Zinc-containing current collector and preparation method thereof, negative electrode and negative-electrode-free lithium metal battery

Abstract

The invention relates to a zinc-containing current collector and a preparation method thereof, a negative electrode and a negative-electrode-free lithium metal battery, and the method comprises the following steps: carrying out heat treatment on zinc oxide powder, ammonia gas and a current collector matrix at a set temperature, so that the zinc oxide powder and the ammonia gas are subjected to a chemical reaction to generate zinc, and the zinc is attached to at least part of the surface of the current collector substrate to obtain the zinc-containing current collector. Zn in the current collector has lithium affinity and can strongly adsorb lithium ions, so that the distribution of the lithium ions on a negative electrode is more uniform, and the lithium ions can be more orderly deposited on the surface of the current collector in the charging process; the zinc can enable the charge distribution to be more uniform, so that the non-uniform deposition of lithium ions and the formation of lithium dendrites caused by the non-uniform charge are reduced; the current collector can promote formation of SEI rich in Li-Zn alloy phase, so that lithium ions are guided to uniformly penetrate through an SEI film and deposit on a negative electrode, and meanwhile, further decomposition of electrolyte and growth of lithium dendrites can be inhibited.

Description

Technical Field

[0001] The present application relates to the technical field of lithium metal batteries, and in particular to a zinc-containing current collector and a preparation method thereof, a negative electrode, and a negative electrode-free lithium metal battery. Background Art

[0002] Lithium-ion batteries have attracted much attention due to their excellent and stable electrochemical performance. However, the traditional negative electrode material (graphite) limits the energy density of lithium-ion batteries. -1 ), low potential voltage (-3.04V vsRHE) and high energy density lithium metal anode (negative electrode) (LMAs) are expected to be ideal anode materials. However, the energy storage of LMAs depends on the stripping / deposition of Li+ on the anode. However, the growth of deposited lithium often cannot maintain density and uniformity, and Li + The uneven deposition of Li leads to the formation of Li dendrites, and the “tip effect” enhances the electric field and attracts the surrounding Li + , promoting the growth of dendrites.

[0003] At present, negative electrode-free lithium metal batteries can well balance safety and high energy density. However, during the charging process of negative electrode-free lithium metal batteries, lithium ions combine with electrons on the surface of the negative electrode current collector. During the lithium ion deposition process, due to its low lattice matching with the matrix material (poor lithium affinity), it has a high nucleation barrier, making it difficult for lithium ions to be deposited uniformly and densely on the matrix material. Therefore, it is urgent to explore a current collector that can adjust the lithium metal deposition layer and has high mechanical-electrochemical stability. Summary of the invention

[0004] The present application provides a zinc-containing current collector and a preparation method thereof, a negative electrode, and a negative electrode-free lithium metal battery to solve the following technical problem: how to reduce the lithium dendrite phenomenon during the lithium deposition process.

[0005] In a first aspect, the present application provides a method for preparing a zinc-containing current collector, the method comprising:

[0006] Under a set temperature, the zinc oxide powder, ammonia and the current collector matrix are heat treated so that the zinc oxide powder and the ammonia react chemically to generate zinc, and the zinc adheres to at least a portion of the surface of the current collector matrix to obtain a zinc-containing current collector.

[0007] Optionally, the set temperature is 400°C to 900°C.

[0008] Optionally, the heat treatment time is 0.5h to 1.5h.

[0009] Optionally, the weight of the zinc oxide powder is 2 mg to 10 mg, and the volume fraction of the ammonia gas is 5% to 10%.

[0010] Optionally, the temperature is raised to the set temperature at a set heating rate, and the set heating rate is 5°C / min to 10°C

[0011] / min.

[0012] Optionally, the current collector includes a three-dimensional foam carbon current collector.

[0013] In a second aspect, the present application provides a zinc-containing current collector, which is prepared by the method described in any one of the first aspects.

[0014] In a third aspect, the present application provides a negative electrode, comprising the zinc-containing current collector as described in any one of the second aspects.

[0015] Optionally, the negative electrode is obtained by immersing the zinc-containing current collector in molten metallic lithium.

[0016] In a fourth aspect, the present application provides a negative electrode-free lithium metal battery, wherein the lithium metal battery comprises the negative electrode described in any one of the third aspects.

[0017] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0018] The preparation method of the zinc-containing current collector provided in the embodiment of the present application comprises: under the condition of a set temperature, heat-treating zinc oxide powder, ammonia gas and a current collector matrix, so that the zinc oxide powder reacts chemically with the ammonia gas to generate zinc, and the zinc is attached to at least part of the surface of the current collector matrix, thereby obtaining a zinc-containing current collector. Under the condition of a set temperature, the zinc oxide powder reacts chemically with the ammonia gas through heat treatment to generate zinc, and the zinc can be deposited on the surface of the current collector and attached to the surface of the current collector; the Zn in the current collector has lithium affinity and can strongly adsorb lithium ions, so that the distribution of lithium ions on the negative electrode can be more uniform, and during the charging process, the lithium ions can be deposited on the surface of the current collector in a more orderly manner; and zinc can make the charge distribution more uniform, thereby reducing the uneven deposition of lithium ions and the formation of lithium dendrites caused by uneven charge; the current collector can promote the formation of SEI rich in Li-Zn alloy phase, thereby guiding lithium ions to uniformly pass through the SEI film and deposit on the negative electrode, and can also inhibit the further decomposition of the electrolyte and the growth of lithium dendrites. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0020] In order to more clearly illustrate the embodiments of the present application 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Figure 1 A schematic flow chart of a method for preparing a zinc-containing current collector provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0024] In this application, unless otherwise specified, directional words such as "upper" and "lower" used refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of this application, the terms "include", "comprise", etc. mean "including but not limited to".

[0025] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0026] In a first aspect, the present application provides a method for preparing a zinc-containing current collector. Figure 1 A schematic diagram of a process for preparing a zinc-containing current collector provided in an embodiment of the present application; see Figure 1 , the method comprising:

[0027] S1. Under the condition of set temperature, zinc oxide (ZnO) powder and ammonia (NH 3 ) and a current collector (NF) are heat-treated so that the zinc oxide powder reacts chemically with the ammonia gas to generate zinc, and the zinc adheres to at least a portion of the surface of the current collector matrix to obtain a zinc-containing current collector.

[0028] In the implementation of the present application, under the condition of a set temperature, zinc oxide powder and ammonia react chemically through heat treatment to generate zinc, and the zinc can be deposited on the surface of the current collector and attached to the surface of the current collector; the Zn in the current collector has a lithium affinity and can strongly adsorb lithium ions, which can make the distribution of lithium ions on the negative electrode more uniform. During the charging process, lithium ions can be deposited on the surface of the current collector more orderly. The lithium-philic zinc can change the nucleation overpotential of lithium, making the nucleation of lithium easier and more uniform, and avoiding the growth of lithium dendrites caused by excessive local overpotential; zinc can The charge distribution is made more uniform, thereby reducing the uneven deposition of lithium ions and the formation of lithium dendrites caused by uneven charge; the current collector can promote the formation of SEI rich in Li-Zn alloy phase, thereby guiding lithium ions to evenly pass through the SEI film and deposit on the negative electrode, while also inhibiting the further decomposition of the electrolyte and the growth of lithium dendrites; zinc can improve the mechanical strength and flexibility of the SEI film, so that it can better adapt to the volume change of lithium ions during the charging and discharging process, reduce the rupture and repair process of the SEI film, and thus reduce the possibility of lithium dendrite formation. And to a certain extent, zinc can also inhibit side reactions, and can provide a more stable environment for the uniform deposition of lithium ions.

[0029] In some embodiments, the set temperature is 400°C to 900°C.

[0030] In some embodiments, the heat treatment time is 0.5 h to 1.5 h.

[0031] In the embodiment of the present application, the "set temperature" refers to the temperature of the heat treatment, which can be 400°C to 900°C, which can fully allow the ZnO powder to react with the NH 3 Can undergo chemical reaction, the chemical reaction is: ZnO+NH 3 =Zn+N 2 +H 2 If the heat treatment temperature is lower than 400℃, the ZnO powder can react with NH 3 If the heat treatment temperature is higher than 900℃, it will cause ZnO powder to react with NH 3The reaction is rapid and violent, and it is difficult to precipitate on the surface of the current collector, and it may even destroy the structure of the current collector. Exemplarily, the above-mentioned set temperature can be 400℃, 430℃, 450℃, 480℃, 500℃, 530℃, 550℃, 580℃, 600℃, 630℃, 650℃, 680℃, 700℃, 730℃, 750℃, 780℃, 800℃, 830℃, 850℃, 870℃, 900℃, etc. The set temperature matches the heat treatment time, which can be 0.5h to 1.5h, giving ZnO powder and NH 3 If the time is too long and exceeds 1.5h, the structure of the three-dimensional carbon foam may be destroyed to a certain extent; if the time is too short and is less than 0.5h, it is difficult to make the ZnO powder and NH 3 For example, the heat treatment time may be 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1.0 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, etc. Further, the set temperature may be 600° C., and the heat treatment time may be 1.5 h.

[0032] In some embodiments, the weight of the zinc oxide powder is 2 mg to 10 mg, and the volume fraction of the ammonia gas is 5% to 10%.

[0033] In the embodiment of the present application, the weight of the zinc oxide powder can be 2 mg to 10 mg, and the volume fraction of ammonia can be 5% to 10%, which can fully allow the ZnO powder to react with NH 3 Can react chemically and regulate the ZnO powder to react with NH 3 The reaction rate is increased so that zinc is uniformly deposited on the surface of the current collector. For example, the weight of the zinc oxide powder can be 2 mg, 3 mg, 4 mg, 5 mg, 6 mg, 7 mg, 8 mg, 9 mg, 10 mg, etc.; the volume fraction of ammonia can be 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0034] In some embodiments, the temperature is increased to the set temperature at a set heating rate, and the set heating rate is 5° C. / min to 10° C. / min.

[0035] In the embodiment of the present application, the temperature is raised to the set temperature at a set heating rate, and the set heating rate can be 5°C.

[0036] / min~10℃ / min, the ZnO powder can be adjusted to react with NH 3 For example, the set heating rate may be 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, etc.

[0037] Specifically, the preparation method of the zinc-containing current collector may include: adding 5.0 mg of ZnO powder into a crucible and placing the cut NF current collector on it; transferring the crucible to a tube furnace and heating it in 5% NH 3 / Ar atmosphere, the temperature was raised to 600°C at a heating rate of 10°C / min and the reaction was carried out for 1.5h; after naturally cooling to room temperature, the Zn@NF current collector was prepared.

[0038] In some embodiments, the current collector comprises a three-dimensional carbon foam current collector.

[0039] In an embodiment of the present application, the above-mentioned current collector can be a three-dimensional foam carbon current collector, which is a carbonaceous current collector with a three-dimensional porous structure, high porosity and three-dimensional structure, and exhibits excellent conductivity, good mechanical stability and outstanding chemical stability. The three-dimensional foam carbon current collector has excellent temperature resistance, so that the structure of the three-dimensional foam carbon current collector is not easily destroyed during the above-mentioned heat treatment. The zinc-containing current collector is designed into a three-dimensional structure, which can change the electric field distribution at the negative electrode interface. Compared with a planar structure, a current collector with a three-dimensional structure has a larger specific surface area and more pores, which can reduce the local current density, make the distribution of lithium ions on the entire current collector more uniform, and reduce the growth of lithium dendrites caused by excessive local current.

[0040] In a second aspect, the present application provides a zinc-containing current collector, which is prepared by the method described in any one of the first aspects.

[0041] The zinc-containing current collector is realized based on the preparation method of the above-mentioned zinc-containing current collector. The specific steps of the preparation method of the zinc-containing current collector can refer to the above-mentioned embodiment. Since the zinc-containing current collector adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here one by one.

[0042] In a third aspect, the present application provides a negative electrode, comprising the zinc-containing current collector as described in any one of the second aspects.

[0043] In some embodiments, the negative electrode is obtained by immersing the zinc-containing current collector in molten metallic lithium.

[0044] In the embodiment of the present application, the above-mentioned zinc-containing current collector is used to prepare the negative electrode, which can effectively promote the uniform deposition of lithium, thereby avoiding the generation of lithium dendrites and improving the performance of the negative electrode. The negative electrode can be obtained by immersing the zinc-containing current collector in molten metal lithium, and the immersion time can be 5min to 30min, so as to ensure that the molten metal Li fully infiltrates the Zn@NF substrate. The Zn-modified three-dimensional foam carbon can form a stable SEI film to inhibit the growth of lithium dendrites.

[0045] The negative electrode is realized based on the above-mentioned zinc-containing current collector. The specific structure of the zinc-containing current collector can refer to the above-mentioned embodiment. Since the negative electrode adopts part or all of the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0046] In a fourth aspect, the present application provides a negative electrode-free lithium metal battery, wherein the lithium metal battery comprises the negative electrode described in any one of the third aspects.

[0047] In the embodiment of the present application, the negative electrode-free lithium metal battery is a lithium metal battery that does not contain an independent negative electrode material in the traditional sense, and the lithium source required in its working process is completely provided by the positive electrode. The negative electrode-free lithium metal battery has the advantages of high energy density, low cost, easy assembly and compatibility with existing production equipment. The negative electrode-free lithium metal battery contains the above-mentioned negative electrode, which can induce uniform deposition of lithium, while reducing the diffusion barrier during lithium deposition, effectively promoting lithium ion migration, and improving the cycle performance of the negative electrode-free lithium metal battery. Exemplarily, the negative electrode-free lithium metal battery can be a negative electrode-free soft-pack lithium metal battery, and its composition is the same as that of a conventional battery, including components such as a positive electrode sheet, a negative electrode sheet, a diaphragm, an electrolyte, an aluminum-plastic film, and a pole ear. Among them, 1) positive electrode preparation: the positive electrode material is a mixture of one or more of lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), lithium iron phosphate (LFP), lithium cobalt oxide, lithium manganese oxide, and lithium-rich solid solution; the conductive agent is a mixture of one or more of SUPERP, KS-6, single-walled carbon nanotubes, and multi-walled carbon nanotubes; the binder is a mixture of one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, and polyacrylic acid; the solvent is a mixture of one or more of ethanol, N-methylpyrrolidone (NMP), polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol, and polyvinylidene fluoride.

[0048] The negative electrode-free lithium metal battery is realized based on the above-mentioned negative electrode. The specific structure of the negative electrode can refer to the above-mentioned embodiment. Since the negative electrode-free lithium metal battery adopts part or all of the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0049] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0050] Example 1

[0051] (1) A method for preparing a zinc-containing current collector: Under a set temperature, zinc oxide powder, ammonia gas and a current collector matrix are heat-treated so that the zinc oxide powder and ammonia gas react chemically to generate zinc, and the zinc is attached to at least part of the surface of the current collector matrix, thereby obtaining a zinc-containing current collector Zn@NF. The set temperature is 600°C, the heat treatment time is 0.5h, the weight of the zinc oxide powder is 5mg, the heat treatment atmosphere: the volume fraction of ammonia gas is 5%; the temperature is increased to the set temperature at a set heating rate, and the set heating rate is 10°C / min; the current collector is a three-dimensional foam carbon current collector.

[0052] (2) A negative electrode: In a glove box, the zinc-containing current collector Zn@NF was immersed in molten metal Li and taken out after 5 minutes to obtain a ZnZn@NF / Li negative electrode.

[0053] (3) A negative electrode-free lithium metal soft-pack battery: Its components include: positive electrode sheet, negative electrode sheet, separator, electrolyte, aluminum-plastic film, tabs and other components. LFP is used as the positive electrode material and Zn@NF / Li material is used as the negative electrode material. After the electrode sheet is prepared, the above-mentioned electrode sheet and composite separator are stacked in a Z-shaped manner to prepare a 1Ah battery (ZnZn@NF / Li||LFP battery).

[0054] Example 2

[0055] (1) A method for preparing a zinc-containing current collector: Under a set temperature, zinc oxide powder, ammonia gas and a current collector matrix are heat-treated so that the zinc oxide powder and ammonia gas react chemically to generate zinc, and the zinc is attached to at least part of the surface of the current collector matrix, thereby obtaining a zinc-containing current collector Zn@NF. The set temperature is 600°C, the heat treatment time is 1.0h, the weight of the zinc oxide powder is 5mg, the heat treatment atmosphere: the volume fraction of ammonia gas is 5%; the temperature is increased to the set temperature at a set heating rate, and the set heating rate is 10°C / min; the current collector is a three-dimensional carbon foam current collector.

[0056] (2) A negative electrode: In a glove box, the Zn@NF-1 substrate was immersed in molten metal Li and taken out after 5 minutes to obtain a ZnZn@NF / Li negative electrode.

[0057] (3) A negative electrode-free lithium metal soft-pack battery: Its components include: positive electrode sheet, negative electrode sheet, separator, electrolyte, aluminum-plastic film, tabs and other components. LFP is used as the positive electrode material and Zn@NF / Li material is used as the negative electrode material. After the electrode sheet is prepared, the above-mentioned electrode sheet and composite separator are stacked in a Z-shaped manner to prepare a 1Ah battery (ZnZn@NF / Li||LFP battery).

[0058] Example 3

[0059] (1) A method for preparing a zinc-containing current collector: Under a set temperature, zinc oxide powder, ammonia gas and a current collector matrix are heat-treated so that the zinc oxide powder and ammonia gas react chemically to generate zinc, and the zinc is attached to at least part of the surface of the current collector matrix, thereby obtaining a zinc-containing current collector Zn@NF. The set temperature is 600°C, the heat treatment time is 1.5h, the weight of the zinc oxide powder is 5mg, the heat treatment atmosphere: the volume fraction of ammonia gas is 5%; the temperature is increased to the set temperature at a set heating rate, and the set heating rate is 10°C / min; the current collector is a three-dimensional foam carbon current collector.

[0060] (2) A negative electrode: In a glove box, the Zn@NF-1 substrate was immersed in molten metal Li and taken out after 5 minutes to obtain a ZnZn@NF / Li negative electrode.

[0061] (3) A negative electrode-free lithium metal soft-pack battery: Its components include: positive electrode sheet, negative electrode sheet, separator, electrolyte, aluminum-plastic film, tabs and other components. LFP is used as the positive electrode material and Zn@NF / Li material is used as the negative electrode material. After the electrode sheet is prepared, the above-mentioned electrode sheet and composite separator are stacked in a Z-shaped manner to prepare a 1Ah battery (ZnZn@NF / Li||LFP battery).

[0062] Example 4

[0063] (1) A method for preparing a zinc-containing current collector: Under a set temperature, zinc oxide powder, ammonia gas and a current collector matrix are heat-treated so that the zinc oxide powder and ammonia gas react chemically to generate zinc, and the zinc is attached to at least a portion of the surface of the current collector matrix, thereby obtaining a zinc-containing current collector Zn@NF. The set temperature is 400°C, the heat treatment time is 1.0h, the weight of the zinc oxide powder is 5mg, the heat treatment atmosphere: the volume fraction of ammonia gas is 7%; the temperature is increased to the set temperature at a set heating rate, and the set heating rate is 8°C / min; the current collector is a three-dimensional foam carbon current collector.

[0064] (2) A negative electrode: In a glove box, the Zn@NF-1 substrate was immersed in molten metal Li and taken out after 5 minutes to obtain a ZnZn@NF / Li negative electrode.

[0065] (3) A negative electrode-free lithium metal soft-pack battery: Its components include: positive electrode sheet, negative electrode sheet, separator, electrolyte, aluminum-plastic film, tabs and other components. LFP is used as the positive electrode material and Zn@NF / Li material is used as the negative electrode material. After the electrode sheet is prepared, the above-mentioned electrode sheet and composite separator are stacked in a Z-shaped manner to prepare a 1Ah battery (ZnZn@NF / Li||LFP battery).

[0066] Example 5

[0067] (1) A method for preparing a zinc-containing current collector: Under a set temperature, zinc oxide powder, ammonia gas and a current collector matrix are heat-treated so that the zinc oxide powder and ammonia gas react chemically to generate zinc, and the zinc is attached to at least part of the surface of the current collector matrix, thereby obtaining a zinc-containing current collector Zn@NF. The set temperature is 900°C, the heat treatment time is 0.5h, the weight of the zinc oxide powder is 5mg, the heat treatment atmosphere: the volume fraction of ammonia gas is 6%; the temperature is increased to the set temperature at a set heating rate, and the set heating rate is 9°C / min; the current collector is a three-dimensional foam carbon current collector.

[0068] (2) A negative electrode: In a glove box, the Zn@NF-1 substrate was immersed in molten metal Li and taken out after 5 minutes to obtain a NF / Li negative electrode.

[0069] (3) A negative electrode-free lithium metal soft-pack battery: Its components include: positive electrode sheet, negative electrode sheet, separator, electrolyte, aluminum-plastic film, tabs and other components. LFP is used as the positive electrode material and NF / Li negative electrode material is used as the negative electrode material. After the electrode sheet is prepared, the above-mentioned electrode sheet and composite separator are stacked in a Z-shaped manner to prepare a 1Ah battery (ZnZn@NF / Li||LFP battery).

[0070] Comparative Example 1

[0071] (1) A negative electrode: In a glove box, a three-dimensional carbon foam current collector substrate was immersed in molten metal Li and taken out after 5 minutes to obtain a ZnZn@NF / Li negative electrode.

[0072] (2) A negative electrode-free lithium metal soft-pack battery: Its components include: positive electrode sheet, negative electrode sheet, separator, electrolyte, aluminum-plastic film, tabs and other components. LFP is used as the positive electrode material, and Zn@NF-0.5 / Li material is used as the negative electrode material. After the electrode sheet is prepared, the above-mentioned electrode sheet and composite separator are stacked in a Z-shaped manner to prepare a 1Ah battery (ZnZn@NF-0.5 / Li||LFP battery).

[0073] The negative electrode-free lithium metal soft-pack batteries in Examples 1 to 5 and Comparative Example 1 were subjected to 1C charge and discharge cycle tests. The test results are shown in Table 1.

[0074] Table 1 Test results

[0075]

[0076]

[0077] As can be seen from Table 1, in the 1C charge-discharge cycle test, the ZnZn@NF / Li||LFP battery has a higher capacity retention rate and cycle life than the bareNF / Li||LFP battery. In addition, by comparing the ZnZn@NF / Li electrodes with different treatment times, the ZnZn@NF / Li||LFP battery in Example 2 has a higher capacity retention rate and cycle life.

[0078] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0079] (1) The present embodiment adopts a one-step heat treatment method to prepare a three-dimensional carbon foam based on Zn modification, and uses it as a lithium metal negative electrode current collector for use in a negative electrode-free lithium metal soft pack battery;

[0080] (2) The preparation process of the zinc-containing current collector provided in the embodiment of the present application is simple. The zinc-containing current collector exhibits better electrochemical properties than the unmodified current collector, including lower deposition / dissolution overpotential and better cycle stability. The formed lithium metal soft-pack battery has a higher capacity retention rate and coulombic efficiency.

[0081] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for preparing a zinc-containing current collector, characterized in that: The method comprises: Under a set temperature, the zinc oxide powder, ammonia and the current collector matrix are heat treated so that the zinc oxide powder and the ammonia react chemically to generate zinc, and the zinc adheres to at least a portion of the surface of the current collector matrix to obtain a zinc-containing current collector.

2. The method according to claim 1, characterized in that The set temperature is 400°C to 900°C.

3. The method according to claim 1 or 2, characterized in that: The heat treatment time is 0.5h to 1.5h.

4. The method according to claim 1, characterized in that: The weight of the zinc oxide powder is 2mg-10mg, and the volume fraction of the ammonia gas is 5%-10%.

5. The method according to claim 1, characterized in that The temperature is raised to the set temperature at a set heating rate, wherein the set heating rate is 5°C / min to 10°C / min.

6. The method according to claim 1, characterized in that The current collector includes a three-dimensional carbon foam current collector.

7. A zinc-containing current collector, characterized in that: The zinc-containing current collector is prepared by the method according to any one of claims 1 to 6.

8. A negative electrode, characterized in that The negative electrode comprises the zinc-containing current collector according to claim 7.

9. The negative electrode according to claim 8, characterized in that The negative electrode is obtained by immersing the zinc-containing current collector in molten metal lithium.

10. A negative electrode-free lithium metal battery, characterized in that: The lithium metal battery comprises the negative electrode according to claim 8 or 9.

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