Carbon-based negative electrode current collector with lithiumophilic confinement structure, and preparation method and application thereof

Abstract

The application relates to a carbon-based negative electrode current collector with a lithium-philic confined structure and a preparation method and application thereof, and belongs to the technical field of electrochemical energy sources. The preparation of the carbon-based negative electrode current collector comprises the following steps: cleaning a carbon base; activating in a concentrated acid solution through water bath heating; soaking in a seed source solution containing metal oxides and alkali, drying after taking out, and repeating the soaking; immersing in a growth solution containing metal oxides and a crystallization regulator, carrying out a hydrothermal reaction to grow metal oxides on the carbon base, washing and drying after taking out; obtaining a carbon precursor-coated metal oxide carbon base; carrying out pyrolysis treatment; acid-etching part of the metal oxides to obtain the carbon-based negative electrode current collector with the lithium-philic confined structure. The battery assembled by using the three-dimensional carbon-based current collector has the advantages that under the conditions of a current density of 1 mA / cm 2 and a deposition amount of 4 mAh / cm 2 , the average coulombic efficiency can still reach about 99.53% after 100 cycles, and the battery has good cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy technology, specifically relating to a carbon-based negative electrode current collector with a lithiophilic confined structure, its preparation method, and its application. Background Technology

[0002] High-energy-density rechargeable batteries have become one of the most important technologies of the 21st century, with wide applications ranging from miniaturized electronic products to all-electric vehicles and smart grids. Lithium-ion batteries possess advantages such as high energy density, long cycle life, no memory effect, high operating voltage, low self-discharge, and environmental friendliness, making them widely used in various fields. For lithium-ion batteries, graphite anodes are typically used to meet safety requirements, but their theoretical capacity is only 372 mAh / g, which cannot meet the growing demand for higher energy-density energy storage devices. Lithium metal shows the greatest potential for achieving a leap in lithium battery energy density and is considered an ideal anode due to its light weight (0.534 g / cm³). 3 This novel electrodeless lithium metal battery boasts an ultra-high specific capacity (3862 mAh / g) ten times higher than that of graphite anodes, and also exhibits an extremely low redox potential (-3.040 V vs. standard hydrogen electrode). The theoretical energy density of this new electrodeless lithium metal battery can reach over 500 Wh / kg, while the energy density of ordinary lithium-ion batteries is generally between 100-300 Wh / kg. However, electrodeless lithium metal batteries still have some problems, such as the formation of lithium dendrites potentially leading to internal short circuits, low cycle efficiency, and poor stability, all of which affect battery performance and safety. Solving these problems mainly involves the following aspects: improving the electrolyte, constructing an artificial interface layer, optimizing testing methods, and designing current collector substrates.

[0003] Introducing lithiophilic sites on the surface of current collectors can improve their lithiophilicity and homogenize lithium deposition. Hou et al. synthesized a lithiophilic layer formed by silver nanoparticle alloying on copper foil. The uniform silver nanoparticles can serve as lithium nucleation sites to induce lithium growth on the copper current collector, achieving uniform lithium nucleation and stable lithium plating / stripping. Although surface lithiophilic modification induces uniform lithium deposition and can promote cycle stability to some extent, most surface coatings are easily damaged or pulverized, failing to address the volume change problem during plating / stripping. The three-dimensional structural design of copper-based current collectors is currently a research hotspot. Yu et al. used graphene-modified three-dimensional copper foam as a current collector to suppress lithium dendrite growth and promote uniform lithium deposition. Its unique porous structure can provide more space to accommodate lithium metal deposition, thus achieving a confinement function and suppressing volume expansion to some extent. However, the lattice mismatch between copper current collector materials and lithium metal (BCC) significantly affects the lithium nucleation potential. Carbon-based current collectors possess advantages such as high conductivity, large specific surface area, light weight, and good chemical stability. Three-dimensional carbon-based current collectors, in particular, can reduce local current density along the negative electrode surface, mitigating dendrite growth. Guo et al. used graphitized carbon fibers as a multifunctional three-dimensional current collector. The high surface area provided by carbon fibers reduced local current density, facilitating uniform electrochemical deposition, suppressing dendrite formation, and effectively mitigating volume changes during lithium plating / stripping. However, the problems of active material shedding and large volume changes during repeated cycling remain unresolved. Jin et al. used carbon-coated zinc oxide nanotubes as the negative electrode for lithium-ion batteries; the carbon-coated nanotube structure reduced the volume changes of the zinc oxide active material. He et al. invented a method for preparing a three-dimensional porous carbon-coated zinc oxide current collector, which effectively suppresses volume expansion during lithium metal deposition and desorption, the formation of lithium dendrites, and the further generation of dead lithium, which leads to battery capacity decay. Existing technologies, such as three-dimensional carbon cloth-supported ZnOnanorod arrays as binder-free anodes for lithium-ion batteries, suffer from significant volume expansion and poor cycle stability, resulting in performance inferior to this invention. Existing technologies, such as the solvent-free synthesis of N-doped carbon-coated ZnO nanorods composite anode via a ZnO support-induced ZIF-8 in-situ growth strategy, cannot effectively grow lithium dendrites, also resulting in performance inferior to this invention. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention aims to design and provide a carbon-based anode current collector with a lithiophilic confined structure, its preparation method, and its application. The carbon-based anode current collector of the present invention is prepared by a hydrothermal method followed by heat treatment.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing a carbon-based negative electrode current collector with a lithiophilic confined structure, comprising the following steps:

[0007] (1) Take a carbon substrate and clean the slurry on the surface;

[0008] (2) The carbon substrate cleaned in step (1) is placed in a concentrated acid solution and activated by water bath heating. After removal, it is dried.

[0009] (3) The carbon substrate activated in step (2) is immersed in a seed source solution containing metal oxides and alkali, then removed and dried, and repeatedly immersed.

[0010] (4) Immerse the carbon substrate obtained in step (3) in a growth solution containing metal oxides and crystallization regulators to carry out a hydrothermal reaction to grow metal oxides on the carbon substrate. After taking it out, wash it and dry it.

[0011] (5) Using the carbon substrate obtained in step (4) as a template, aldehyde compounds and phenolic compounds are added, and a polymerization reaction is carried out in a mixed solution of ammonia, ethanol and deionized water. After drying, a metal oxide carbon substrate coated with carbon precursor is obtained.

[0012] (6) The carbon precursor-coated metal oxide carbon substrate is heated to the pyrolysis temperature under an inert atmosphere and subjected to pyrolysis treatment; (7) After cooling, some metal oxides are etched with acid, washed until neutral, and dried to obtain a carbon-based negative electrode current collector with a lithium-loving confined structure.

[0013] In the preparation method described above, the carbon substrate in step (1) is any one of carbon cloth, carbon paper, graphene, and carbon nanotubes;

[0014] The cleaning method includes ultrasonic cleaning in acetone, ethanol and deionized water in sequence.

[0015] In the preparation method described above, the concentrated acid solution in step (2) is any two or more of concentrated sulfuric acid (AR), concentrated nitric acid (AR), and concentrated hydrochloric acid (AR); the water bath heating time is 0.5 to 10 hours, and the temperature is 25 to 50°C; the drying temperature is 60 to 90°C.

[0016] Preferably, the concentrated acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, wherein the ratio of concentrated sulfuric acid to concentrated nitric acid is 1 to 5:1 (V:V);

[0017] More preferably, concentrated sulfuric acid: concentrated nitric acid = 3:1 (V:V);

[0018] Preferably, the water bath heating time is 4 hours;

[0019] Preferably, the water bath heating temperature is 30°C;

[0020] Preferably, the drying temperature is 80°C.

[0021] In the preparation method described above, the soaking time in step (3) is 1 to 30 minutes, the drying temperature is 25 to 100°C, and the number of soaking times is 1 to 5.

[0022] Preferably, the soaking time is 10 minutes, the drying temperature is 90°C, and the soaking is repeated 3 times;

[0023] The metal oxide is selected from AgNO3, Al(NO3)2, etc. 3)3 At least one of Zn(NO3)2, Zn(NO3)2·6H2O, Zn(CH3COO)2·2H2O, ZnSO4·7H2O, SnCl2·2H2O, SnCl4, NiSO4, Mg(NO3)2, Ni(CH3COO)2 and FeSO4;

[0024] The alkali is selected from at least one of KOH, NaOH and ammonia water;

[0025] The preparation process of the seed source solution is as follows: 0.1-1 mol of anhydrous ethanol solution of metal oxide is mixed with 0.1-1 mol of anhydrous ethanol solution of alkali, stirred at 1-1000 r / min for 1-60 min, and then allowed to stand for 1-48 h to obtain a seed source solution containing metal oxide and alkali.

[0026] Preferably, the amount of the metal oxide is 0.5 mol, the amount of the alkali is 0.5 mol, the stirring speed is 500 r / min, the stirring time is 30 min, and the standing time is 24 h.

[0027] In the preparation method described above, the temperature of the hydrothermal reaction in step (4) is 1 to 180°C, and the time of the hydrothermal reaction is 1 to 24 hours.

[0028] Preferably, the hydrothermal reaction temperature is 90℃ and the hydrothermal reaction time is 12h;

[0029] The metal oxide is selected from at least one of AgNO3, Al(NO3)3, Zn(NO3)2, Zn(NO3)2·6H2O, Zn(CH3COO)2·2H2O, ZnSO4·7H2O, SnCl2·2H2O, SnCl4, NiSO4, Mg(NO3)2, Ni(CH3COO)2 and FeSO4;

[0030] The crystallization regulator is selected from at least one of polyethylene glycol, polyacrylic acid, hexamethylenetetramine, cyclohexylamine, ethylenediamine, and ethanolamine;

[0031] The preparation process of the growth solution is as follows: 0.001-0.05 mol of metal oxide and 0.001-0.05 mol of crystallization regulator are dissolved in 1-100 mL of deionized water, and the pH is adjusted to 7-9 using a pH adjuster to obtain a growth solution containing metal oxide and crystallization regulator.

[0032] Preferably, the amount of the metal oxide is 0.015 mol, the amount of the crystallization regulator is 0.015 mol, and the pH regulator is selected from at least one of KOH, NaOH, and ammonia water.

[0033] In the preparation method described above, the aldehyde compound in step (5) is selected from any one of furfural, paraformaldehyde, formaldehyde, and acetaldehyde;

[0034] Preferably, the aldehyde compound is one of formaldehyde and acetaldehyde;

[0035] The phenolic compound is selected from any one of cresol, xylenol, tert-butylphenol, bisphenol A, p-aminophenol, p-acetaminophenol, and resorcinol;

[0036] Preferably, the phenolic compound is any one of aminophenol, acetaminophen, and resorcinol;

[0037] The water bath temperature for the polymerization reaction is 25–40°C; the polymerization reaction time is 1–24 h.

[0038] In the preparation method described above, the inert gas in step (6) is one of helium, argon and nitrogen; the heating rate is 5℃ / min; the pyrolysis treatment temperature is 600~900℃ and the time is 2h.

[0039] Preferably, the inert gas is argon; the pyrolysis temperature is 700°C.

[0040] In the preparation method described above, the drying temperature in step (7) is 50–100°C; the acid is selected from at least one of sulfuric acid, nitric acid, and hydrochloric acid.

[0041] Preferably, the acid is 1 mol / L hydrochloric acid.

[0042] In a second aspect, the present invention provides a carbon-based negative electrode current collector with a lithiophilic confined structure, which is prepared by the method described in any one of claims 1-8.

[0043] Thirdly, the present invention provides the application of the carbon-based negative electrode current collector with the described lithium-philic confined structure in the preparation of lithium metal batteries or negative electrode-free lithium metal batteries.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. In the carbon-based negative electrode current collector with a lithiophilic confined structure of the present invention, the lithiophilic metal oxide can induce lithium metal to preferentially deposit in the nanotube structure and reduce the overpotential. After the lithium metal fills the inside of the nanotube structure, the top becomes rounded, providing seed crystals for subsequent lithium deposition. The lithium metal will then be deposited on the outside of the tubular structure and between the tubular structures. By controlling the lithium deposition morphology, the growth of lithium dendrites is restricted, preventing dendrites from piercing the separator and improving battery safety.

[0046] 2. The nanostructure not only provides a sufficiently large specific surface area and ion diffusion channels, improving conductivity and accelerating and stabilizing the formation of the SEI film, but also the high specific surface area of ​​the three-dimensional carbon fiber skeleton can adapt to volume changes during charging and discharging and effectively reduce local current density, thereby ensuring uniform lithium deposition and improving battery safety and cycle stability.

[0047] 3. The battery assembled using the three-dimensional carbon-based current collector of this invention achieves a current-to-air ratio of 1 mA / cm². 2 Current density and 4mAh / cm 2 With a certain amount of sediment, the average coulombic efficiency can still reach about 99.53% after 100 cycles, demonstrating good cycle stability.

[0048] 4. This invention enables the large-scale, controllable production of high-quality current collectors. Surface modification of the current collector can improve the cycle stability of the battery, which is of great significance for applications in energy storage and electrochemical energy technologies. The production equipment for this invention is simple, quick, and effectively saves costs. Attached Figure Description

[0049] Figure 1 The flowchart shows the preparation process of the carbon-based negative electrode current collector with a lithiophilic confined structure in Examples 1-5.

[0050] Figure 2 SEM image of the carbon-coated zinc oxide carbon cloth prepared in Example 1;

[0051] Figure 3SEM image of the carbon-based negative electrode current collector with a lithiophilic confined structure prepared in Example 1;

[0052] Figure 4 XRD pattern of the carbon-based negative electrode current collector with a lithiophilic confined structure prepared in Example 1;

[0053] Figure 5 The cycle efficiency diagram shows the carbon-based negative electrode current collector (C@ZnO@CC) with a lithiophilic confined structure prepared in Example 1. Detailed Implementation

[0054] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0055] Example 1:

[0056] The preparation flowchart of the carbon-based anode current collector with a lithiophilic confinement structure in this embodiment is shown below. Figure 1 The specific process is as follows:

[0057] (1) Surface activation treatment of carbon substrate

[0058] Carbon cloth cut to 4mm×4mm was ultrasonically treated in acetone, ethanol, and deionized water for 10 minutes in sequence. Then, the carbon cloth was placed in a concentrated acid mixture with a volume ratio of H2SO4:HNO3 = 3:1 (V:V), heated in a water bath at 40℃ for 4 hours to activate it and provide uniform growth sites for the growth of metal oxides. After removal, it was dried at 80℃.

[0059] (2) Impregnate the carbon substrate with a metal oxide seed layer

[0060] Dissolve 0.5 mol Zn(CH3COO)2·2H2O in 50 mL of anhydrous ethanol and 0.5 mol NaOH in 50 mL of anhydrous ethanol, mix them, stir magnetically at 500 r / min for 30 min, let stand for 12 h to obtain the seed crystal source solution. The process of impregnating the seed crystal layer is to soak carbon cloth in the seed crystal source solution for 10 min, take it out and dry it in an oven at 90℃, and repeat the impregnation 3 times.

[0061] (3) Growth of lithium-loving metal oxides on carbon substrate surface

[0062] 0.015 mol Zn(NO3)2·6H2O and 0.015 mol hexamethylenetetramine were dissolved in 90 mL of deionized water, and the pH was adjusted to 9 with ammonia to obtain a zinc oxide growth solution. Carbon cloth was immersed in the growth solution, and the reaction was carried out at a hydrothermal temperature of 90℃ for 12 h. Carbon cloth with zinc oxide grown on its surface was obtained using a hydrothermal method. Figure 2 The image shows a SEM image of carbon-coated zinc oxide carbon cloth, which reveals that the surface of the carbon fibers is uniformly covered by carbon-coated ZnO nanorods.

[0063] (4) Preparation of carbon-based negative electrode current collector with lithiophilic confinement structure

[0064] 10 mL of 25 wt% ammonia solution was added to 70 mL of ethanol and 10 mL of deionized water to obtain a mixed solution; 0.7 g of resorcinol was added and magnetically stirred for 10 min; 0.5 mL of 37 wt% formaldehyde solution was added; the carbon substrate obtained in step (4) was placed into the above mixed solution; the mixture was heated in a water bath at 30 °C for 12 hours and then the carbon substrate was removed; after drying, it was placed in a tube furnace, argon gas was introduced, and the temperature was increased to 750 °C at a rate of 5 °C / min for 2 h to pyrolyze the mixture, resulting in a carbon-coated zinc oxide nanorod carbon cloth current collector; the carbon cloth current collector obtained above was cooled, placed in 1 mol / L hydrochloric acid for 5 s to etch away some of the zinc oxide, washed until neutral, and dried to obtain a carbon-based negative electrode current collector with a lithiophilic confined structure. Figure 3 The image shows a SEM image of a carbon-based negative electrode current collector with a lithiophilic confined structure. The morphology is completely preserved after partial etching of ZnO with hydrochloric acid. Figure 4 The XRD pattern of the carbon-based negative electrode current collector with a lithium-loving confined structure is shown. The C@ZnO@CC peaks are sharp, and it can be clearly seen that the growth is oriented in the direction perpendicular to the (101) crystal plane. All the peak positions are consistent with PDF card 36-1451.

[0065] The carbon-based negative electrode current collector with a lithiophilic confined structure was cut into electrode sheets with a diameter of 12 mm using a cutting machine. Lithium sheets were used as the counter electrode, 1M LiTFSI (solvent: 1,3-dioxolane (DOL): ethylene glycol dimethyl ether (DME) volume ratio 1:1, 2 wt.% LiNO3 as additive) as the electrolyte, and a porous monolayer polypropylene membrane as the separator. A 2032-type button cell was assembled in a glove box (high-purity argon atmosphere, where the O2 and H2O contents are both less than 0.1 ppm). The results are as follows: Figure 5 The diagram shows the cycle efficiency of a carbon-based anode current collector (C@ZnO@CC) with a lithiophilic confined structure. At 1 mA / cm²... 2 Tested at a current density, the average coulombic efficiency reached 99.53% after 100 long-cycle tests, which is better than the original carbon cloth in both coulombic efficiency and cycle performance.

[0066] Example 2:

[0067] The preparation flowchart of the carbon-based anode current collector with a lithiophilic confinement structure in this embodiment is shown below. Figure 1 The specific process is as follows:

[0068] (1) Surface activation treatment of carbon substrate

[0069] Carbon cloth cut to 4mm×4mm was ultrasonically treated in acetone, ethanol, and deionized water for 5 minutes each. Then, the carbon cloth was placed in a mixture of concentrated sulfuric acid (AR) and concentrated nitric acid (AR) with a volume ratio of H2SO4:HNO3 = 3:1 (V:V), heated in a water bath at 30℃ for 4 hours to activate it and provide uniform growth sites for the growth of metal oxides. After removal, it was dried at 80℃.

[0070] (2) Impregnate the carbon substrate with a metal oxide seed layer

[0071] Dissolve 0.5 mol Zn(CH3COO)2·2H2O in 50 mL of anhydrous ethanol and 0.5 mol NaOH in 50 mL of anhydrous ethanol, mix them, stir magnetically at 500 r / min for 30 min, let stand for 10 h to obtain the seed crystal source solution. The process of impregnating the seed crystal layer is to soak carbon cloth in the seed crystal source solution for 10 min, take it out and dry it in an oven at 90℃, and repeat the impregnation 3 times.

[0072] (3) Growth of lithium-loving metal oxides on carbon substrate surface

[0073] 0.01 mol Zn(NO3)2·6H2O and 0.01 mol hexamethylenetetramine were dissolved in 90 mL of deionized water, and the pH was adjusted to 7 with ammonia to obtain a zinc oxide growth solution. Carbon cloth was immersed in the growth solution, and the hydrothermal temperature was 90℃ for 12 h. Carbon cloth with zinc oxide grown on its surface was obtained by hydrothermal method.

[0074] (4) Preparation of carbon-based negative electrode current collector with lithiophilic confinement structure

[0075] Add 5 mL of 25 wt% ammonia water to 75 mL of ethanol and 10 mL of deionized water to obtain a mixed solution; add 0.5 g of resorcinol and stir magnetically for 10 min; add 0.5 mL of 37 wt% formaldehyde solution; place the carbon substrate obtained in step (4) into the above mixed solution; heat in a water bath at 30 °C; react for 12 hours and then remove the carbon substrate; dry it and place it in a tube furnace; introduce argon gas; heat to 750 °C at a rate of 5 °C / min and react for 2 h to pyrolyze it to obtain a carbon-coated zinc oxide nanorod carbon cloth current collector; place the carbon cloth current collector obtained above into 1 mol / L hydrochloric acid for 30 s; cool it; etch away some of the zinc oxide; wash it until neutral; dry it to obtain a carbon-based negative electrode current collector with a lithium-philic confined structure.

[0076] At 1mA / cm 2 Tested at a current density, the average coulombic efficiency reached 99.13% after 100 long-cycle tests.

[0077] Example 3:

[0078] The preparation flowchart of the carbon-based anode current collector with a lithiophilic confinement structure in this embodiment is shown below. Figure 1 The specific process is as follows:

[0079] (1) Surface activation treatment of carbon substrate

[0080] Carbon cloth cut to 4mm×4mm was ultrasonically treated in acetone, ethanol, and deionized water for 10 minutes each. Then, the carbon cloth was placed in a mixture of concentrated sulfuric acid (AR) and concentrated nitric acid (AR) with a volume ratio of H2SO4:HNO3 = 1:1 (V:V), heated in a water bath at 30℃ for 2 hours to activate it and provide uniform growth sites for the growth of metal oxides. After removal, it was dried at 80℃.

[0081] (2) Impregnate the carbon substrate with a metal oxide seed layer

[0082] Dissolve 0.3 mol Zn(CH3COO)2·2H2O in 50 mL of anhydrous ethanol and 0.3 mol NaOH in 50 mL of anhydrous ethanol, mix them, stir magnetically at 500 r / min for 30 min, and let stand for 12 h to obtain the seed crystal source solution. The process of impregnating the seed crystal layer is to soak the carbon cloth in the seed crystal source solution for 5 min, take it out and dry it in an oven at 90℃, and repeat the impregnation 3 times.

[0083] (3) Growth of lithium-loving metal oxides on carbon substrate surface

[0084] 0.008 mol Zn(NO3)2·6H2O and 0.008 mol hexamethylenetetramine were dissolved in 90 mL of deionized water, and the pH was adjusted to 9 with ammonia to obtain a zinc oxide growth solution. Carbon cloth was immersed in the growth solution, and the hydrothermal temperature was 90℃ for 10 h. Carbon cloth with zinc oxide grown on its surface was obtained by hydrothermal method.

[0085] (4) Preparation of carbon-based negative electrode current collector with lithiophilic confinement structure

[0086] 20 mL of 25 wt% ammonia solution was added to 60 mL of ethanol and 10 mL of deionized water to obtain a mixed solution; 0.6 g of resorcinol was added and magnetically stirred for 10 min; 0.4 mL of 37 wt% formaldehyde solution was added; the carbon substrate obtained in step (4) was placed into the above mixed solution; the mixture was heated in a water bath at 30 °C and reacted for 12 hours; the carbon substrate was then removed; after drying, it was placed in a tube furnace, argon gas was introduced, and the temperature was increased to 700 °C at a rate of 5 °C / min for 2 h to pyrolyze the mixture, resulting in a carbon-coated zinc oxide nanorod carbon cloth current collector; the carbon cloth current collector obtained above was placed in 1 mol / L hydrochloric acid for 20 s, cooled, and partially etched away the zinc oxide; it was washed until neutral and dried to obtain a carbon-based negative electrode current collector with a lithiophilic confined structure.

[0087] At 1mA / cm 2 Tested at a current density, the average coulombic efficiency reached 99.27% ​​after 100 long-cycle tests.

[0088] Example 4:

[0089] The preparation flowchart of the carbon-based anode current collector with a lithiophilic confinement structure in this embodiment is shown below. Figure 1 The specific process is as follows:

[0090] (1) Surface activation treatment of carbon substrate

[0091] Carbon cloth cut to 4mm×4mm was ultrasonically treated in acetone, ethanol, and deionized water for 10 minutes in sequence. Then, the carbon cloth was placed in a concentrated acid mixture with a volume ratio of H2SO4:HNO3 = 2:1 (V:V), heated in a water bath at 30℃ for 1 hour to activate it and provide uniform growth sites for the growth of metal oxides. After removal, it was dried at 80℃.

[0092] (2) Impregnate the carbon substrate with a metal oxide seed layer

[0093] 0.25 mol Zn(CH3COO)2·2H2O was dissolved in anhydrous ethanol and 0.25 mol NaOH was dissolved in anhydrous ethanol. The mixture was stirred magnetically at 500 r / min for 20 min and allowed to stand for 10 h to obtain the seed crystal source solution. The process of impregnating the seed crystal layer was to soak carbon cloth in the seed crystal source solution for 20 min, take it out and dry it in an oven at 85 ℃. This impregnation was repeated 3 times.

[0094] (3) Growth of lithium-loving metal oxides on carbon substrate surface

[0095] 0.005 mol Zn(NO3)2·6H2O and 0.005 mol hexamethylenetetramine were dissolved in 80 mL of deionized water, and the pH was adjusted to 9 with ammonia to obtain a zinc oxide growth solution. Carbon cloth was immersed in the growth solution, and the hydrothermal temperature was 90℃ for 8 h. Carbon cloth with zinc oxide grown on its surface was obtained by hydrothermal method.

[0096] (4) Preparation of carbon-based negative electrode current collector with lithiophilic confinement structure

[0097] 15 mL of 25 wt% ammonia solution was added to 60 mL of ethanol and 15 mL of deionized water to obtain a mixed solution; 0.5 g of resorcinol was added and magnetically stirred for 10 min; 0.5 mL of 37 wt% formaldehyde solution was added; the carbon substrate obtained in step (4) was placed into the above mixed solution; the mixture was heated in a water bath at 30 °C and reacted for 10 hours; the carbon substrate was then removed; after drying, it was placed in a tube furnace, argon gas was introduced, and the temperature was raised to 850 °C at a rate of 5 °C / min for 2 h to pyrolyze the mixture, thereby obtaining a carbon-coated zinc oxide nanorod carbon cloth current collector; the carbon cloth current collector obtained above was placed in 1 mol / L hydrochloric acid for 15 s, cooled, and partially etched away the zinc oxide; it was washed until neutral and dried to obtain a carbon-based negative electrode current collector with a lithium-philic confined structure.

[0098] At 1mA / cm 2 Tested at a current density, the average coulombic efficiency reached 99.31% after 100 long-cycle tests.

[0099] Example 5:

[0100] The preparation flowchart of the carbon-based negative electrode current collector with a lithiophilic confinement structure in this embodiment is shown below. Figure 1 The specific process is as follows:

[0101] (1) Surface activation treatment of carbon substrate

[0102] Carbon cloth cut to 4mm×4mm was ultrasonically treated in acetone, ethanol, and deionized water for 5 minutes in sequence. Then, the carbon cloth was placed in a concentrated acid mixture with a volume ratio of H2SO4:HNO3 = 4:1 (V:V), heated in a water bath at 40℃ for 2 hours to activate it and provide uniform growth sites for the growth of metal oxides. After removal, it was dried at 80℃.

[0103] (2) Impregnate the carbon substrate with a metal oxide seed layer

[0104] 0.25 mol Zn(CH3COO)2·2H2O was dissolved in anhydrous ethanol and 0.25 mol NaOH was dissolved in anhydrous ethanol. The mixture was stirred magnetically at 500 r / min for 10 min and allowed to stand for 5 h to obtain the seed crystal source solution. The process of impregnating the seed crystal layer was to soak the carbon cloth in the seed crystal source solution for 5 min, take it out and dry it in an oven at 90 ℃. This impregnation was repeated 3 times.

[0105] (3) Growth of lithium-loving metal oxides on carbon substrate surface

[0106] 0.015 mol Zn(NO3)2·6H2O and 0.015 mol hexamethylenetetramine were dissolved in 80 mL of deionized water, and the pH was adjusted to 9 with ammonia water to obtain a zinc oxide growth solution. Carbon cloth was immersed in the growth solution, and the hydrothermal temperature was 90℃ for 10 h. Carbon cloth with zinc oxide grown on its surface was obtained by hydrothermal method.

[0107] (4) Carbon-based negative electrode current collector with a lithiophilic confinement structure

[0108] 10 mL of 25 wt% ammonia solution was added to 70 mL of ethanol and 10 mL of deionized water to obtain a mixed solution; 0.7 g of resorcinol was added and magnetically stirred for 10 min; 0.6 mL of 37 wt% formaldehyde solution was added; the carbon substrate obtained in step (4) was placed into the above mixed solution; the mixture was heated in a water bath at 30 °C and reacted for 8 hours; the carbon substrate was then removed; after drying, it was placed in a tube furnace, argon gas was introduced, and the temperature was increased to 700 °C at a rate of 5 °C / min for 2 h to pyrolyze the mixture, resulting in a carbon-coated zinc oxide nanorod carbon cloth current collector; the carbon cloth current collector obtained above was placed in 1 mol / L hydrochloric acid for 40 s, cooled, and partially etched away the zinc oxide; it was washed until neutral and dried to obtain a carbon-based negative electrode current collector with a lithiophilic confined structure.

[0109] At 1mA / cm 2 Tested at a current density, the average coulombic efficiency reached 99.32% after 100 long-cycle tests.

[0110] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a carbon-based negative electrode current collector with a lithiophilic confined structure, characterized in that, Includes the following steps: (1) Take a carbon substrate and clean the slurry on the surface; (2) The carbon substrate cleaned in step (1) is placed in a concentrated acid solution, activated by water bath heating, and then dried; (3) The carbon substrate activated in step (2) is immersed in a seed source solution containing metal oxide precursor and alkali, then dried and repeatedly immersed. (4) Immerse the carbon substrate obtained in step (3) in a growth solution containing metal oxide precursor and crystallization regulator to carry out hydrothermal reaction to grow metal oxide on the carbon substrate, and then wash and dry it. (5) Using the carbon substrate obtained in step (4) as a template, aldehyde compounds and phenolic compounds are added and polymerized in a mixed solution of ammonia, ethanol and deionized water. After drying, a carbon precursor-coated metal oxide carbon substrate is obtained. (6) The carbon precursor-coated metal oxide carbon substrate is heated to the pyrolysis temperature under an inert atmosphere to perform pyrolysis treatment to obtain the carbon-coated metal oxide carbon substrate. (7) Cool, then etch some of the metal oxides with acid, wash until neutral, dry, and obtain a carbon-based negative electrode current collector with a lithium-loving confined structure; The metal oxide precursor is selected from at least one of AgNO3, Al(NO3)3, Zn(NO3)2, Zn(NO3)2·6H2O, Zn(CH3COO)2·2H2O, ZnSO4·7H2O, SnCl2·2H2O, SnCl4, NiSO4, Mg(NO3)2, Ni(CH3COO)2, and FeSO4.

2. The preparation method according to claim 1, characterized in that, The carbon substrate mentioned in step (1) can be any one of carbon cloth, carbon paper, graphene, and carbon nanotubes; The cleaning method includes: ultrasonic cleaning in acetone, ethanol and deionized water in sequence; The drying temperature is 25~100℃.

3. The preparation method according to claim 2, characterized in that, The drying temperature is 80 ℃.

4. The preparation method according to claim 1, characterized in that, The concentrated acid solution in step (2) is any two or more of concentrated sulfuric acid AR, concentrated nitric acid AR, and concentrated hydrochloric acid AR; the water bath heating time is 0.5~10h and the temperature is 25~50℃; the drying temperature is 60~90℃.

5. The preparation method according to claim 4, characterized in that, The concentrated acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, wherein the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 1~5:

1.

6. The preparation method according to claim 5, characterized in that, The volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:

1. The water bath heating time is 4 hours; The water bath heating temperature is 30°C; The drying temperature is 80°C.

7. The preparation method according to claim 1, characterized in that, The soaking time in step (3) is 1~30 min, the drying temperature is 25~100℃, and the number of soaking times is 1~5. The alkali is selected from at least one of KOH, NaOH and ammonia water; The preparation process of the seed source solution is as follows: 0.1~1 mol of anhydrous ethanol solution of metal oxide precursor is mixed with 0.1~1 mol of anhydrous ethanol solution of alkali, stirred at 1~1000 r / min for 1~60 min, and then allowed to stand for 1~48 h to obtain a seed source solution containing metal oxide precursor and alkali.

8. The preparation method according to claim 7, characterized in that, The soaking time is 10 minutes, and the drying temperature is 90℃; the soaking is repeated 3 times. The amount of the metal oxide precursor is 0.5 mol, and the amount of the base is 0.5 mol; the stirring speed is 500 r / min, the stirring time is 30 min, and the standing time is 24 h.

9. The preparation method according to claim 1, characterized in that, The temperature of the hydrothermal reaction in step (4) is 1~180℃, and the time of the hydrothermal reaction is 1~24h; The crystallization regulator is selected from at least one of polyethylene glycol, polyacrylic acid, hexamethylenetetramine, cyclohexylamine, ethylenediamine, and ethanolamine; The preparation process of the growth solution is as follows: 0.001~0.05 mol of metal oxide precursor and 0.001~0.05 mol of crystallization regulator are dissolved in 1~100 mL of deionized water, and the pH is adjusted to 7-9 using a pH adjuster to obtain a growth solution containing metal oxide precursor and crystallization regulator.

10. The preparation method according to claim 9, characterized in that, The hydrothermal reaction temperature was 90℃, and the hydrothermal reaction time was 12 hours. The amount of the metal oxide precursor is 0.015 mol, the amount of the crystallization regulator is 0.015 mol, and the pH regulator is selected from at least one of KOH, NaOH and ammonia water.

11. The preparation method according to claim 1, characterized in that, The volume-to-mass ratio of the aldehydes, phenols, ethanol, deionized water and ammonia in step (5) is 0.05-1 mL: 0.05-1 g: 1-100 mL: 1-50 mL: 1-50 mL; The aldehyde compounds are selected from any one of furfural, paraformaldehyde, formaldehyde, and acetaldehyde; The phenolic compound is selected from any one of cresol, xylenol, tert-butylphenol, bisphenol A, p-aminophenol, p-acetaminophenol, and resorcinol; The water bath temperature for the polymerization reaction is 25~40℃; the polymerization reaction time is 1~24h.

12. The preparation method according to claim 11, characterized in that, The aldehyde compound is one of formaldehyde and acetaldehyde; The phenolic compound is any one of aminophenol, acetaminophenol, and resorcinol.

13. The preparation method according to claim 1, characterized in that, The inert atmosphere in step (6) is one of helium, argon and nitrogen; the heating rate is 5℃ / min; the temperature of the pyrolysis treatment is 600~900℃ and the time is 2h.

14. The preparation method according to claim 13, characterized in that, The inert atmosphere is argon; the pyrolysis temperature is 750℃.

15. The preparation method according to claim 1, characterized in that, The drying temperature in step (7) is 50~100℃; the acid is selected from at least one of sulfuric acid, nitric acid and hydrochloric acid.

16. The preparation method according to claim 1, characterized in that, The acid is 1 mol / L hydrochloric acid.

17. A carbon-based negative electrode current collector with a lithiophilic confined structure, characterized in that, It is prepared by the method according to any one of claims 1-16.

18. The application of the carbon-based negative electrode current collector with a lithiophilic confined structure as described in claim 17 in the preparation of lithium metal batteries or negative electrode-free lithium metal batteries.

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