Preparation method and application of hollow hybrid composite current collector with lithium metal confinement deposition function

Abstract

The invention provides a preparation method and application of a hollow hybrid composite current collector with a lithium metal confinement deposition function, and the preparation method comprises the following steps: S1, adding deionized water, ethanol and ammonia water into a container to obtain a first mixed solution, adding tetraethyl orthosilicate, stirring, and centrifuging and drying the obtained solid product to obtain silicon spheres; s2, metal salt, a carbon source and silicon balls are added into deionized water to be mixed, and a second mixed solution is obtained; s3, evaporating the deionized water from the second mixed solution to obtain a precursor; s4, carbonizing the precursor to obtain an intermediate; s5, after silicon balls are etched off from the intermediate, fluoridation, nitridation and phosphating are conducted, and a hollow ball composite material is obtained; and S6, coating a current collector with the hollow sphere composite material to obtain the hollow hybrid composite current collector. The lithium metal can be effectively guided to be uniformly deposited in the current collector, the generation of lithium dendrites and the volume expansion of the current collector can be inhibited, meanwhile, rigid SEI rich in inorganic components can be derived, and the lithium metal battery has a confinement effect and can be used for a lithium metal battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of protection of negative electrode materials of lithium metal batteries, and in particular relates to a preparation method and application of a hollow hybrid composite current collector with lithium metal confined deposition function. Background Art

[0002] In the context of "new energy storage", building a high-energy, efficient and economical electric energy storage system (EES) is the most important part. Among the various alternatives to lithium-ion batteries, lithium metal is considered to be the "holy grail" of the next generation of lithium-ion batteries because of its ultra-high specific capacity (3860mAh g-1 or 2061mAh cm-3) and extremely low electrochemical potential (-3.04V relative to standard hydrogen potential). The widespread application of LMB requires stable cycle performance, but lithium metal itself has the characteristic of "no owner". + It can be directly electroreduced and deposited on the negative electrode surface, which causes uneven lithium deposition and uncontrollable dendrite growth. To solve these problems, researchers have proposed a series of modification strategies, among which the current collector modification strategy has low cost, high efficiency, wide applicability and can be scaled up in proportion, which has important production implementation significance. However, conventional current collector modification methods have single functions, complex synthesis and high costs, which are difficult to meet the requirements of high-energy lithium metal batteries.

[0003] Patent CN110544733A discloses a method for preparing a three-dimensional porous confined MOFs current collector for lithium metal negative electrode, comprising the steps of adding a carbon source and a salt template to deionized water for dissolution to obtain a uniform and transparent precursor solution; spray drying to obtain a dry solid powder; heating to 500-750°C in an inert gas atmosphere, keeping the temperature for a period of time, and then rapidly cooling to obtain a calcined product; filtering to remove NaCl, and drying to obtain a three-dimensional porous carbon material; taking dimethylimidazole, methanol, zinc acetate and the prepared three-dimensional porous carbon, uniformly mixing and then standing at room temperature for a period of time to obtain a layered solution, and obtaining a precursor after centrifugation; calcining to obtain a product, which is called a three-dimensional porous carbon confined MOFs composite material; and obtaining a three-dimensional porous carbon confined MOFs composite current collector.

[0004] Patent CN 113540402A discloses an internal lithium-philic multi-confined / induced lithium negative electrode and its preparation method and application, including a flat metal current collector and an active layer composited on the surface of the flat metal current collector; the active layer includes an adhesive and a multi-confined / induced 3D carbon composite skeleton material dispersed in the adhesive, the carbon composite skeleton is a pomegranate-like multi-thin-wall carbon layer encapsulation structure, that is, it is formed by encapsulating several nano-composite carbon balls with micron hollow carbon balls; the nano-composite carbon balls are nano-hollow carbon balls with a strong lithium-philic precious metal nanoparticle structure embedded in the inner wall, and the micron hollow carbon balls are nitrogen-doped carbon spheres with a diameter of microns; the carbon composite skeleton has abundant filling chambers, which are filled with lithium metal element.

[0005] The above two methods for protecting the zinc negative electrode have the following disadvantages: (1) The synthesis method is complicated, with many steps and a long time consumption; (2) The function is relatively single and cannot provide all-round protection for lithium metal; (3) The cost is high and cannot meet the requirements of high-energy-density lithium metal batteries. Summary of the invention

[0006] The purpose of the present invention is to provide a preparation method and application of a hollow hybrid composite current collector with lithium metal confined deposition function, which can effectively guide lithium metal to deposit uniformly inside the current collector and inhibit the generation of lithium dendrites and the volume expansion of the current collector, and can also derive a rigid SEI rich in inorganic components, which has a confined effect and can be used in lithium metal batteries, and can effectively improve the coulombic efficiency and cycle stability of the battery. The process is simple, the cost is low, and it is suitable for industrial production.

[0007] In order to achieve the above purpose, this application adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a hollow hybrid composite current collector having a lithium metal confined deposition function, comprising the following steps:

[0009] S1: adding a certain volume ratio of deionized water, ethanol and ammonia water into a container to obtain a first mixed solution, then adding a certain amount of tetraethyl orthosilicate into the first mixed solution, stirring for a certain period of time, centrifuging and drying the obtained solid product to obtain silicon balls;

[0010] S2: adding the metal salt, the carbon source and the silicon balls into deionized water in a certain proportion and stirring the mixture to obtain a second mixed solution;

[0011] S3: placing the second mixed solution in a drying oven to evaporate the deionized water to obtain a precursor;

[0012] S4: carbonizing the precursor under an inert gas atmosphere to obtain an intermediate;

[0013] S5: etching away the silicon spheres from the intermediate in a fluorine-containing environment and then subjecting the intermediate to fluorination, nitridation and phosphating treatments to obtain a hollow sphere composite material;

[0014] S6: coating the hollow sphere composite material on a current collector to obtain the hollow hybrid composite current collector.

[0015] In the above technical solution, in S1, the volume ratio of the deionized water, ethanol, ammonia water and tetraethyl orthosilicate is (0.5-1.5):(1-5):(1-1.5):(0.1-0.5).

[0016] In the above technical solution, in S1, the diameter of the silicon sphere is 100nm to 500nm.

[0017] In the above technical solution, in S2, the mass ratio of the metal salt, the carbon source and the silicon balls is (1-1.5): (0.5-1): (1-1.5).

[0018] In the above technical solution, in S2, the metal salt is one of cobalt nitrate, nickel nitrate, zinc nitrate, ferrous nitrate, ferric nitrate, and magnesium nitrate.

[0019] In the above technical scheme, in S2, it is characterized in that the carbon source is one of polyvinyl pyrrolidone, glucose, glucosamine, and ethylenediaminetetraacetic acid.

[0020] In the above technical solution, in S4, the carbonization temperature of the precursor is 700-900°C.

[0021] In the above technical solution, in S5, the etching time of the silicon ball is 1 to 3 hours.

[0022] In the above technical solution, in S5, the fluorine source used for etching and fluorination is one of polytetrafluoroethylene (PTFE), HF, and NH4F.

[0023] In the above technical solution, in S5, the nitrogen source used for nitridation is one of NH3, urea, and sodium amide.

[0024] In the above technical solution, in S5, the phosphorus source used for phosphating is one of sodium pyrophosphate, P2O5, disodium hydrogen phosphate, and aminophosphorus.

[0025] In a second aspect, the present invention provides the use of the hollow hybrid composite current collector prepared by the above-mentioned preparation method in the preparation of lithium metal batteries.

[0026] The beneficial effects of the present invention are:

[0027] The hollow hybrid composite current collector with lithium metal confined deposition function prepared by the preparation method provided by the present invention has a large specific surface area and a hollow structure that can not only provide sufficient space for lithium ion deposition, but also reduce the local current density to a great extent; the lithium-philic substance can be used as a lithium-philic site to reduce the nucleation barrier of lithium ions and induce the spatial deposition of lithium ions in the cavity. In addition, the lithium-philic substance can be derived into an SEI rich in inorganic components, thereby strengthening the SEI layer and inhibiting the formation of lithium dendrites and dead lithium; the carbon matrix can not only enhance the conductivity of the composite material, provide fast electron and ion transmission, but also maintain the integrity of the structure during continuous lithium deposition / stripping; the carbon composite material minimizes the increase in the mass of the current collector, ensuring the high energy density advantage of lithium-ion batteries. The lithium metal battery negative electrode material modified by this method has broad application prospects in the fields of energy storage and the like, and the preparation method is simple in process, generally applicable to various systems, suitable for industrial large-scale production, and low in cost and high in safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a SEM image of the silicon sphere of the present invention;

[0029] Figure 2 The SEM image of NiF2@C-HS provided in Example 1 of the present invention;

[0030] Figure 3 Provide a TEM image of FeF2@C-HS for Example 2 of the present invention;

[0031] Figure 4 The electrochemical polarization rate line graph with and without FeF2@C-HS provided in Example 2 of the present invention;

[0032] Figure 5 The XRD pattern of CoF2@C-HS provided in Example 3 of the present invention;

[0033] Figure 6 The N2 adsorption / desorption isotherm of CoF2@C-HS provided in Example 3 of the present invention;

[0034] Figure 7 The pore size distribution diagram of CoF2@C-HS provided in Example 3 of the present invention;

[0035] Figure 8 The electrochemical polarization line graph before and after the composite with or without Co3N2@C-HS provided in Example 4 of the present invention;

[0036] Fig. 9 The electrochemical polarization line graph of the composite with or without NiP@C-HS provided in Example 5 of the present invention;

[0037] Fig.10SEM images of different capacities of the current collector deposited with or without MgF2@C-HS provided in Example 6 of the present invention;

[0038] Fig.11 The electrochemical coulombic efficiency diagram with and without ZnP@C-HS provided in Example 7 of the present invention;

[0039] Fig.12 This is a full battery charge and discharge test diagram with and without CoF2@C-HS provided in Example 8 of the present invention. DETAILED DESCRIPTION

[0040] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. The present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete, and the concept of the present invention will be fully conveyed to those skilled in the art, and the present invention will only be limited by the claims.

[0041] like Figure 1-12 As shown, the present invention provides a method for preparing a hollow hybrid composite current collector having a lithium metal confined deposition function, comprising the following steps:

[0042] S1: adding a certain volume ratio of deionized water, ethanol and ammonia water into a container to obtain a first mixed solution, then adding a certain amount of tetraethyl orthosilicate into the first mixed solution, stirring for a certain period of time, centrifuging and drying the obtained solid product to obtain silicon balls;

[0043] S2: adding metal salt, carbon source and silicon balls into deionized water in a certain proportion and stirring the mixture to obtain a second mixed solution;

[0044] S3: placing the second mixed solution in a drying oven to evaporate the deionized water to obtain a precursor;

[0045] S4: carbonizing the precursor under an inert gas atmosphere to obtain an intermediate;

[0046] S5: etching away the silicon spheres from the intermediate in a fluorine-containing environment, and then performing fluorination, nitridation, and phosphating treatments to obtain a hollow sphere composite material;

[0047] S6: coating the hollow sphere composite material on a current collector to obtain a hollow hybrid composite current collector.

[0048] In S1, the volume ratio of deionized water, ethanol, ammonia water and tetraethyl orthosilicate is (0.5-1.5): (1-5): (1-1.5): (0.1-0.5). The diameter of the silicon sphere is 100nm-500nm.

[0049] In addition, during the preparation process, the diameter of the silicon spheres can be controlled by adjusting the ratio and rotation speed, and silicon spheres of different sizes can be customized to meet different needs.

[0050] In S2, the mass ratio of metal salt, carbon source and silicon balls is (1-1.5):(0.5-1):(1-1.5).

[0051] The metal salt is one of cobalt nitrate (Co(NO3)2·6H2O), nickel nitrate (Ni(NO3)2·6H2O), zinc nitrate (Zn(NO3)2·6H2O), ferrous nitrate (Fe(NO3)2·6H2O), ferric nitrate (Fe(NO3)3·6H2O), and magnesium nitrate (Mg(NO3)2·6H2O).

[0052] The carbon source is one of polyvinyl pyrrolidone (PVP), glucose, glucosamine, and ethylenediaminetetraacetic acid (EDTA).

[0053] The SEM image of the silicon ball is as follows Figure 1 shown.

[0054] In S3, the evaporation temperature of the mixed solution is maintained at 70-100° C. The time required for evaporation of the mixed solution is between 8 and 12 hours.

[0055] In S4, the carbonization temperature of the precursor is 700 to 900° C. The carbonization time of the precursor is 1 to 3 hours.

[0056] In S5, the etching time of the silicon ball is 1 to 3 hours, and the fluorination, nitridation and phosphation treatment time is 1 to 3 hours.

[0057] The fluorine source used for etching and fluorination is one of polytetrafluoroethylene (PTFE), HF, and NH4F.

[0058] The nitrogen source used for nitridation is one of NH3, urea, and sodium amide.

[0059] The phosphorus source used for phosphating is one of sodium pyrophosphate, P2O5, disodium hydrogen phosphate, and amino phosphate.

[0060] The present invention also provides the application of the prepared hollow hybrid composite current collector in the preparation of lithium metal batteries. The hollow hybrid composite current collector is used to assemble symmetrical batteries, Li / / Cu half-cells, and full-cells for testing to prove its confinement effect on metallic lithium and its protective effect on the negative electrode material of lithium metal batteries.

[0061] The electrolyte used when assembling the battery is one of an ester electrolyte and an ether electrolyte.

[0062] The concentration of the electrolyte used when assembling the battery is within the range of 1 to 3M.

[0063] The positive electrode materials used in assembling full batteries are LiFePO4, LiCoO2, LiMnO2, LiNi 0.8 Co 0.1 Mn 0.1 02. LiNi 0.5 Co 0.2 Mn 0.3 02 LiNi 0.6 Co 0.2 Mn 0.2 02One of them.

[0064] This will be explained below through a specific implementation plan and product test results.

[0065] Example 1

[0066] 0.5 g of glucose and 1.0 g of Ni(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then, 1.0 g of silica spheres with a diameter of 500 nm were added to the solution and stirred for 30 min. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 80 °C for 12 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The product was calcined at 700 °C for 2 h in an argon atmosphere at a heating rate of 10:1. Finally, the product was ground with polytetrafluoroethylene (PTFE) powder at a mass ratio of 10:1 and heated at 5 °C min in an argon atmosphere. -1 The resulting product was calcined in a tube furnace at 600 °C for 2 h with a heating rate of 1.5 % and finally formed into the desired NiF2@C-HS composite material.

[0067] See also Figure 2 , is the SEM image of NiF2@C-HS in this embodiment.

[0068] Example 2

[0069] 1 g of EDTA and 1.2 g of Fe(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then, 1.5 g of silica spheres with a diameter of 500 nm were added to the solution and stirred for 1 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 100 °C for 10 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The product was calcined at 700 °C for 2 h in an argon atmosphere at a heating rate of 1.5 °C / min. Finally, the product was ground with NH4F powder at a mass ratio of 10:1 and heated at 5 °C / min in an argon atmosphere. -1 The resulting FeF2@C-HS composite material was calcined at 600 °C in a tube furnace for 1 h at a heating rate of 1.

[0070] See also Figure 3 , is the TEM image of FeF2@C-HS in this embodiment, and it can be seen that it has a hollow structure.

[0071] See also Figure 4 , which is a line graph of the electrochemical polarization rate with and without FeF2@C-HS in this example, indicating that the FeF2@C-HS composite material can indeed play a protective role on the lithium metal negative electrode, especially under high current conditions.

[0072] Example 3

[0073] 0.5 g of polyvinyl pyrrolidone and 1.0 g of Co(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then 1 g of silica spheres with a diameter of 300 nm was added to the solution and stirred for 2 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 120 °C for 12 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The product was calcined at 800 °C for 1.5 h in an argon atmosphere at a heating rate of 1.5 °C. Finally, the product was ground with PTFE powder at a mass ratio of 10:1 and heated at 5 °C min in an argon atmosphere. -1 The resulting product was calcined at 600 °C in a tube furnace for 1 h at a heating rate to finally form the desired CoF2@C-HS composite material.

[0074] See also Figure 5 , which is the XRD pattern of CoF2@C-HS in this example, proving the successful synthesis of CoF2@C-HS.

[0075] See also Figure 6 , which is the N2 adsorption / desorption isotherm of CoF2@C-HS in this example, proving the existence of microporous and mesoporous structures.

[0076] See also Figure 7 , which is the pore size distribution diagram of CoF2@C-HS in this example, proves that the pore size is mainly composed of mesopores and macropore structures. The enlarged cavity can redistribute the electric field and reduce the local current density, and provide sufficient free space for lithium metal deposition.

[0077] Example 4

[0078] 1 g of glucosamine and 1.5 g of Co(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then 1.3 g of silica spheres with a diameter of 200 nm were added to the solution and stirred for 1 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 100 °C for 12 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min-1 The intermediate was calcined at 750 °C in an argon atmosphere at a heating rate of 1.5 h. Next, the intermediate was immersed in HF to etch away the silicon spheres for 1 h. Finally, the intermediate was heated in an NH3 atmosphere at 5 °C min -1 The resulting product was calcined at 700 °C in a tube furnace for 1 h at a heating rate to finally form the desired Co3N2@C-HS composite material.

[0079] The composite material and polyvinylidene fluoride (PVDF) were prepared into a slurry in a mass ratio of 9:1, coated on a copper foil and dried at 80°C to obtain a current collector, and then a half-cell was assembled using a lithium sheet as a negative electrode and the current collector as a positive electrode.

[0080] See also Figure 8 , which is the electrochemical polarization line graph before and after the composite with or without Co3N2@C-HS in this example, indicating that CoN@C-HS can indeed play a protective role and maintain a long cycle time.

[0081] Example 5

[0082] 1 g of glucosamine and 1.5 g of Ni(NO3)2-6H2O were dissolved in 300 mL of deionized water to obtain a uniformly mixed solution. Then 1.3 g of silica spheres with a diameter of 100 nm were added to the solution and stirred for 1.5 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 110 °C for 10 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The intermediate was then calcined at 900°C in an argon atmosphere at a heating rate of 2 h. Next, the intermediate was immersed in HF to etch away the silicon spheres for 2 h. Finally, the intermediate and P2O5 were heated in an inert gas atmosphere at 5°C min -1 The resulting NiP@C-HS composite was calcined at 800 °C in a tube furnace for 2 h at a heating rate of 1.5 %.

[0083] The composite material was mixed with polyvinylidene fluoride (PVDF) in a mass ratio of 9:1 to prepare a slurry, which was coated on a copper foil and dried at 80 °C to obtain a current collector. A half-cell was then assembled using a lithium sheet as the negative electrode and the current collector as the positive electrode. 3 mAh cm -2 A symmetrical battery is obtained by adding metallic lithium.

[0084] See also Fig. 9 , which is the electrochemical polarization line graph before and after the composite with or without NiP@C-HS in this example, indicating that NiP@C-HS can indeed play a protective role and maintain a long-term cycle time.

[0085] Example 6

[0086] 0.5 g of polyvinyl pyrrolidone and 1.0 g of Mg(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then 1 g of silica spheres with a diameter of 500 nm was added to the solution and stirred for 2 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 120 °C for 12 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The product was calcined at 800 °C for 1.5 h in an argon atmosphere at a heating rate of 1.5 °C. Finally, the product was ground with PTFE powder at a mass ratio of 10:1 and heated at 5 °C min in an argon atmosphere. -1 The MgF2@C-HS composite material was finally formed by calcining at 600 °C in a tube furnace for 1 h at a heating rate of 1.

[0087] The composite material and polyvinylidene fluoride (PVDF) were prepared into a slurry in a mass ratio of 9:1, coated on a copper foil and dried at 80°C to obtain a current collector, and then a half-cell was assembled using a lithium sheet as a negative electrode and the current collector as a positive electrode.

[0088] See also Fig.10 , which are SEM images of different capacities of current collector deposition with and without MgF2@C-HS in this example, indicate that MgF2@C-HS can play a confining role to store metallic lithium inside the hollow spheres and can induce uniform deposition of lithium metal, avoiding the formation of dendrites and dead lithium.

[0089] Example 7

[0090] 0.7 g of glucosamine and 1.5 g of Zn(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then 1 g of silica spheres with a diameter of 400 nm was added to the solution and stirred for 1.5 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 100 °C for 10 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The intermediate was then immersed in HF to etch away the silicon spheres for 2 h. Finally, 0.7 g of disodium hydrogen phosphate (upstream) and the intermediate (downstream) were placed on two separate ceramic boats in an alumina tube under an argon atmosphere and heated at 5 °C min -1 The ZnP@C-HS was calcined at 500 °C for 3 h at a heating rate of 1.5 %. Then, the ZnP@C-HS was coated on copper foil as the positive electrode and lithium metal was used as the negative electrode in an ether electrolyte at 1 mA cm -2 1mAh cm -2 The long-term cycle performance was tested under the conditions of

[0091] The composite material and polyvinylidene fluoride (PVDF) were prepared into a slurry in a mass ratio of 9:1, coated on a copper foil and dried at 80°C to obtain a current collector, and then a half-cell was assembled using a lithium sheet as a negative electrode and the current collector as a positive electrode.

[0092] See also Fig.11 , which is the electrochemical coulomb efficiency diagram with and without ZnP@C-HS in this example, indicates that ZnP@C-HS can indeed protect the lithium metal anode and maintain long cycle time and high efficiency at high current.

[0093] Example 8

[0094] 1 g of EDTA and 1.5 g of Co(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then 1.5 g of silica spheres with a diameter of 500 nm were added to the solution and stirred for 2 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 120 °C for 12 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The product was calcined at 700 °C in an argon atmosphere at a heating rate of 1.5 h. Finally, the product was ground with PTFE powder at a mass ratio of 10:1 and heated at 5 °C min in an argon atmosphere. -1 The resulting product was calcined at 600 °C in a tube furnace for 1 h at a heating rate to finally form the desired CoF2@C-HS composite material.

[0095] CoF2@C-HS was coated on copper foil as the positive electrode and metallic lithium was used as the negative electrode to form a half-cell. 2 mAh cm was deposited on the CoF2@C-HS current collector. -2 The battery was disassembled and used as a lithium metal negative electrode, and LiFePO4 as a positive electrode, and its life and capacity retention were tested in an ester electrolyte.

[0096] See also Fig.12 , which is the full battery charge and discharge test diagram with and without CoF2@C-HS in this example. When the current density is 1C, the full battery can maintain a capacity retention rate of 98% in a cycle of up to 300 cycles, indicating that the full battery with CoF2@C-HS as the current collector can maintain a long cycle time and high efficiency.

[0097] Example 9

[0098] 0.8 g of glucose and 1.2 g of Fe(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then 1 g of silica spheres with a diameter of 300 nm was added to the solution and stirred for 2 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 100 °C for 10 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The intermediate was calcined at 700 °C in an argon atmosphere at a heating rate of 1.5 h. Next, the intermediate was immersed in HF to etch away the silicon spheres for 1.5 h. Finally, 1 g of sodium pyrophosphate (upstream) and the intermediate (downstream) were placed on two separate ceramic boats in an alumina tube under an argon atmosphere and heated at 5 °C min -1 FeP@C-HS was obtained by calcining at 700 °C for 2 h with a heating rate of .

[0099] FeP@C-HS was coated on copper foil as the positive electrode and metallic lithium was used as the negative electrode to form a half-cell. 3 mAh cm was deposited on the FeP@C-HS current collector. -2 The battery is disassembled and used as a lithium metal negative electrode, with LiNi 0.8 Co 0.1 Mn 0.1 02 as the positive electrode, and its life and capacity retention were tested in an ester electrolyte. When the current density was 1C, the full battery was able to maintain a capacity retention rate of 99% in a cycle of up to 300 cycles, indicating that the full battery with FeP@C-HS as the current collector can maintain a long cycle time and high efficiency.

[0100] Example 10

[0101] 0.8 g of glucosamine and 1.2 g of Fe(NO3)2-6H2O were dissolved in 200 mL of deionized water to obtain a uniformly mixed solution. Then 1 g of silica spheres with a diameter of 200 nm was added to the solution and stirred for 2 h. After a uniform suspension was formed, it was transferred to a petri dish and evaporated at a constant temperature of 80 °C for 10 h. Subsequently, the obtained sample was taken out of the petri dish and heated in a tube furnace at 5 °C min -1 The intermediate was calcined at 700 °C in an argon atmosphere at a heating rate of 1.5 h. Next, the intermediate was immersed in HF to etch away the silicon spheres for 1.5 h. Finally, the intermediate was heated in an NH3 atmosphere at 5 °C min -1 The resulting FeN@C-HS composite was calcined at 700 °C in a tube furnace for 1 h at a heating rate of 1.5 %.

[0102] FeN@C-HS was coated on copper foil as the positive electrode and metallic lithium was used as the negative electrode to form a half-cell. 2 mAh cm was deposited on the FeN@C-HS current collector. -2The battery was disassembled and used as a lithium metal negative electrode, and LiNiO2 was used as a positive electrode to test its life and capacity retention in an ester electrolyte. When the current density was 2C, the full battery was able to maintain a capacity retention rate of 95% in a cycle of up to 270 cycles, indicating that the full battery with FeN@C-HS as the current collector can maintain a long cycle time and high efficiency.

[0103] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a hollow hybrid composite current collector having lithium metal confined deposition function, Features: The following steps are involved: S1: adding a certain volume ratio of deionized water, ethanol and ammonia water into a container to obtain a first mixed solution, then adding a certain amount of tetraethyl orthosilicate into the first mixed solution, stirring for a certain period of time, centrifuging and drying the obtained solid product to obtain silicon balls; S2: adding the metal salt, the carbon source and the silicon balls into deionized water in a certain proportion and stirring the mixture to obtain a second mixed solution; S3: placing the second mixed solution in a drying oven to evaporate the deionized water to obtain a precursor; S4: carbonizing the precursor under an inert gas atmosphere to obtain an intermediate; S5: etching away the silicon spheres from the intermediate in a fluorine-containing environment, and then performing fluorination, nitridation, and phosphating treatments to obtain a hollow sphere composite material; S6: coating the hollow sphere composite material on a current collector to obtain the hollow hybrid composite current collector.

2. The preparation method according to claim 1, Features: In S1, the volume ratio of the deionized water, ethanol, ammonia water and tetraethyl orthosilicate is (0.5-1.5):(1-5):(1-1.5):(0.1-0.5).

3. The preparation method according to claim 1, Features: In S1, the diameter of the silicon sphere is 100nm to 500nm.

4. The preparation method according to claim 1, Features: In S2, the mass ratio of the metal salt, the carbon source and the silicon balls is (1-1.5): (0.5-1): (1-1.5).

5. The preparation method according to claim 1, Features: In S2, the metal salt is one of cobalt nitrate, nickel nitrate, zinc nitrate, ferrous nitrate, ferric nitrate, and magnesium nitrate.

6. The preparation method according to claim 1, Features: S2 is characterized in that the carbon source is one of polyvinyl pyrrolidone, glucose, glucosamine, and ethylenediaminetetraacetic acid.

7. The preparation method according to claim 1, Features: In S5, the fluorine source used for etching and fluorination is polytetrafluoroethylene (PTFE), HF, NH 4 FOne of them.

8. The preparation method according to claim 1, Features: In S5, the nitrogen source used for nitridation is NH 3 , urea, or sodium amide.

9. The preparation method according to claim 1, Features: In S5, the phosphorus source used for phosphating is sodium pyrophosphate, P 2 O 5 , disodium hydrogen phosphate, or amino phosphate.

10. Use of the hollow hybrid composite current collector prepared by the preparation method according to any one of claims 1 to 9 in the preparation of lithium metal batteries.

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