technology. −1 Lithium metal, with its extremely low redox potential (−3.040 V vs. standard hydrogen electrode), is considered an ideal anode material for high-energy-density batteries. Therefore, lithium metal batteries, using lithium metal as the anode, are expected to break through the current energy density bottleneck of lithium-ion batteries, significantly improving the driving range in applications such as mobile electronic devices and electric vehicles. However, the inherent high reactivity of lithium metal causes it to spontaneously react with any non-aqueous electrolyte to form an ion-conducting, electronically insulating solid electrolyte interface (SEI) film. To truly bring lithium metal batteries close to or meet the commercial requirements for high energy density and high safety, the following issues still need to be addressed:

[0003] (1) How to improve the uneven deposition / stripping behavior of lithium ions on the electrode surface and avoid the formation and growth of lithium dendrites;

[0004] (2) How to adjust the structural composition of the SEI layer generated on the electrode surface to improve its affinity for lithium metal and achieve uniform lithium nucleation and growth behavior;

[0005] (3) How to suppress the problem of electrode volume expansion / contraction during cycling and further promote the controllable construction of a uniform and stable SEI layer on the electrode surface. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a method for preparing a lithium-philic nanofiber interface layer on the surface of a copper current collector and its application, so as to improve the uneven deposition / stripping behavior of lithium ions on the electrode surface and regulate the structural composition of the SEI layer. Inorganic functional particles CuO particles can react with lithium to form beneficial Li2O components, while improving interface stability and ionic conductivity, and promoting uniform lateral deposition of lithium.

[0007] Therefore, the present invention provides a method for preparing a lithium-philic nanofiber interface layer on the surface of a copper current collector, comprising:

[0008] (1) Add copper hydroxide to the solvent and stir to mix evenly, then add the polymer matrix material and stir to mix evenly to obtain the spinning precursor solution;

[0009] (2) Electrospinning the spinning precursor solution to obtain a nanofiber membrane; the nanofiber membrane is dried by air drying and vacuum drying to obtain a nanofiber layer;

[0010] (3) The nanofiber layer is heat-treated and then cooled to room temperature to obtain a lithium-loving nanofiber interface layer on the surface of the copper current collector.

[0011] Preferably, in step (1), the mass ratio of copper hydroxide to polymer matrix material is (4-7):(10-20).

[0012] Preferably, in step (1), the polymer matrix material includes at least one of polyacrylonitrile, polyvinylidene fluoride, polyethylene oxide, and polydimethylsiloxane.

[0013] Preferably, in step (1), the polymer matrix material includes polyacrylonitrile and polyvinylidene fluoride, and the mass ratio of polyacrylonitrile to polyvinylidene fluoride is (1-3):(0.5-1.5).

[0014] Preferably, in step (1), the solvent is N,N-dimethylformamide, and the mass ratio of copper hydroxide to the volume ratio of the solvent is (0.42-0.8) g: (10-20) mL.

[0015] Preferably, step (2), the electrospinning method includes: wrapping the receiving roller of the electrospinning machine with copper foil, taking the spinning precursor liquid into the needle tube and connecting the needle, adjusting the distance between the needle and the receiving roller to 10-15cm; spinning for 1-3 hours under the conditions of needle tube advance rate of 1-3mL / h and spinning voltage of 15-30 kV to prepare a fiber membrane with a thickness of 20-30 μm and a width of 80-120 mm.

[0016] Preferably, in step (2), the blowing temperature is 50-80℃ and the time is 5-8h; the vacuum drying temperature is 50-80℃ and the time is 20-28h.

[0017] Preferably, step (3), the heat treatment method includes: placing the nanofiber layer in a furnace, heating it to 200-300 ℃ at a heating rate of 1-3℃ / min, heat-treating for 1-3 h, and then naturally cooling it to room temperature.

[0018] The present invention also provides the application of the prepared copper current collector surface lithiophilic nanofiber interface layer in batteries.

[0019] Compared with the prior art, the advantages and positive effects of this invention are as follows: This invention provides a method for preparing a lithium-loving nanofiber interface layer on the surface of a copper current collector and its application. This application combines organic polymers and inorganic functional particles through electrospinning. The prepared lithium-loving nanofiber interface layer on the surface of the copper current collector has a three-dimensional nanofiber network structure, which can serve as a host for lithium deposition. It can buffer the huge volume changes during battery cycling and improve the stability of the electrode / electrolyte interface. The polymer matrix has a high specific surface area and an interconnected pore structure, which can provide convenient ion / electron transport channels, balance the charge distribution on the lithium anode surface during charging and discharging, and achieve uniform lithium ion flux. The inorganic functional particles CuO particles can react with lithium to form beneficial Li2O components, while improving interface stability and ionic conductivity, promoting uniform lateral deposition of lithium, and synergistically regulating the deposition behavior of metallic lithium.

[0020] The lithiophilic nanofiber interface layer on the copper current collector surface prepared in this application can enhance the mechanical properties and flexibility of the SEI film to resist lithium dendrite damage. Furthermore, the lithiophilic nanofiber interface layer on the copper current collector surface of this application can also promote uniform lithium ion deposition and reduce lithium dendrite growth.

[0021] Other features and advantages of the present invention will become clearer after reading the detailed embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a SEM image of the Cu(OH)2@PVDF-PAN nanofiber membrane from Example 1 of the present invention;

[0023] Figure 2 This is a SEM image of the CuO@F-OPAN nanofiber membrane from Example 1 of the present invention.

[0024] Figure 3 The FTIR spectra of the PVDF-PAN nanofiber membrane and the F-OPAN nanofiber membrane in Example 2 of this invention are shown below.

[0025] Figure 4 Surface and cross-sectional SEM images of bare copper foil (Bare Cu) under different lithium deposition capacities;

[0026] Figure 5 Surface and cross-sectional SEM images of CuO@F-OPAN nanofiber films with different lithium deposition capacities;

[0027] Figure 6 This is one of the cycle performance test graphs of lithium copper batteries in Example 3, Comparative Example 1, and Comparative Example 2 under different current densities and different lithium deposition capacities;

[0028] Figure 7 This is the second graph showing the cycle performance test of lithium copper batteries in Example 3, Comparative Example 1, and Comparative Example 2 under different current densities and different lithium deposition capacities.

[0029] Figure 8 The lithium copper battery of Example 3 at 1 mA cm -2 and 1 mAh cm -2 Charge-discharge curves under different cycle numbers under the condition;

[0030] Figure 9 The lithium copper battery of Example 3 at 1 mA cm -2 and 1 mAh cm -2 Interfacial impedance test diagrams under different cycle numbers under the condition;

[0031] Figure 10 The lithium-free anode batteries of Example 4 and Comparative Example 3 were tested at 0.5 mA cm⁻¹. -2 The following is a graph showing the cyclic performance test results. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, after reading this invention, those skilled in the art can make various modifications or alterations to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] The method for preparing the lithium-philic nanofiber interface layer on the surface of the copper current collector of the present invention includes:

[0034] (1) Add copper hydroxide to the solvent and stir to mix evenly, then add the polymer matrix material and stir to mix evenly to obtain the spinning precursor solution;

[0035] The mass ratio of copper hydroxide to polymer matrix material is (4-7):(10-20).

[0036] The polymer matrix material may include at least one of polyacrylonitrile, polyvinylidene fluoride, polyethylene oxide, and polydimethylsiloxane.

[0037] In this embodiment, the polymer matrix material includes polyacrylonitrile and polyvinylidene fluoride, and the mass ratio of polyacrylonitrile to polyvinylidene fluoride is (1-3):(0.5-1.5).

[0038] Preferably, the mass ratio of copper hydroxide to the polymer matrix material is (4-5):(12-17), and the mass ratio of polyacrylonitrile to polyvinylidene fluoride is (1.5-2.5):(0.7-1.2). This allows the lithiophilic nanofiber interface layer on the copper current collector surface to have a three-dimensional nanofiber network structure, which can serve as a host for lithium deposition, buffering the large volume changes during battery cycling and improving the stability of the electrode / electrolyte interface. The polymer matrix has a high specific surface area and an interconnected pore structure, providing convenient ion / electron transport channels, balancing the charge distribution on the lithium anode surface during charging and discharging, and achieving uniform lithium-ion flux. The inorganic functional particles CuO particles can react with lithium to form beneficial Li2O components, while improving interface stability and ionic conductivity, promoting uniform lateral lithium deposition, and synergistically regulating the deposition behavior of metallic lithium. In addition, it can also enhance the mechanical properties and flexibility of the lithiophilic nanofiber interface layer on the copper current collector surface to resist the damage of lithium dendrites. Furthermore, the lithium-loving nanofiber interface layer on the surface of the copper current collector in this application can also promote the uniform deposition of lithium ions and reduce the growth of lithium dendrites.

[0039] Polyvinylidene fluoride (PVDF) exhibits good electrolyte wettability, high ionic conductivity, thermal stability, and chemical stability. PVDF's melting point is lower than the temperature of subsequent heat treatment processes, allowing it to remain in a molten state during these processes.

[0040] Polyacrylonitrile (PAN) contains a large number of polar groups and also has good thermal and chemical stability. PAN can undergo oxidation cyclization reaction during subsequent heat treatment processes, generating more polar groups on its surface.

[0041] The solvent is N,N-dimethylformamide, and the mass ratio of copper hydroxide to solvent is (0.42-0.8) g: (10-20) mL. This allows the copper hydroxide and polymer matrix material to be mixed evenly, so that the pre-spinning solution reaches a suitable viscosity, which is beneficial for the spinning of nanofibers. This results in uniform nanofiber output and no obvious droplets on the nanofiber membrane.

[0042] Preferably, the mass ratio of copper hydroxide to solvent is (0.42-0.5) g : (13-17) mL.

[0043] (2) Electrospinning the spinning precursor solution to obtain a fiber membrane; the fiber membrane is dried by air drying and vacuum drying to obtain a nanofiber membrane;

[0044] The electrospinning method includes: wrapping the receiving roller of an electrospinning machine with copper foil, taking the spinning precursor solution into a needle tube and connecting the needle, adjusting the distance between the needle and the receiving roller to 10-15 cm; spinning for 1-3 h under the conditions of a needle tube advance rate of 1-3 mL / h and a spinning voltage of 15-30 kV to prepare a nanofiber membrane with a thickness of 20-30 μm and a width of 80-120 mm. The electrospinning method of this invention is beneficial for the spinning of nanofibers, resulting in uniform nanofiber output and no obvious droplets on the nanofiber membrane.

[0045] The drying process involves blowing air at a temperature of 50-80℃ for 5-8 hours, and vacuum drying at a temperature of 50-80℃ for 20-28 hours. Both blowing air and vacuum drying methods allow the organic solvent N,N-dimethylformamide (DMF) in the fiber membrane to evaporate.

[0046] (3) Heat-treat the nanofiber membrane and then cool it to room temperature to obtain a lithium-loving nanofiber interface layer on the surface of the copper current collector.

[0047] The heat treatment method includes: placing the nanofiber membrane in a furnace, heating it to 200-300 °C at a heating rate of 1-3 °C / min, heat-treating for 1-3 h, and then naturally cooling to room temperature. Preferably, the heat treatment temperature is 260-300 °C, and the heat treatment time is 2-3 h.

[0048] The nanofiber interface layer prepared by this invention can be used to prepare batteries. Specifically, the nanofiber interface layer can be used as the negative electrode of the battery. The battery prepared by the nanofiber interface layer of this invention has excellent electrochemical stability and cycle performance.

[0049] The advantages and positive effects of this application include:

[0050] (1) Preparation of Lithophilic CuO@F-OPAN Nanofiber Layer-Based Artificial SEI Film: This application utilizes electrospinning and heat treatment processes to effectively construct a lithophilic CuO@F-OPAN nanofiber layer on the surface of copper foil, thus preparing an artificial SEI film. Heat treatment melts PVDF, which can be used as a pore size modifier or a physical bonding agent to accelerate Li... + The transfer of energy enables a tight bond between the copper foil and the lithiophilic CuO@F-OPAN nanofiber layer, effectively enhancing the interfacial stability and compatibility between the two, which is conducive to the long-term stable cycling of the battery.

[0051] (2) Regulation of lithium deposition / stripping behavior: Through thermal treatment, polyacrylonitrile (PAN) can be converted into oxidized polyacrylonitrile (OPAN) rich in polar groups; oxidized polyacrylonitrile (OPAN) has excellent Li-deposition / stripping behavior. +Affinity can enable Li within the three-dimensional nanofiber framework + Flux homogenization helps achieve uniform lithium deposition and avoids the growth of lithium dendrites.

[0052] Through heat treatment, Cu(OH)₂ particles can be converted in situ into lithiophilic CuO particles. The beneficial components formed by the redox reaction between CuO particles and metallic lithium lower the lithium nucleation energy barrier, promoting uniform lithium nucleation and growth, and facilitating uniform lateral lithium deposition. This synergistically regulates highly reversible lithium deposition / stripping behavior, improving the coulombic efficiency and long-term cycle stability of the battery. Furthermore, a three-dimensional nanofiber network serves as a flexible support for the SEI film, buffering electrode volume deformation during battery cycling and enhancing interfacial stability. Simultaneously, it guides uniform lithium deposition from bottom to top, forming a stable interface layer rich in LiF and Li₂O, thereby enhancing the electrochemical reversibility and stability of the lithium anode.

[0053] (3) Regulation of SEI film structure: A three-dimensional nanofiber network is used as a flexible support for the SEI film, and the SEI film is guided to form in situ within the small gaps between the fibers. This effectively suppresses the volume deformation of the electrode, endows the SEI film with good structural stability and flexibility, and thus avoids the SEI film from breaking due to changes in the volume of lithium metal. Benefiting from the co-modification of CuO and PVDF, a stable and robust LiF and Li2O-rich SEI interface layer is constructed in situ, which greatly promotes interfacial charge transfer, reduces parasitic reactions, and consolidates the electrode / electrolyte interface. This is conducive to the rapid development of high-energy-density and high-safety lithium-free anode batteries. Example 1

[0054] The method for preparing the lithium-philic nanofiber interface layer on the surface of the copper current collector in this embodiment includes the following steps:

[0055] (1) Preparation of spinning precursor solution:

[0056] Weigh 0.45 g of copper hydroxide (Cu(OH)2) and add it to 15 mL of N,N-dimethylformamide (DMF). Stir and sonicate the solution for 5 min. After the solution is thoroughly mixed, add 1 g of polyacrylonitrile (PAN) and 0.5 g of polyvinylidene fluoride (PVDF) to the above solution. Stir in a constant temperature water bath at 60℃ for 2 h until PAN and PVDF are completely dissolved to obtain the spinning precursor solution.

[0057] (2) Electrospinning preparation of nanofiber membranes:

[0058] Cut copper foil to a size of 32 cm × 25 cm and wrap it around the receiving roller of an electrospinning machine. Take 3 mL of the above-mentioned spinning precursor solution and connect it to an 800 μm diameter needle in the syringe. Adjust the receiving distance to 12 cm. Spin for 2 h at a syringe advance rate of 1.5 mL / h and a spinning voltage of 20 kV to prepare a nanofiber membrane with a thickness of 20-30 μm and a width of 90 mm. After drying by forced air (60℃ forced air for 6 h) and vacuum drying (60℃ vacuum drying for 24 h), Cu(OH)2@PVDF-PAN nanofiber membrane is obtained.

[0059] (3) Heat treatment

[0060] A 10 cm × 15 cm Cu(OH)2@PVDF-PAN nanofiber membrane was placed in a muffle furnace and heated to 260 ℃ at a heating rate of 2 ℃ / min. After heat treatment at 260 ℃ for 2 h, it was naturally cooled to room temperature to obtain a lithiophilic nanofiber interface layer on the surface of the copper current collector, denoted as CuO@F-OPAN nanofiber membrane. Example 2

[0061] The method for preparing the nanofiber interface layer in this embodiment includes the following steps:

[0062] (1) Preparation of spinning precursor solution:

[0063] 1 g of polyacrylonitrile (PAN) and 0.5 g of polyvinylidene fluoride (PVDF) were mixed and stirred in a constant temperature water bath at 60°C for 2 h until PAN and PVDF were completely dissolved to obtain a spinning precursor solution.

[0064] (2) Electrospinning preparation of nanofiber membranes:

[0065] Cut copper foil measuring 32 cm × 25 cm and wrap it around the receiving roller of an electrospinning machine. Take 3 mL of the above-mentioned spinning precursor solution and connect it to an 800 μm diameter needle in the syringe. Adjust the receiving distance to 12 cm. Spin for 2 h at a syringe advance rate of 1.5 mL / h and a spinning voltage of 20 kV to prepare a nanofiber membrane with a thickness of 20-30 μm and a width of 90 mm. After drying by forced air (60℃ forced air for 6 h) and vacuum drying (60℃ vacuum drying for 24 h), a PVDF-PAN nanofiber membrane is obtained.

[0066] (3) Heat treatment

[0067] A PVDF-PAN nanofiber membrane measuring 10 cm × 15 cm was placed in a muffle furnace and heated to 260 ℃ at a heating rate of 2 ℃ / min. After heat treatment at 260 ℃ for 2 h, it was naturally cooled to room temperature to obtain a lithium-loving nanofiber interface layer on the surface of a copper current collector, which was denoted as F-OPAN nanofiber membrane.

[0068] Figure 1 The image shows a SEM image of the Cu(OH)2@PVDF-PAN nanofiber membrane in Example 1 of this invention. The Cu(OH)2@PVDF-PAN nanofiber membrane is uniformly distributed and there are no liquid droplets on the fiber membrane.

[0069] Figure 2 This is a SEM image of the CuO@F-OPAN nanofiber membrane in Example 1 of the present invention. Since the heat treatment temperature is higher than the melting point of PVDF, PVDF will be in a molten state, and therefore the nanofibers will be in a partially molten state.

[0070] Figure 3 The FTIR spectra of the PVDF-PAN nanofiber membrane and the F-OPAN nanofiber membrane in Example 2 of this invention are shown below. A comparison of the infrared spectra before and after heat treatment reveals that the FTIR spectrum is at 2245 cm⁻¹. −1 The peak band of C≡N decreases sharply, located between 1580 and 1650 cm⁻¹. −1 The C=O and C=N peaks at 2940 cm⁻¹ increase sharply. −1 The reduction in nearby C-H bonds indicates that PAN underwent cyclization and partial oxidation after heat treatment.

[0071] Figure 4 Surface and cross-sectional SEM images of bare copper foil (Bare Cu) under different lithium deposition capacities. Figure 5 The images show surface and cross-sectional SEM images of CuO@F-OPAN nanofiber films under different lithium deposition capacities. After lithium deposition with different capacities, the fibrous morphology of the nanofiber layer is still visible, indicating that lithium preferentially deposits beneath the nanofiber layer. The thickness of the lithium deposition layer increases with increasing lithium deposition capacity. Compared to Bare Cu and F-OPAN, the lithium deposition layer of CuO@F-OPAN is thinner and the lithium distribution is more uniform. To further observe the morphology of lithium deposition beneath the nanofiber layer, part of the surface nanofiber layer was removed after lithium deposition. Bare Cu exhibits an uneven lithium deposition morphology. In contrast, CuO@F-OPAN shows a uniform, dendrite-free, spherical lithium deposition morphology beneath the nanofiber layer, and the deposition surface is more uniform and smooth. Example 3

[0072] The battery in this embodiment is a lithium copper battery, and the positive electrode of the lithium copper battery is a lithium sheet.

[0073] The copper foil supporting the CuO@F-OPAN nanofiber membrane from Example 1 was cut into 10 mm diameter discs to serve as the negative electrode, a lithium sheet as the positive electrode, and a 19 mm diameter polyethylene membrane as the separator. The battery was assembled using 80 μL of ether electrolyte. The ether electrolyte consisted of 1.0 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 2 wt.% lithium nitrate (LiNO3), and a solvent comprising 1,3-dioxolane (DOL) and dimethyl ethylene glycol ether (DME) in a 1:1 volume ratio. Example 4

[0074] The battery in this embodiment is a lithium-free negative electrode battery, and the positive electrode of the lithium-free negative electrode battery includes LiFePO4. A positive electrode slurry is prepared by mixing lithium iron phosphate (LiFePO4), conductive carbon black (Super P), and PVDF in a mass ratio of 8:1:1, using N-methylpyrrolidone (NMP) as a solvent and grinding. The slurry is then uniformly coated onto carbon-coated aluminum foil with a coating thickness of 180 μm using a scraper. After being dried by forced air (60°C for 6 hours) and vacuum dried (60°C for 24 hours), it is cut into 10 mm diameter discs to serve as the positive electrode of the lithium-free negative electrode battery.

[0075] The copper foil supported on the CuO@F-OPAN nanofiber membrane from Example 1 was used as the negative electrode, and a polyethylene membrane with a diameter of 16.5 mm was used as the separator. A battery was assembled using 40 μL of ether electrolyte. The ether electrolyte consisted of 1.0 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 2 wt.% lithium nitrate (LiNO3), and a solvent comprising 1,3-dioxolane (DOL) and dimethyl ethylene glycol ether (DME) in a 1:1 volume ratio.

[0076] Comparative Example 1

[0077] The lithium copper battery of Comparative Example 1 is basically the same as the lithium copper battery of Example 3, except that the negative electrode of the lithium copper battery of Comparative Example 1 is copper foil.

[0078] Comparative Example 2

[0079] The lithium copper battery of Comparative Example 2 is basically the same as the lithium copper battery of Example 3, except that the negative electrode of the lithium copper battery of Comparative Example 2 is the F-OPAN nanofiber membrane of Example 2.

[0080] Comparative Example 3

[0081] The lithium-free anode battery of Comparative Example 3 is basically the same as the lithium-free anode battery of Example 4, except that the anode of the lithium-free anode battery of Comparative Example 3 is copper foil.

[0082] Figure 6This is one of the cycle performance test graphs of lithium copper batteries in Example 3, Comparative Example 1, and Comparative Example 2 under different current densities and different lithium deposition capacities; Figure 7 This is the second graph showing the cycle performance test results of lithium-copper batteries from Examples 3, 1, and 2 at different current densities and lithium deposition capacities. At different current densities and lithium deposition capacities, CuO@F-OPAN exhibits better cycle stability than F-OPAN and Bare Cu. At a current density of 1 mA / cm²... -2 The lithium deposition capacity is 1 mAh / cm³. -2 At that time, CuO@F-OPAN can maintain a stable cycle of 230 cycles, with a coulombic efficiency of over 98%.

[0083] Figure 8 The lithium copper battery of Example 3 at 1 mA cm -2 and 1 mAh cm -2 The charge-discharge curves under different cycle numbers are shown in the figure. The polarization voltage of CuO@F-OPAN did not increase significantly after 250 cycles, and the charge-discharge curves under different cycle numbers almost overlapped, showing good reversibility in the lithium deposition / stripping process.

[0084] Figure 9 The lithium copper battery of Example 3 at 1 mA cm -2 and 1 mAh cm -2 Interfacial impedance test diagrams under different cycling numbers under the conditions; the lithium copper battery loaded with CuO@F-OPAN showed little impedance change after 150 cycles under the conditions of 1 mA cm-2 and 1 mAh cm-2, forming a stable SEI layer.

[0085] Figure 10 The lithium-free anode batteries of Example 4 and Comparative Example 3 were tested at 0.5 mA cm⁻¹. -2 The cycle performance test results show that the lithium-free anode battery loaded with CuO@F-OPAN can maintain a capacity retention of 49.2% and an average coulombic efficiency of 99.3% after 100 cycles under 0.5 C conditions.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A method for preparing a lithium-philic nanofiber interface layer on the surface of a copper current collector, characterized in that, include: (1) Add copper hydroxide to the solvent and stir to mix evenly, then add the polymer matrix material and stir to mix evenly to obtain the spinning precursor solution; (2) Electrospinning the spinning precursor solution to obtain a nanofiber membrane; the nanofiber membrane is dried by air drying and vacuum drying to obtain a nanofiber layer; (3) The nanofiber layer is heat-treated and then cooled to room temperature to obtain a lithium-loving nanofiber interface layer on the surface of the copper current collector; The heat treatment method in step (3) includes: placing the nanofiber layer in a furnace and heating it to 200-300 ℃ at a heating rate of 1-3℃ / min, and then naturally cooling it to room temperature after heat treatment for 1-3 h.

2. The method for preparing a lithium-philic nanofiber interface layer on the surface of a copper current collector according to claim 1, characterized in that, In step (1), the mass ratio of copper hydroxide to polymer matrix material is (4-7):(10-20).

3. The method for preparing the lithium-philic nanofiber interface layer on the surface of a copper current collector according to claim 1, characterized in that, In step (1), the polymer matrix material includes at least one of polyacrylonitrile, polyvinylidene fluoride, polyethylene oxide, and polydimethylsiloxane.

4. The method for preparing the lithium-philic nanofiber interface layer on the surface of a copper current collector according to claim 3, characterized in that, In step (1), the polymer matrix material includes polyacrylonitrile and polyvinylidene fluoride. The mass ratio of polyacrylonitrile to polyvinylidene fluoride is (1-3):(0.5-1.5).

5. The method for preparing a lithium-philic nanofiber interface layer on the surface of a copper current collector according to claim 1, characterized in that, In step (1), the solvent is N,N-dimethylformamide. The mass ratio of copper hydroxide to solvent is (0.42-0.8) g : (10-20) mL.

6. The method for preparing a lithium-philic nanofiber interface layer on the surface of a copper current collector according to claim 1, characterized in that, The electrospinning method in step (2) includes: wrapping the receiving roller of the electrospinning machine with copper foil, taking the spinning precursor liquid into the needle tube and connecting the needle, and adjusting the distance between the needle and the receiving roller to 10-15cm. A fiber membrane with a thickness of 20-30 μm and a width of 80-120 mm was prepared by spinning for 1-3 h at a needle advance rate of 1-3 mL / h and a spinning voltage of 15-30 kV.

7. The method for preparing a lithium-philic nanofiber interface layer on the surface of a copper current collector according to claim 1, characterized in that, In step (2), the blowing drying temperature is 50-80℃ and the time is 5-8h; Vacuum drying temperature is 50-80℃, time is 20-28h.

8. The application of the lithium-philic nanofiber interface layer on the surface of the copper current collector prepared according to any one of claims 1-7 in a battery.

Images