Polyarylether-based current collector surface modification method and application of polyarylether-based current collector surface modification method in lithium-poor battery

Abstract

The invention provides a surface modification method of a polyarylether-based current collector and application of the polyarylether-based current collector in a poor lithium battery, and belongs to the technical field of lithium metal batteries, and the surface modification method specifically comprises the following steps: dissolving a polyarylether high-molecular polymer, a polymer solid electrolyte and a lithium salt into an organic solvent, stirring and dissolving to obtain a precursor solution, the polyarylether high-molecular polymer contains an arylene group, a nitrile group, an oxygen ether group and a lithium-philic group; and spinning the precursor solution on the surface of the current collector through an electrostatic spinning technology to obtain a modified film with uniform fiber size, thereby obtaining the composite current collector. The polyarylether high-molecular polymer is modified on the surface of the current collector through an electrostatic spinning technology, so that the lithium deposition uniformity is improved, volume expansion caused by lithium deposition is effectively relieved, the cycling stability and the energy efficiency of the lithium metal battery are improved, the service life of the lithium metal battery is prolonged, and the lithium metal battery is particularly suitable for a lithium-poor battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium metal batteries, and in particular relates to a method for modifying the surface of a polyarylether-based current collector and an application thereof in lithium-deficient batteries. Background Art

[0002] With the increasing demand for energy storage and the improvement of environmental protection requirements, the cycle life and energy density of lithium metal batteries have always been the focus of current research. Lithium metal is considered to be the most ideal candidate for negative electrode materials due to its extremely high theoretical capacity (3860mAh / g) and low electrochemical potential (-3.04V vs. standard hydrogen electrode). The lithium negative electrode used in lithium metal batteries in actual work includes lithium foil and a certain amount of lithium pre-deposited on the current collector. On the one hand, lithium has high chemical reactivity. The higher the lithium content, the greater the potential safety hazards of battery operation. On the other hand, under the current lithium metal production process, it is difficult to reduce the thickness of lithium foil to below 50μm, which means that there is a large amount of unused lithium metal in the lithium negative electrode, which will not only increase the overall weight and volume of the battery, but also the excess lithium is more likely to produce more side reactions with the electrolyte, accelerate the consumption of the electrolyte, and ultimately affect the battery cycle life. Therefore, in the context of saving lithium resources and improving energy density, it is very necessary to reduce the amount of lithium metal used in practical applications. Lithium-deficient batteries came into being. There is no separate lithium negative electrode. All active lithium is initially stored in the positive electrode material. During the initial charging process, the active lithium is extracted from the positive electrode to the negative electrode and directly electroplated on the current collector in situ.

[0003] Since the commercialization of the Sony battery in 1991, copper has been used as a current collector on the anode side of the battery due to its excellent conductivity, ductility and stability at low potential. However, commercially available copper current collectors have micro-cracks and pits at the micro-nano scale, which can be called "defect points". In lithium-poor batteries, these "defect points" have lower charge transfer resistance than other surface locations, so they can act as "hot spots" for rapid nucleation and growth of lithium, resulting in uneven lithium deposition, causing uneven local current density distribution, increasing the internal resistance of the battery, and ultimately leading to irreversible deposition of lithium and shortening the cycle life, thereby limiting the further improvement of the performance of lithium-poor batteries.

[0004] In order to overcome the above problems, researchers began to explore the modification of copper current collectors by surface modification methods, and developed new surface modification technologies to improve the conductivity, chemical stability and mechanical stability of current collectors, and optimize the lithium nucleation and growth, local current density and lithium ion flux distribution on the surface of current collectors. For example, in his recent work (Refined Pore Structure Design and Surface Modification of 3D Porous Copper Achieving Highly Stable Dendrite-Free Lithium-Metal Anode), Professor Yao Yagang of Nanjing University loaded Cu2Se / Cu2O heterostructure nanowires on the surface of copper current collectors by anodic oxidation and chemical vapor deposition as nucleation sites for lithium kinetic enhancement. Although this method can achieve excellent interface conductivity and stability, methods such as vacuum evaporation, plasma surface treatment technology, chemical etching, electrochemical etching, sputtering, etc. are difficult to apply in actual production. In addition, Zhang et al. (A Natural Biopolymer Film as a Robust Protective Layer to Effectively Stabilize Lithium-Metal Anodes) disclosed that a natural biopolymer extracted from seaweed can be coated on the copper surface to show high ionic conductivity and elasticity. This polymer film allows lithium ions to migrate through the agarose film and deposit underneath it. However, during the battery cycle, due to mechanical stress, volume change or electrochemical reaction, the modified layer may gradually fall off or break, causing it to fail, thereby affecting the overall stability of the electrode. Summary of the invention

[0005] In view of the problems of uneven lithium deposition, low lithium recycling rate and volume expansion during the cycle caused by poor interface stability of the above-mentioned existing lithium-deficient batteries, the present invention provides a method for surface modification of a polyarylether-based current collector and its application in lithium-deficient batteries. The polyarylether polymer is modified on the surface of the current collector through electrospinning technology. While improving the uniformity of lithium deposition, the volume expansion caused by lithium deposition is effectively alleviated, thereby improving the cycle stability, energy efficiency and service life of lithium metal batteries, which is particularly suitable for lithium-deficient batteries.

[0006] In order to achieve the above purpose, the technical method adopted by the present invention is as follows:

[0007] A method for modifying the surface of a polyarylether-based current collector comprises the following steps:

[0008] Step 1, dissolving a polyarylether polymer, a polymer solid electrolyte and a lithium salt in an organic solvent, stirring and dissolving to obtain a precursor solution; wherein the polyarylether polymer contains an arylene group, a nitrile group, an oxygen ether group and a lithium-philic group; the mass fraction of the polyarylether polymer in the precursor solution is 12% to 20%, the mass fraction of the polymer solid electrolyte is 0.1% to 1%, and the concentration of the lithium salt is 0.01 to 0.5 mol / L;

[0009] Step 2: Spin the precursor solution onto the surface of the current collector through electrospinning technology to obtain a modified film with uniform fiber size, thereby obtaining a composite current collector.

[0010] Furthermore, the material of the current collector is copper.

[0011] Furthermore, the lithium-philic group is a sulfonic acid group, a sulfonyl group, or a carboxylic acid group.

[0012] Furthermore, the polyarylether polymer is phenolphthalein type polyarylether nitrile (PPL-PEN) or sulfonated polyarylether nitrile (SPEN).

[0013] Furthermore, the polymer solid electrolyte is one or more of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and polycarbonate (PC).

[0014] Furthermore, the lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium perchlorate (LiClO4), lithium chloride (LiCl), and lithium sulfate (Li2SO4).

[0015] Furthermore, in step 1, the stirring temperature is 40 to 80° C., and the stirring time is 16 to 36 hours.

[0016] Furthermore, step 2 is carried out at an ambient temperature of 30-40° C. and a humidity of 40%-60%.

[0017] Furthermore, the specific process parameters of the spinning are:

[0018] A 25-gauge bottle-mouth needle was used; a 5-mL syringe was used; the collector was fixed on a metal drum, and the receiving speed was controlled to be 200 rpm; the receiver was 10 cm away from the needle tip; the speed of the booster was 0.01 to 0.1 mm / min; a positive high voltage of 11 to 21 kV was applied to form a stable Taylor cone, and a negative high voltage of -5 to -1 kV was used for receiving, and spinning was continued for 3 to 5 hours.

[0019] Furthermore, the preparation process of the polyarylether polymer is as follows:

[0020] A diphenol compound, a bisphenol compound, an aromatic compound and a strong alkaline catalyst are added to a polar organic solvent, and under nitrogen protection, the obtained mixed solution is heated to 110-120° C. and kept stirring for dehydration for 2-4 hours; then kept at 140-160° C. for 3-5 hours to fully form small molecular oligomers; finally, kept at 170-190° C. for 3-6 hours to obtain a polyarylether polymer; wherein the molar ratio of the diphenol compound, the bisphenol compound, the aromatic compound and the strong alkaline catalyst is (0.1-0.9): (0.1-0.9): (1.1-1.5): (1.5-2), and the solid / liquid mass ratio of the polycondensation reaction at 140-160° C. and 170-190° C. is 1 / 5-2 / 3, without considering the amount of the alkaline catalyst.

[0021] Furthermore, the diphenol compound is one or a mixture of bisphenol A, bisphenol AP, and bisphenol Z; the bisphenol compound is one or a mixture of 2,5-dihydroxybenzenesulfonate potassium, 1,2-dihydroxynaphthalene-6-sulfonate potassium, 1,4-dihydroxynaphthalene-6-sulfonate potassium, bisphenol S, and phenolphthalein; the aromatic compound is 2,6-difluorobenzonitrile (DFBN) or 2,6-dichlorobenzonitrile (DCBN); the strong alkaline catalyst is one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium carbonate; the polar organic solvent is one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and toluene.

[0022] The invention also proposes the application of the obtained composite current collector in lithium-deficient batteries.

[0023] Furthermore, the negative electrode of the lithium-deficient battery is a composite current collector, and during the operation of the lithium-deficient battery, lithium is uniformly deposited on the surface of the composite current collector.

[0024] Furthermore, the electrolyte of the lithium-deficient battery is a mixed solution of lithium nitrate (LiNO3) and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) dissolved in one or more of ethylene glycol dimethyl ether (DME), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; the positive electrode material is LiNi 0.8 Co 0.1 Mn 0.1 O 0.2 , LiFePO4 or S.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention proposes a method for modifying the surface of a polyarylether-based current collector, wherein the surface of the current collector is modified by using a polyarylether-based high molecular polymer. The main chain of the polyarylether-based high molecular polymer contains a rigid arylene group, a nitrile group, and a lithium-philic oxygen ether group, and the side chain is rich in lithium-philic groups-sulfonic acid groups; wherein, one oxygen ether group can coordinate and bond with one lithium ion, and one sulfonic acid group can coordinate and bond with three lithium ions, so that the composite current collector has a lithium-philic property, realizes uniform deposition of lithium during battery operation, and induces spontaneous and uniform diffusion of lithium ions to the negative electrode side; the rigid arylene group helps to improve the mechanical strength of the polyarylether-based high molecular polymer, and the nitrile group will cause dipole-dipole interaction between molecular chains, and the formed cross-linked network will further enhance the physicochemical stability of the polyarylether-based high molecular polymer;

[0027] 2. The present invention modifies the polyarylether polymer on the surface of the current collector by electrospinning technology, so that the composite current collector has a high specific surface area and provides an elastic storage space for lithium deposition, effectively alleviating volume expansion;

[0028] 3. The present invention adds a polymer solid electrolyte to the precursor solution, which not only synergistically transports lithium ions to deposit on the composite current collector, but also strengthens the adhesion between the modified film and the current collector, preventing the modified film from falling off the surface of the current collector;

[0029] 4. The composite current collector obtained by the present invention is suitable for various types of lithium metal batteries, especially for lithium-deficient batteries. By optimizing the physical and chemical properties of the current collector surface, the cycle stability, energy efficiency and service life of the lithium metal battery are improved, providing strong technical support for the commercial application of lithium metal batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 The schematic diagram of the synthesis of the sulfonated polyarylethernitrile in Example 1, and the schematic diagram of the coordination bonding between the oxygen ether group, the sulfonic acid group and the lithium ion;

[0032] Figure 2 This is a SEM (scanning electron microscope) image of the NF-Cu modified membrane obtained in Example 1;

[0033] Figure 3 This is a statistical diagram of the fiber particle size of the NF-Cu modified membrane obtained in Example 1;

[0034] Figure 4 A comparison diagram of the electrolyte contact angles on the surfaces of the NF-Cu composite current collector and the Bared-Cu current collector obtained in Example 1;

[0035] Figure 5 The coulombic efficiency of lithium ion plating / stripping on the surface of the NF-Cu composite current collector and the Bared-Cu current collector obtained in Example 1;

[0036] Figure 6 The NF-Cu composite current collector and the Bared-Cu current collector obtained in Example 1 were pre-deposited with 10 mAh / cm 2 Li||Li-Cu half-cell cycle curve after lithium;

[0037] Figure 7 The NF-Cu composite current collector and the Bared-Cu current collector obtained in Example 1 were pre-deposited with 5 mAh / cm 2 Li||S full cell cycling curves after lithium. DETAILED DESCRIPTION

[0038] In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention. All raw materials of the present invention are not particularly limited in their sources, and can be purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0039] Example 1

[0040] This embodiment provides a method for modifying the surface of a polyarylether-based current collector, in which the surface of the current collector is modified by using a polyarylether-based high molecular polymer.

[0041] The polyarylether polymer used in this embodiment is SPEN, and its synthesis process is as follows: Figure 1 As shown, specifically:

[0042] In a 500mL three-necked flask, 11.41g of bisphenol A (0.05mol), 10.61g of potassium 2,5-dihydroxybenzenesulfonate (0.05mol), 23.35g of 2,6-dichlorobenzonitrile (0.11mol) and 22.11g of potassium carbonate (0.16mol) were added; then, 60mL of N-methylpyrrolidone and 20mL of toluene were added to the flask as polar organic solvents; the resulting mixture was heated to 120°C under nitrogen protection and kept stirring for dehydration for 3h; then kept at 150°C for 4h to fully form small molecular oligomers; finally kept at 180°C for 4h to obtain SPEN.

[0043] The synthesis process of SPEN mainly utilizes nucleophilic substitution condensation reaction. Its main chain has a large number of arylene groups, nitrile groups (-CN), and lithium-philic groups - oxygen ether groups that provide polymer rigidity, and the side chains are also rich in lithium-philic groups - sulfonic acid groups; among them, one oxygen ether group can coordinate and bond with one lithium ion, and one sulfonic acid group can coordinate and bond with three lithium ions; the rich nitrile groups in the main chain will also cause dipole-dipole interactions between molecular chains, and the formed cross-linked network will further enhance the physicochemical stability of SPEN.

[0044] Using the synthesized SPEN, this embodiment provides a method for surface modification of a polyarylether-based current collector, comprising the following steps:

[0045] Step 1, adding 1g of synthesized SPEN, 0.01g of polyethylene oxide, and 0.2g of lithium bis(trifluoromethanesulfonyl imide) to 6mL of N,N-dimethylformamide, stirring and dissolving at 60°C for 12h to obtain a precursor solution; wherein the mass fraction of SPEN is 13.6%, the mass fraction of polyethylene oxide is 0.1%, and the concentration of lithium bis(trifluoromethanesulfonyl imide is 0.11mol / L;

[0046] Step 2: The precursor solution is spun onto the surface of the copper current collector by electrospinning technology to obtain a NF-Cu modified film with uniform fiber size, and then a NF-Cu composite current collector is obtained; wherein, the spinning is carried out in a dry room with a dew point of 55°C, and the specific process parameters are: the ambient temperature is 35°C, a 25-gauge flat-mouth needle is used, and the precursor solution is pushed at a speed of 0.05mL / min through a 5mL syringe. The copper current collector is fixed on a metal drum, and the receiving speed is controlled to be 200rpm. The receiver is 10cm away from the needle tip, and a positive high voltage of 18kV is applied to form a stable Taylor cone. At the same time, a negative high voltage of -2kV is applied for receiving, and spinning is continued for 4h.

[0047] The SEM image of the NF-Cu modified membrane obtained in this example is shown in Figure 2 As shown, it can be seen that the fiber structure obtained by spinning is continuous and uniform, without beads and nodules; Figure 3 From the fiber particle size statistics shown, it can be seen that the distribution of fiber particle size is concentrated in the range of 50 to 300 nm, with an average diameter of 170.6 nm, reflecting the high uniformity of the fiber.

[0048] A pure copper current collector (denoted as Bared-Cu current collector) was used as a comparison to explore the advanced properties of the NF-Cu composite current collector obtained in this example.

[0049] First, the electrolyte of the lithium metal battery was prepared by dissolving 1 wt % lithium nitrate (LiNO 3 ) and 1 M lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) in a mixed solvent of ethylene glycol dimethyl ether (DME) and 1,3-dioxolane (DOL) in a volume ratio of 50:50.

[0050] The electrolyte contact angles on the surfaces of the NF-Cu composite current collector and the Bared-Cu current collector were measured respectively. The results are shown in Figure 4 As shown, it can be seen that the electrolyte contact angle of the unmodified Bared-Cu current collector surface is 46°. After modification with the NF-Cu modified film, the electrolyte contact angle on the surface of the NF-Cu composite current collector is reduced to 12°, indicating that the introduction of the NF-Cu modified film can reduce the surface energy of the copper current collector, and lithium ions are more easily dispersed on the surface of the copper current collector, which is beneficial to improve the deposition kinetics of lithium ions and promote the uniform deposition of lithium ions on the surface of the copper current collector.

[0051] Secondly, the deposition / stripping efficiency and stability of lithium on the surface of NF-Cu composite current collector and Bared-Cu current collector were evaluated by assembling Li||Cu half-cells. Specifically, the NF-Cu composite current collector and Bared-Cu current collector were cut into electrode discs of 16 mm in size, and the negative electrode shell, NF-Cu composite current collector (Bared-Cu current collector), 20 μL electrolyte, PP separator, 20 μL electrolyte, lithium sheet, gasket, shrapnel and positive electrode shell were installed in order from bottom to top.

[0052] When testing the lithium deposition / stripping efficiency on the surface of the NF-Cu composite current collector and the Bared-Cu current collector, the cycle parameters of the Li||Cu half-cell are set as follows: first, at 1 mA / cm 2 1 mAh / cm was deposited under the conditions of 2 , and then at 1mA / cm 2 Stripped to 1V. Test results are as follows Figure 5 As shown in the figure, the Li||Cu half-cell based on the Bared-Cu current collector began to fluctuate in the 68th cycle, while the Li||Cu half-cell based on the NF-Cu composite current collector showed good cycle stability in the first 170 cycles, and the coulombic efficiency was greater than 99%. This is mainly due to the dendrite growth of the Bared-Cu current collector during the deposition process, which led to the irreversible utilization of lithium. After being modified with the NF-Cu modified film, it can induce the uniform deposition of lithium and improve the recycling efficiency of lithium ions.

[0053] When conducting the cycle stability test of the Li||Cu half-cell based on the NF-Cu composite current collector and the Bared-Cu current collector, the cycle parameters of the Li||Cu half-cell were set as follows: 10 mAh / cm 2 , and obtain a Li||Li-Cu half-cell, and then at 8 mA / cm 2 -1mAh / cm 2 Charge and discharge cycle. Test results are as follows Figure 6 As shown in the figure, thanks to the presence of the NF-Cu modified film, the distribution of lithium ions on the surface of the NF-Cu composite current collector is more uniform, allowing lithium to be deposited in a more planar manner. Therefore, the Li||Li-Cu half-cell based on the NF-Cu composite current collector still maintains a small overpotential of 100mV after 700h of cycling. However, the Li||Li-Cu half-cell based on the Bared-Cu current collector showed severe polarization after 300h. The main reasons are the slow migration of lithium ions to the negative electrode, the uneven distribution of lithium ion concentration, and the high overpotential caused by severe concentration polarization, which ultimately led to battery failure.

[0054] Finally, in order to evaluate the potential of NF-Cu composite current collector in practical applications, the cycling stability was evaluated by assembling Li||S full cells. 5 mAh / cm 2 of lithium metal, at 1 mg / cm 2 The sulfur load is used as the positive electrode sheet to construct a Li||S full battery with a low N / P (~3) ratio, where the N / P ratio refers to the capacity ratio of the negative electrode (N) to the positive electrode (P) material in the battery. Under normal circumstances, N / P < 5 can be called a lithium-poor battery. The cycle stability results are shown in Figure 2. Figure 7 As shown, the initial specific capacity of the Li||S full battery based on the NF-Cu composite current collector at 0.1C is 1097mAh / g, and the capacity at the 386th cycle under 0.5C cycle is still 956mAh / g, with a capacity retention rate of more than 87%, which is much higher than the capacity retention rate of 27.8% of the Li||S full battery based on the NF-Cu composite current collector under the same test conditions, indicating that the NF-Cu composite current collector helps to improve the cycle stability and service life of lithium metal batteries.

[0055] Example 2

[0056] This embodiment provides a method for surface modification of a polyarylether-based current collector. Compared with Embodiment 1, the only difference is that PPL-PEN is used as a polyarylether polymer to prepare a NF-Cu composite current collector; the other preparation processes are exactly the same.

[0057] Example 3

[0058] This embodiment provides a method for surface modification of a polyarylether-based current collector. Compared with Embodiment 1, the only difference is that the concentration of lithium bis(trifluoromethanesulfonyl)imide is adjusted to 0.5 mol / L; the other preparation processes are exactly the same.

[0059] Example 4

[0060] This embodiment provides a method for surface modification of a polyarylether-based current collector. Compared with Embodiment 1, the only difference is that the concentration of lithium bis(trifluoromethanesulfonyl)imide is adjusted to 0.01 mol / L; the other preparation processes are exactly the same.

[0061] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enables any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the text of the claims, or if they include equivalent structural elements that are not substantially different from the text of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for surface modification of a polyarylether-based current collector, It is characterized in that The following steps are involved: Step 1, dissolving a polyarylether polymer, a polymer solid electrolyte and a lithium salt in an organic solvent, stirring and dissolving to obtain a precursor solution; wherein the polyarylether polymer contains an arylene group, a nitrile group, an oxygen ether group and a lithium-philic group; the mass fraction of the polyarylether polymer in the precursor solution is 12% to 20%, the mass fraction of the polymer solid electrolyte is 0.1% to 1%, and the concentration of the lithium salt is 0.01 to 0.5 mol / L; Step 2: Spin the precursor solution onto the surface of the current collector through electrospinning technology to obtain a modified film with uniform fiber size, thereby obtaining a composite current collector.

2. The method for surface modification of a polyarylether-based current collector according to claim 1, It is characterized in that The lithium-philic group is a sulfonic acid group, a sulfonyl group or a carboxylic acid group.

3. The method for surface modification of a polyarylether-based current collector according to claim 1, It is characterized in that The polyarylether macromolecular polymer is phenolphthalein type polyarylether nitrile or sulfonated polyarylether nitrile.

4. The method for surface modification of a polyarylether-based current collector according to claim 1, It is characterized in that The polymer solid electrolyte is one or more of polyethylene oxide, polyvinylidene fluoride, polyacrylonitrile and polycarbonate.

5. The method for surface modification of a polyarylether-based current collector according to claim 1, It is characterized in that The lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, lithium chloride and lithium sulfate.

6. The method for surface modification of a polyarylether-based current collector according to claim 1, It is characterized in that The stirring temperature in step 1 is 40 to 80° C. and the stirring time is 16 to 36 hours.

7. The method for surface modification of a polyarylether-based current collector according to claim 1, It is characterized in that Step 2 is performed at an ambient temperature of 30 to 40° C. and a humidity of 40% to 60%.

8. The method for surface modification of a polyarylether-based current collector according to claim 1, It is characterized in that The specific process parameters of the spinning are: A 25-gauge bottle-mouth needle was used; a 5-mL syringe was used; the collector was fixed on a metal drum, and the receiving speed was controlled to be 200 rpm; the receiver was 10 cm away from the needle tip; the speed of the booster was 0.01 to 0.1 mm / min; a positive high voltage of 11 to 21 kV was applied to form a stable Taylor cone, and a negative high voltage of -5 to -1 kV was used for receiving, and spinning was continued for 3 to 5 hours.

9. Use of the composite current collector obtained according to the method according to any one of claims 1 to 8 in lithium-deficient batteries.

10. A lithium-deficient battery, It is characterized in that The negative electrode is a composite current collector obtained by the method according to any one of claims 1 to 8, and during the operation of the lithium-deficient battery, lithium is uniformly deposited on the surface of the composite current collector.

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