A preparation method and application of zinc-aluminum foil negative electrode immersed in zinc for lithium ion battery

Abstract

The application relates to a preparation method and application of a zinc-impregnated aluminum foil negative electrode applied to a lithium ion battery, and belongs to the field of lithium ion batteries. In view of the shortcomings and deficiencies of the aluminum foil as a lithium ion battery negative electrode material, a zinc-impregnated aluminum foil is prepared; the zinc-impregnated aluminum foil negative electrode prepared by the method has the advantages of smoothness, brightness, good corrosion resistance, high conductivity, low impedance, high charge-discharge rate, high first circle coulomb efficiency and small hysteresis phenomenon when the lithium foil is assembled into a half battery. Method: I. pretreatment of the aluminum foil; II. preparation of zinc-impregnated liquid; III. zinc-impregnated treatment. The zinc-impregnated aluminum foil negative electrode applied to the lithium ion battery is used as a negative electrode of the lithium ion battery. Compared with the half battery assembled by the traditional aluminum foil electrode, the zinc-impregnated aluminum foil electrode has higher charge-discharge rate and lower impedance, and also has higher first circle coulomb efficiency and more stable cycle performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of lithium ion batteries, and particularly relates to a preparation method of a zinc-aluminum foil negative electrode for a lithium ion battery and application thereof. BACKGROUND

[0002] Aluminum, as the most abundant metal element in the earth's crust, has outstanding advantages such as no pollution and low cost, and can deintercalate lithium at low potential (~0.2 V and ~0.4 V vs. Li 0 / Li + ) and has a larger theoretical specific capacity (993 mAh g -1 ) than graphite. Therefore, aluminum is an extremely attractive anode material for lithium ion batteries. Kuksenko proposed [Russ. J. Electrochemistry, 2013, Vol. 49, No. 1, pp. 67-75] to use aluminum foil as an "ideal anode material for lithium ion batteries". However, due to the existence of the surface oxide layer of the aluminum foil anode and the non-negligible volume change during alloying / dealloying, the aluminum foil anode has poor electrical conductivity and structural stability, which seriously limits the further application of aluminum-based anodes in lithium ion batteries. Therefore, it is necessary to further explore new research methods to further improve the electrochemical performance of aluminum-based anodes.

[0003] Due to the high reactivity of metallic aluminum, a layer of non-conductive aluminum oxide is easily formed on its surface, which causes the metallic aluminum foil anode to be in a passivated state. In addition, due to the poor electrical conductivity of aluminum oxide and the irreversible consumption of lithium during the formation of the SEI film, the capacity of the battery will rapidly decay, the initial coulombic efficiency will be poor, and other problems will occur. Therefore, the oxide layer on the surface of the aluminum foil not only hinders the transmission rate of lithium ions, but also reduces the initial coulombic efficiency [H. Wang, H. Tan, X. Luo, H. Wang, T. Ma, M. Lv, X. Song, S. Jin, X. Chang, X. Li, J. Mater. Chem. A 2020, 8, 25649]. The irreversible loss of lithium during alloying causes the unreacted surface layer of aluminum oxide to preferentially alloy along the rolling direction of the aluminum foil until the entire surface is alloyed with Li x AlO yCovering [D. Li, F. Chu, Z. He, Y. Cheng, F. Wu, Single-material aluminum foil as anodes enabling high-performance lithium-ion batteries: The roles of prelithiation and working mechanism, Materials Today, https: / / doi.org / 10.1016 / j.mattod.2022.07.004]. The research of Tahmasebi et al. [M. H. Tahmasebi, D. Kramer, R. S. T. Boles, J. Electrochem. Soc. 2019, 166, A5001], the lithiation of aluminum starts from the nucleation of the surface beta-LiAl phase, and these nucleation regions continue to expand until these regions are connected. Due to the presence of the aluminum oxide layer, the alloying reaction of the aluminum surface with lithium is extremely uneven. It can be seen that solving the problem of aluminum oxide plays an important role in realizing the practical application of aluminum-based negative electrode materials in lithium-ion batteries. However, there is currently no effective method to remove the aluminum oxide layer on the surface of aluminum, so the present application proposes a simple and effective method to remove the oxide layer on the surface of aluminum, that is, a dense zinc layer is formed in situ while removing the aluminum oxide layer to protect the aluminum from being oxidized again, thereby realizing high cycle performance in lithium-ion batteries. SUMMARY

[0004] The present application is directed to the shortcomings and deficiencies of the above-mentioned aluminum foil as a negative electrode material for lithium-ion batteries, and provides a preparation method and application of a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries.

[0005] The zinc-impregnated aluminum foil negative electrode prepared by the method of the present application is flat and bright, has good corrosion resistance, high electrical conductivity, and when assembled into a half-cell with a lithium foil, has the advantages of low impedance, high charge and discharge rate, high first-cycle coulombic efficiency, and small hysteresis phenomenon.

[0006] The present application is directed to the shortcomings and deficiencies of the above-mentioned aluminum foil as a negative electrode material for lithium-ion batteries, and provides a preparation method and application of a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries.

[0007] I. Pretreatment of aluminum foil:

[0008] The aluminum foil is immersed in a sodium hydroxide solution for a period of time, and after being taken out, it is washed with water to neutralize it, so as to remove the oxide layer on the surface of the aluminum foil, and obtain the pretreated aluminum foil;

[0009] II. Preparation of zinc-impregnated solution:

[0010] The sodium hydroxide, zinc oxide, additive and water are mixed uniformly to obtain the zinc-impregnated solution;

[0011] III. Zinc Immersion Treatment:

[0012] The pretreated aluminum foil is immersed in zinc immersion solution for a period of time, then removed, washed with water, and dried to obtain zinc-immersed aluminum foil negative electrode for lithium-ion batteries.

[0013] A zinc-plated aluminum foil negative electrode is used as the negative electrode in lithium-ion batteries.

[0014] Advantages of this invention:

[0015] The zinc-impregnated aluminum foil prepared using this invention exhibits stronger bonding between the zinc layer and the aluminum foil substrate, better corrosion resistance, and better wettability to the electrolyte compared to zinc-impregnated aluminum foil prepared without additives. When used in lithium-ion batteries with the zinc-impregnated aluminum foil anode and lithium foil prepared according to this invention, higher rate performance, lower impedance, and less hysteresis can be achieved. Furthermore, since the oxide layer on the aluminum foil surface is removed, lithium is not consumed due to reduction, and the zinc-impregnated aluminum foil has higher wettability to the electrolyte, significantly improving the rate capability of the aluminum foil electrode. Notably, without pre-lithiation, compared to half-cells assembled with conventional aluminum foil electrodes, the zinc-impregnated aluminum foil electrode exhibits higher charge / discharge rates and lower impedance, as well as higher first-cycle coulombic efficiency and more stable cycle performance.

[0016] In summary, the zinc-impregnated aluminum foil negative electrode prepared by this invention has excellent electrochemical performance. Attached Figure Description

[0017] Figure 1 The images show the morphology of the zinc-impregnated aluminum foil negative electrode prepared using the additive in Example 1 and the conventional aluminum foil negative electrode under an optical microscope.

[0018] Figure 2 The images show the morphology of the zinc-impregnated aluminum foil negative electrode prepared using additives in Example 2 and the zinc-impregnated aluminum foil negative electrode prepared without additives in Comparative Example 1, under a scanning electron microscope.

[0019] Figure 3 The half-cell assembled using the zinc-impregnated aluminum foil negative electrode prepared with additives in Example 1 was tested at 0.5 mA / cm. 2 and 2.0mAh / cm 2 Cyclic performance curve under capacity load;

[0020] Figure 4 Half-cells assembled using the zinc-plated aluminum foil negative electrode prepared with the additive of Example 2 and a conventional aluminum foil negative electrode were tested at 0.5 mA / cm. 2 and 2.0mAh / cm 2The figure shows the charge-discharge curves and cycle performance curves under capacity load; in the figure, a and d are half-cells assembled using conventional aluminum foil, b and e are half-cells assembled using zinc-impregnated aluminum foil without additives in Comparative Example 1, and c and f are half-cells assembled using zinc-impregnated aluminum foil prepared in Example 2. Detailed Implementation

[0021] Specific Implementation Method 1: This implementation method describes a method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries, specifically completed according to the following steps:

[0022] I. Pretreatment of Aluminum Foil:

[0023] The aluminum foil is immersed in a sodium hydroxide solution for a period of time, then washed with water until neutral to remove the oxide layer on the surface of the aluminum foil, thus obtaining the pretreated aluminum foil.

[0024] II. Preparation of zinc immersion solution:

[0025] Sodium hydroxide, zinc oxide, additives and water are mixed evenly to obtain zinc immersion solution;

[0026] III. Zinc Immersion Treatment:

[0027] The pretreated aluminum foil is immersed in zinc immersion solution for a period of time, then removed, washed with water, and dried to obtain zinc-immersed aluminum foil negative electrode for lithium-ion batteries.

[0028] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the soaking time in step one is 20s to 40s. The other steps are the same as in Specific Implementation Method One.

[0029] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the concentration of the sodium hydroxide solution mentioned in step one is 40 g / L to 50 g / L. The other steps are the same as in Specific Implementation Method One or Two.

[0030] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the temperature of the sodium hydroxide solution mentioned in step one is 80°C. The other steps are the same as in Specific Implementation Methods One to Three.

[0031] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the concentration of sodium hydroxide in the zinc immersion solution described in step two is 400 g / L to 500 g / L, the concentration of zinc oxide is 50 g / L to 100 g / L, and the concentration of the additive is 0.05 g / L to 5 g / L. The other steps are the same as in Specific Implementation Methods One to Four.

[0032] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the additive mentioned in step two is a mixture of two or more of the following: potassium sodium tartrate, erythrina gum, sodium sulfacetate, β-cyclodextrin, azoformamide, and 4-hexylresorcinol. The other steps are the same as in Specific Implementation Methods One to Five.

[0033] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the soaking time in step three is 2 seconds to 40 seconds. The other steps are the same as in Specific Implementation Methods One to Six.

[0034] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the temperature of the zinc immersion solution in step three is 25°C. The other steps are the same as in Specific Implementation Methods One to Seven.

[0035] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: the number of water washing cycles in step three is 2 to 4; the drying temperature in step three is 60°C, and the drying time is 1 hour. Other steps are the same as in Specific Implementation Methods One to Eight.

[0036] Specific Implementation Method 10: This implementation method is to use zinc-plated aluminum foil negative electrode as the negative electrode of lithium-ion battery.

[0037] The beneficial effects of the present invention are verified using the following embodiments:

[0038] Example 1: A method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries, specifically comprising the following steps:

[0039] I. Pretreatment of Aluminum Foil:

[0040] Using 99.95% pure aluminum foil as the substrate, a pretreatment process was performed. The specific method was as follows: the aluminum foil was immersed in a sodium hydroxide solution for 20 seconds, and then washed with water until neutral to remove the oxide layer on the surface of the aluminum foil, thus obtaining the pretreated aluminum foil.

[0041] The concentration of the sodium hydroxide solution mentioned in step one is 40 g / L;

[0042] The temperature of the sodium hydroxide solution mentioned in step one is 80℃;

[0043] II. Preparation of zinc immersion solution:

[0044] Sodium hydroxide, zinc oxide, erythrina gum, sodium sulfacetate and water are mixed evenly to obtain zinc immersion solution;

[0045] In step two, the concentration of sodium hydroxide in the zinc immersion solution is 500 g / L, the concentration of zinc oxide is 100 g / L, the concentration of erythrina gum is 3 g / L, and the concentration of sodium sulfacetate is 1.5 g / L.

[0046] III. Zinc Immersion Treatment:

[0047] The pretreated aluminum foil was immersed in zinc immersion solution for 2 seconds, then washed with water 3 times and dried to obtain zinc-immersed aluminum foil negative electrode for lithium-ion batteries (denoted as Al@Zn-2s).

[0048] The temperature of the zinc immersion solution mentioned in step three is 25°C;

[0049] The drying temperature in step three is 60°C, and the drying time is 1 hour.

[0050] Example 2: A method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries, specifically comprising the following steps:

[0051] I. Pretreatment of Aluminum Foil:

[0052] Using 99.95% pure aluminum foil as the substrate, a pretreatment process was performed. The specific method was as follows: the aluminum foil was immersed in a sodium hydroxide solution for 20 seconds, and then washed with water until neutral to remove the oxide layer on the surface of the aluminum foil, thus obtaining the pretreated aluminum foil.

[0053] The concentration of the sodium hydroxide solution mentioned in step one is 40 g / L;

[0054] The temperature of the sodium hydroxide solution mentioned in step one is 80℃;

[0055] II. Preparation of zinc immersion solution:

[0056] Sodium hydroxide, zinc oxide, potassium sodium tartrate, azodicarbonamide, β-cyclodextrin and water are mixed evenly to obtain a zinc immersion solution;

[0057] In step two, the concentration of sodium hydroxide in the zinc immersion solution is 500 g / L, the concentration of zinc oxide is 100 g / L, the concentration of potassium sodium tartrate is 2.5 g / L, the concentration of azodicarbonamide is 0.5 g / L, and the concentration of β-cyclodextrin is 0.8 g / L.

[0058] III. Zinc Immersion Treatment:

[0059] The pretreated aluminum foil was immersed in zinc immersion solution for 5 seconds, then washed with water 3 times and dried to obtain zinc-immersed aluminum foil negative electrode for lithium-ion batteries (denoted as Al@Zn-5s).

[0060] The temperature of the zinc immersion solution mentioned in step three is 25°C;

[0061] The drying temperature in step three is 60°C, and the drying time is 1 hour.

[0062] Comparative Example 1: The difference between this example and Example 2 is that in step two, sodium hydroxide, zinc oxide and water are mixed evenly to obtain a zinc immersion solution;

[0063] In step two, the concentration of sodium hydroxide in the zinc immersion solution is 500 g / L, and the concentration of zinc oxide is 100 g / L. All other steps and parameters are the same as in Example 2.

[0064] Figure 1 The images show the morphology of the zinc-impregnated aluminum foil negative electrode prepared using the additive in Example 1 and the conventional aluminum foil negative electrode under an optical microscope.

[0065] from Figure 1 It is known that the surface of traditional aluminum foil anodes has many uneven vertical stripes, which increases the surface roughness of the traditional aluminum foil. This leads to uneven alloying of lithium ions on the surface of the traditional aluminum foil, resulting in uneven stress distribution and structural damage. In contrast, the aluminum foil surface of Example 1, after being immersed in zinc with additives, is covered with a dense and uniform zinc layer. During charging and discharging, the dense zinc layer promotes uniform alloying of lithium ions on its surface, alleviating structural failure caused by stress and thus extending cycle life.

[0066] Figure 2 The images show the morphology of the zinc-impregnated aluminum foil negative electrode prepared using additives in Example 2 and the zinc-impregnated aluminum foil negative electrode prepared without additives in Comparative Example 1, under a scanning electron microscope.

[0067] from Figure 2 It can be seen that the zinc layer of the zinc-immersed aluminum foil negative electrode prepared using additives in Example 2 is dense, uniform, and has a wide coverage area; while the zinc layer of the zinc-immersed aluminum foil negative electrode prepared without additives in Comparative Example 1 is rough and has a small coverage area.

[0068] The zinc-impregnated aluminum foil prepared in Examples 1 and 2, the zinc-impregnated aluminum foil without additives in Comparative Example 1, and the conventional aluminum foil were made into electrode sheets with the same surface area in a stamping machine and used as negative electrode materials for lithium-ion batteries.

[0069] Following the button cell assembly structure, zinc-impregnated aluminum foil prepared in Examples 1 and 2 after lamination, zinc-impregnated aluminum foil without additives in Comparative Example 1, and conventional aluminum foil were assembled with lithium foil to form half-cells; under constant current mode, 0.5 mA / cm² was used. 2 The current density is such that it can be charged to 2.0 mAh / cm³. 2 The capacity load is limited, and the discharge termination voltage is limited to 0.9V. The cycling results are as follows: Figure 3 , Figure 4 As shown;

[0070] Figure 3 The half-cell assembled using the zinc-impregnated aluminum foil negative electrode prepared with additives in Example 1 was tested at 0.5 mA / cm. 2 and 2.0mAh / cm 2 Cyclic performance curve under capacity load;

[0071] from Figure 3 As can be seen, the zinc-impregnated aluminum foil anode prepared using the additives in Example 1 can be stably cycled up to 450 cycles while maintaining a high average coulombic efficiency of 96.85%.

[0072] Figure 4 Half-cells assembled using the zinc-plated aluminum foil negative electrode prepared with the additive of Example 2 and a conventional aluminum foil negative electrode were tested at 0.5 mA / cm. 2 and 2.0mAh / cm 2 The charge-discharge curves and cycle performance curves under capacity load are shown in the figure; a and d are half-cells assembled using conventional aluminum foil, b and e are half-cells assembled using zinc-impregnated aluminum foil without additives in Comparative Example 1, and c and f are half-cells assembled using zinc-impregnated aluminum foil prepared in Example 2.

[0073] from Figure 4 As can be seen, the half-cell with the zinc-impregnated aluminum foil negative electrode prepared using the additive in Example 2 has a charge-discharge voltage difference that is 50 mV smaller than that of the half-cell with the conventional aluminum foil and the zinc-impregnated aluminum foil negative electrode without the additive at the 10th cycle. This indicates that the zinc-impregnated aluminum foil negative electrode has lower impedance. Furthermore, the cycle life of the zinc-impregnated aluminum foil negative electrode prepared using this invention is approximately 300 cycles, while the conventional aluminum foil negative electrode can only cycle for about 170 cycles, and the zinc-impregnated aluminum foil without the additive can only cycle for about 275 cycles. This demonstrates that the dense and compact zinc layer prepared by this invention can effectively protect the aluminum foil negative electrode from failure during cycling, resulting in more stable electrochemical performance and a longer cycle life.

Claims

1. A method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries, characterized in that... The preparation method is specifically carried out according to the following steps: I. Pretreatment of Aluminum Foil: The aluminum foil is immersed in a sodium hydroxide solution for a period of time, then washed with water until neutral to remove the oxide layer on the surface of the aluminum foil, thus obtaining the pretreated aluminum foil. II. Preparation of zinc immersion solution: Sodium hydroxide, zinc oxide, additives and water are mixed evenly to obtain zinc immersion solution; In step two, the concentration of sodium hydroxide in the zinc immersion solution is 400 g / L to 500 g / L, the concentration of zinc oxide is 50 g / L to 100 g / L, and the concentration of additives is 0.05 g / L to 5 g / L. The additives mentioned in step two are two or more of the following: potassium sodium tartrate, aralia elata gum, sodium sulfacetate, β-cyclodextrin, azodicarbonamide and 4-hexylresorcinol; III. Zinc Immersion Treatment: The pretreated aluminum foil is immersed in zinc immersion solution for a period of time, then taken out, washed with water, and dried to obtain zinc-immersed aluminum foil negative electrode for lithium-ion batteries. The soaking time described in step three is 2 to 40 seconds.

2. The method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries according to claim 1, characterized in that... The soaking time described in step one is 20s to 40s.

3. The method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries according to claim 1, characterized in that... The concentration of the sodium hydroxide solution mentioned in step one is 40 g / L to 50 g / L.

4. The method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries according to claim 1, characterized in that... The temperature of the sodium hydroxide solution mentioned in step one is 80°C.

5. The method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries according to claim 1, characterized in that... The temperature of the zinc immersion solution mentioned in step three is 25°C.

6. The method for preparing a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries according to claim 1, characterized in that... The number of water washing cycles in step three is 2 to 4; the drying temperature in step three is 60℃, and the drying time is 1 hour.

7. The application of a zinc-impregnated aluminum foil negative electrode for lithium-ion batteries prepared by the method described in claim 1, characterized in that... A zinc-plated aluminum foil negative electrode is used as the negative electrode in lithium-ion batteries.

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