Three-dimensional porous dual-alloy current collector for metal lithium negative electrode, metal lithium negative electrode, and primary / secondary battery

Abstract

The application belongs to the technical field of batteries, and particularly relates to a three-dimensional porous double-alloy current collector for a metal lithium negative electrode, a metal lithium negative electrode and a primary / secondary battery. Zinc is electrochemically deposited on a pretreated foam copper surface to obtain a zinc-plated modified foam copper three-dimensional framework; the zinc-plated modified foam copper three-dimensional framework is placed in a tubular furnace for high-temperature calcination to form a three-dimensional porous Cu 0.64 Zn 0.36 and Cu5Zn8 double-alloy phase; and then a three-dimensional porous double-alloy current collector is formed by corrosion in an ammonia solution. The three-dimensional porous double-alloy phase can be corroded to make the three-dimensional porous double-alloy current collector have a large specific surface area, which is beneficial to reduce the local current density and reduce the formation of dendrites; the electrochemically active Cu5Zn8 has excellent lithium affinity, significantly reduces the lithium deposition overpotential, guides the uniform deposition of lithium, and further reduces dendrites. The electrochemically inert Cu 0.64 Zn 0.36 exhibits excellent structural stability and can effectively inhibit the volume change in the lithium deposition / stripping process.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a three-dimensional porous dual alloy current collector for lithium metal anodes, lithium metal anodes, and primary / secondary batteries. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] As electronic devices and electric vehicles place increasingly higher demands on battery capacity, existing commercially available and mature lithium-ion batteries can no longer meet these requirements. The main reason is that the theoretical specific capacity of the traditional graphite anode used in lithium-ion batteries is only 372 mAh. -1 The low energy density of lithium-ion batteries limits their capacity. To meet the capacity requirements of various devices, there is an urgent need for lithium anode materials with higher specific capacity. Lithium metal anodes possess extremely high capacity density (theoretical specific capacity of 3860 mA hg). -1 With its low relative potential (-3.040V vs. standard hydrogen electrode), lithium metal is the best candidate for future lithium-ion battery anode materials. However, the uneven distribution and transport of charge and charged particles, which leads to the growth of uneven dendrites on the surface, as well as problems such as unlimited volume changes and severe side reactions, hinder the application of lithium metal anodes.

[0004] Existing technologies disclose various methods for addressing lithium dendrite formation, including electrolyte modification, direct surface modification of the lithium metal anode, and the use of three-dimensional nanomaterials as current collectors to form a composite anode with lithium metal. However, electrolyte modification suffers from limited applicability and high cost; direct surface modification of the lithium metal anode also has limited applicability and high cost, and the preparation process is complex; the method of using three-dimensional nanomaterials as current collectors to form a composite anode with lithium metal suffers from poor lithium affinity, poor structural stability, and poor cycle stability. Summary of the Invention

[0005] To overcome the above problems, the present invention provides a three-dimensional porous dual alloy current collector for lithium metal anodes, a lithium metal anode, and a primary / secondary battery.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a three-dimensional porous dual-alloy current collector for a lithium metal anode, comprising the following steps:

[0008] (1) Zinc was electrochemically deposited on the pretreated foamed copper surface to obtain a zinc-modified three-dimensional framework of foamed copper.

[0009] (2) The zinc-modified copper foam three-dimensional skeleton obtained in step (1) is placed in a tube furnace and calcined at high temperature to form a three-dimensional porous Cu 0.64 Zn 0.36 and Cu5Zn8 bimetallic phase;

[0010] (3) The calcined copper-zinc alloy was placed in a 0.15-0.25 mol / L ammonia solution for 11-13 hours to form a three-dimensional porous dual alloy current collector.

[0011] In a second aspect, the present invention provides a three-dimensional porous dual alloy current collector prepared by the above-described preparation method.

[0012] A third aspect of the present invention provides a lithium metal anode comprising the above-described three-dimensional porous dual alloy current collector and lithium metal filling the pores of the three-dimensional porous dual alloy current collector.

[0013] A fourth aspect of the present invention provides a method for preparing the above-described lithium metal anode, comprising the following steps:

[0014] In the electrolyte, using the three-dimensional porous dual alloy current collector described in the second aspect as the positive electrode and lithium metal as the negative electrode, an electric current is passed through to obtain a lithium metal negative electrode.

[0015] A fifth aspect of the present invention provides a primary / secondary battery comprising the aforementioned lithium metal anode.

[0016] The beneficial effects of this invention are as follows:

[0017] (1) Three-dimensional porous Cu 064 Zn 036 After etching the Cu5Zn8 bialloy phase, the three-dimensional porous bialloy current collector has a large specific surface area, which is beneficial for reducing local current density and dendrite formation. Electrochemically active Cu5Zn8 has excellent lithiophilicity, significantly reducing lithium deposition overpotential, guiding uniform lithium deposition, and further reducing dendrite formation. Meanwhile, electrochemically inert Cu... 0.64 Zn 0.36 Exhibiting excellent structural stability, Cu effectively suppresses volume changes during lithium deposition / stripping. 0.64 Zn 0.36 The Cu5Zn8 dual alloy phase synergistically improves the cycle life and safety stability of lithium metal batteries.

[0018] (2) The results show that the electrochemical performance of the lithium metal anode prepared by the three-dimensional porous dual alloy current collector is significantly improved, and the symmetric cell achieves better performance at 1 mA cm⁻¹. -2Stable cycling for 900 hours at 5mA cm -2 It can be stably cycled for 300 hours at higher current densities. The lithium metal anode prepared by the three-dimensional porous dual alloy current collector exhibits excellent cycle stability and safety performance. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 These are scanning electron microscope images of the three-dimensional porous dual alloy current collector prepared in Example 1 at different magnifications;

[0021] Figure 2 The images show the XRD patterns of the copper-zinc alloy synthesized in Example 1 and the three-dimensional porous bialloy after etching, as well as the three-dimensional porous bialloys after etching in Comparative Examples 1 and 2.

[0022] Figure 3 XRD image of the lithium metal anode prepared in Example 2;

[0023] Figure 4 Various metallic lithium anodes prepared in Example 2 and pure lithium were subjected to 1 mA cm⁻¹. -2 and 5mA cm -2 Results of cyclic stability tests conducted at current density. Detailed Implementation

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] A first typical embodiment of the present invention provides a method for preparing a three-dimensional porous dual-alloy current collector for a lithium metal anode, comprising the following steps:

[0027] (1) Zinc was electrochemically deposited on the pretreated foamed copper surface to obtain a zinc-modified three-dimensional framework of foamed copper.

[0028] (2) The zinc-modified copper foam three-dimensional skeleton obtained in step (1) is placed in a tube furnace and calcined at high temperature to form a three-dimensional porous Cu 0.64 Zn 0.36 and Cu5Zn8 bimetallic phase;

[0029] (3) The calcined copper-zinc alloy was placed in a 0.15-0.25 mol / L ammonia solution for 11-13 hours to form a three-dimensional porous dual alloy current collector.

[0030] In one or more embodiments, the method for pretreating copper foam includes:

[0031] S1. Immerse the copper foam in hydrochloric acid solution and perform ultrasonic cleaning to remove oxides from the surface of the copper foam.

[0032] S2. Remove the foamed copper after cleaning with hydrochloric acid and rinse it with deionized water 3 to 5 times.

[0033] S3. After rinsing, ultrasonically clean the foamed copper with deionized water and dry it to obtain the pretreated foamed copper.

[0034] Preferably, the concentration of hydrochloric acid in step (1) is 0.5-1.5 mol / L, and the ultrasonic cleaning time is 13-18 min, preferably 15 min.

[0035] Preferably, the ultrasonic cleaning time of deionized water in step (3) is 13-18 minutes, preferably 15 minutes.

[0036] In one or more embodiments, the electroplating solution used for electrochemical zinc deposition is: 0.15-0.25M ZnSO4 + 0.15-0.25M Na2SO4 + 0.15-0.25M H3BO3, preferably 0.2M ZnSO4 + 0.2M Na2SO4 + 0.2M H3BO3.

[0037] In one or more embodiments, when electrochemically depositing zinc, the Amperometric it Curve electrochemical technique is used; the deposition voltage is -0.1 to -0.3V, preferably -0.2V.

[0038] In one or more embodiments, during the electrochemical deposition of zinc, pretreated copper foam is used as the working electrode, a saturated calomel electrode is used as the reference electrode, and a platinum sheet is used as the auxiliary electrode.

[0039] In one or more embodiments, the electrochemical deposition of zinc is carried out at room temperature; the deposition current is 40–60 mA / cm². 2 Preferably 50mA / cm 2 The deposition capacity is 9–11 mAh / cm³.2 Preferably 10mAh / cm 2 .

[0040] In one or more embodiments, when electrochemically depositing zinc, based on pretreated copper foam with a sheet shape of 2×2cm, a thickness of 0.8mm, and a mass of 0.12g, the deposition time is 700-750s, preferably 720s.

[0041] In one or more embodiments, in step (2), the high-temperature calcination temperature is 400-450°C, preferably 430°C; the high-temperature calcination time is 4.5-5.5h, preferably 5h.

[0042] A second typical embodiment of the present invention provides a three-dimensional porous dual alloy current collector prepared by the above preparation method.

[0043] A third typical embodiment of the present invention provides a lithium metal anode, comprising the above-mentioned three-dimensional porous dual alloy current collector and lithium metal filling the pores of the three-dimensional porous dual alloy current collector.

[0044] A fourth typical embodiment of the present invention provides a method for preparing the above-mentioned lithium metal anode, comprising the following steps:

[0045] In the electrolyte, using the three-dimensional porous dual alloy current collector described in the second aspect as the positive electrode and lithium metal as the negative electrode, an electric current is passed through to obtain a lithium metal negative electrode.

[0046] In one or more embodiments, the electrolyte comprises a solvent and a solute, wherein the solvent is a mixed solution of dioxane (DOL) and dimethyl ether (DME) in a volume ratio of 1:0.9 to 1.1, preferably 1:1; the solute is LiNO3, and the mass fraction of the solute is 1.5% to 2.5%, preferably 2%.

[0047] A fifth typical embodiment of the present invention provides a primary / secondary battery comprising the above-described lithium metal anode.

[0048] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0049] The manufacturer of the foamed copper is Suzhou Keshenghe Metal Materials.

[0050] Example 1

[0051] (1) Cut the 0.8 mm thick copper foam into 2×2 cm sheets, immerse them in 1 mol / L hydrochloric acid solution, and ultrasonically clean them for 15 min to remove the oxides on the surface of the copper foam; take out the copper foam after cleaning with hydrochloric acid and rinse it 4 times with deionized water; ultrasonically clean the rinsed copper foam with deionized water for 15 min and dry it in an oven at 60℃ to obtain the pretreated copper foam.

[0052] (2) The foamed copper was placed in a three-electrode system, with the pretreated foamed copper as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum sheet as the auxiliary electrode. The electroplating solution used was 0.2M ZnSO4 + 0.2M Na2SO4 + 0.2M H3BO3. Using the Amperometric it Curve electrochemical technique, the deposition voltage was -0.2V and the deposition current was 50mA / cm. 2 The deposition capacity is 10 mAh / cm³. 2 The deposition time was 720 s, thus obtaining a zinc-modified foamed copper three-dimensional framework.

[0053] (3) The zinc-modified foamed copper three-dimensional skeleton was placed in a tube furnace and calcined at 430°C for 5 hours to form a copper-zinc alloy.

[0054] (4) The calcined copper-zinc alloy was etched in a 0.2 mol / L ammonia solution for 12 h, and then dried in a 60℃ oven to form a three-dimensional porous Cu alloy. 0.64 Zn 0.36 And Cu5Zn8 dual alloy phase, namely a three-dimensional porous dual alloy current collector.

[0055] The scanning electron microscope image of the three-dimensional porous dual-alloy current collector prepared in this embodiment is as follows: Figure 1 As shown, from Figure 1 As can be seen, the three-dimensional framework structure of zinc-modified copper foam is observed at lower magnification, while the tightly packed nanosheet intercalation structure is observed at higher magnification.

[0056] Comparative Example 1

[0057] (1) Cut the 0.8 mm thick copper foam into 2×2 cm sheets, immerse them in 1 mol / L hydrochloric acid solution, and ultrasonically clean them for 15 min to remove the oxides on the surface of the copper foam; take out the copper foam after cleaning with hydrochloric acid and rinse it 4 times with deionized water; ultrasonically clean the rinsed copper foam with deionized water for 15 min and dry it in an oven at 60℃ to obtain the pretreated copper foam.

[0058] (2) The foamed copper was placed in a three-electrode system, with the pretreated foamed copper as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum sheet as the auxiliary electrode. The electroplating solution used was 0.2M ZnSO4 + 0.2M Na2SO4 + 0.2M H3BO3. Using the Amperometric it Curve electrochemical technique, the deposition voltage was -0.2V and the deposition current was 50mA / cm. 2 The deposition capacity is 10 mAh / cm³. 2 The deposition time was 720 s, thus obtaining a zinc-modified foamed copper three-dimensional framework.

[0059] (3) The zinc-modified foamed copper three-dimensional skeleton was placed in a tube furnace and calcined at 430°C for 5 hours to form a copper-zinc alloy.

[0060] (4) The calcined copper-zinc alloy was etched in a 0.2 mol / L ammonia solution for 24 hours, and then dried in a 60℃ oven to form a three-dimensional porous Cu alloy. 0.64 Zn 0.36 And Cu5Zn8 dual alloy phase, namely a three-dimensional porous dual alloy current collector.

[0061] Comparative Example 2

[0062] (1) Cut the 0.8 mm thick copper foam into 2×2 cm sheets, immerse them in 1 mol / L hydrochloric acid solution, and ultrasonically clean them for 15 min to remove the oxides on the surface of the copper foam; take out the copper foam after cleaning with hydrochloric acid and rinse it 4 times with deionized water; ultrasonically clean the rinsed copper foam with deionized water for 15 min and dry it in an oven at 60℃ to obtain the pretreated copper foam.

[0063] (2) The foamed copper was placed in a three-electrode system, with the pretreated foamed copper as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum sheet as the auxiliary electrode. The electroplating solution used was 0.2M ZnSO4 + 0.2M Na2SO4 + 0.2M H3BO3. Using the Amperometric it Curve electrochemical technique, the deposition voltage was -0.2V and the deposition current was 50mA / cm. 2 The deposition capacity is 10 mAh / cm³. 2 The deposition time was 720 s, thus obtaining a zinc-modified foamed copper three-dimensional framework.

[0064] (3) The zinc-modified foamed copper three-dimensional skeleton was placed in a tube furnace and calcined at 430°C for 5 hours to form a copper-zinc alloy.

[0065] (4) The calcined copper-zinc alloy was etched in a 0.2 mol / L ammonia solution for 48 hours, and then dried in a 60℃ oven to form a three-dimensional porous Cu alloy. 0.64Zn 0.36 And Cu5Zn8 dual alloy phase, namely a three-dimensional porous dual alloy current collector.

[0066] The properties of the copper-zinc alloy synthesized in Example 1, the three-dimensional porous bialloy after corrosion, and the three-dimensional porous bialloys after corrosion in Comparative Examples 1 and 2 were characterized, and their XRD images are shown below. Figure 2 As shown, from Figure 2 As can be seen from Example 1, the copper-zinc alloy synthesized contains Cu. 0.64 Zn 0.36 And the Cu5Zn8 bimetallic phase, after 12 hours of ammonia corrosion, also contains Cu. 0.64 Zn 0.36 And Cu5Zn8 bimetallic phase, but the copper-zinc alloys after 24h and 48h of ammonia corrosion only contain Cu 0.64 Zn 0.36 Alloy phase.

[0067] Example 2

[0068] A half-cell was prepared by placing lithium metal and the three-dimensional porous dual-alloy copper-zinc alloy current collector synthesized in Example 1 in a glove box filled with high-purity argon. Lithium metal deposition was performed using a blue electric cell testing system. The three-dimensional porous dual-alloy current collector served as the positive electrode, and lithium metal as the negative electrode. An electric current was passed through to obtain a lithium metal negative electrode. The electrolyte consisted of a solvent and a solute. The solvent was a mixed solution of DOL and DME in a 1:1 volume ratio, and the solute was LiNO3 with a mass fraction of 2%. The reaction was carried out at 1 mA cm⁻¹. -2 Lithium metal of different capacities was deposited at different current densities, with a deposition capacity of 20 mAh cm⁻¹. -2 .

[0069] The XRD image of the lithium metal anode prepared in this embodiment is as follows: Figure 3 As shown, a new phase LiZn alloy is formed after lithiation of a three-dimensional porous dual-alloy copper-zinc alloy current collector. The LiZn alloy exhibits high lithiophilicity and low Li nucleation barrier, and can maintain uniform lithium deposition even at high current densities.

[0070] The copper-zinc alloy synthesized in Example 1, and the three-dimensional porous bialloys etched in Comparative Examples 1 and 2 were respectively prepared into lithium metal anodes using the same preparation method in this example. Pure lithium and each lithium metal anode were then subjected to 1 mA cm⁻¹. -2 and 5mA cm -2 Cyclic stability tests were conducted at current density, and the results are as follows: Figure 4 As shown, the results indicate that the uncorroded copper-zinc alloy lithium metal anode exhibits high performance at 1 mA cm⁻¹. -2 It can be stably cycled for 270 hours at a current density, after which the polarization voltage surges. At 5 mA cm⁻¹ -2At a current density of [insert current density here], it only achieved stable cycling for 120 hours. The cycling performance of the uncorroded copper-zinc alloy lithium metal anode was far inferior to that of the three-dimensional porous dual-alloy lithium metal anode. The lithium metal anode prepared by the three-dimensional porous dual-alloy current collector showed significantly improved electrochemical performance, and the symmetric cell achieved stable cycling at 1 mA cm⁻¹. -2 Stable cycling for 900 hours at 5mA cm -2 It can be stably cycled for 300 hours at higher current densities. The lithium metal anode prepared by the three-dimensional porous dual alloy current collector exhibits excellent cycle stability and safety performance.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a three-dimensional porous dual-alloy current collector for lithium metal anodes, characterized in that, Includes the following steps: (1) Zinc was electrochemically deposited on the pretreated foamed copper surface to obtain a zinc-modified three-dimensional framework for foamed copper; (2) The zinc-modified foamed copper three-dimensional skeleton obtained in step (1) is placed in a tube furnace and calcined at high temperature to form a three-dimensional porous Cu 0.64 Zn 0.36 and Cu5Zn8 bimetallic phase; (3) The calcined copper-zinc alloy was placed in a 0.15~0.25 mol / L ammonia solution for 11~13 h to form a three-dimensional porous dual alloy current collector; In step (1), the electroplating solution used for electrochemical zinc deposition is: 0.15~0.25 M ZnSO4 + 0.15~0.25 M Na2SO4 + 0.15~0.25 M H3BO3; When electrochemically depositing zinc, the Amperometric it Curve electrochemical technique is used; the deposition voltage is -0.1 to -0.3V; pretreated copper foam is used as the working electrode, and a saturated calomel electrode is used as the reference electrode. A platinum sheet was used as the auxiliary electrode; the deposition temperature was room temperature; and the deposition current was 40–60 mA / cm². 2 The deposition capacity is 9~11 mAh / cm³. 2 The deposition time for pretreated copper foam, based on 2×2 cm sheets, 0.8 mm thick, and 0.12 g in weight, was 700–750 s. In step (2), the high-temperature calcination temperature is 400~450 ℃; the high-temperature calcination time is 4.5~5.5 h.

2. The three-dimensional porous dual-alloy current collector prepared by the preparation method of claim 1.

3. A lithium metal anode, comprising the three-dimensional porous dual alloy current collector as described in claim 2 and lithium metal filling the pores of the three-dimensional porous dual alloy current collector.

4. The method for preparing the lithium metal anode according to claim 3, characterized in that, Includes the following steps: In the electrolyte, using the three-dimensional porous dual alloy current collector as described in claim 2 as the positive electrode and lithium metal as the negative electrode, an electric current is passed through to obtain a lithium metal negative electrode.

5. The method for preparing a lithium metal anode as described in claim 4, characterized in that, The electrolyte comprises a solvent and a solute. The solvent is a mixed solution of dioxane and dimethyl ether, with a volume ratio of 1:0.9 to 1.

1. The solute is LiNO3, with a mass fraction of 1.5% to 2.5%.

6. A primary / secondary battery, characterized in that, Including the lithium metal anode as described in claim 3.

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