Method for depositing ZnTi alloy on surface of negative electrode of lithium metal battery

Abstract

The invention relates to the field of battery materials, in particular to a method for depositing ZnTi alloy on the surface of a lithium metal battery negative electrode. The method comprises the steps that 1, a substrate suitable for the lithium metal negative electrode is selected, cleaned and dried; (2) weighing Zn oxide powder and Ti oxide powder in proportion, uniformly mixing, and melting in vacuum to obtain a mixed melt; (3) quickly putting a substrate into the mixed melt by using a manipulator, repeatedly dip-coating, forming a plurality of layers of films on the surface of the substrate, taking out, and naturally cooling; and 4) reducing the Zn and Ti oxides on the dip-coated substrate into an alloy of Zn and Ti, carrying out acid pickling, cleaning and heat treatment, and cooling to normal temperature. According to the invention, a layer of uniform and compact film is formed on the surface of the lithium metal negative electrode after reduction by dip-coating the mixed melt of the molten Zn oxide and Ti oxide, so that the growth of lithium dendrites is effectively inhibited, the cycle life of the battery is prolonged, and the safety performance of the battery is improved; the ZnTi alloy can also improve the coulombic efficiency and the charge-discharge performance of the lithium metal negative electrode.

Description

Technical Field

[0001] This invention relates to the field of battery materials, and more particularly to a method for depositing ZnTi alloy on the surface of a lithium metal battery anode. Background Technology

[0002] Lithium metal batteries have attracted much attention due to their high energy density and long cycle life. However, lithium metal anodes are prone to lithium dendrite formation during charge and discharge, leading to performance degradation and even safety accidents. Furthermore, the unstable SEI film on the surface of the lithium metal anode also affects the battery's coulombic efficiency and cycle life. Therefore, effectively improving the performance of lithium metal anodes has become a key issue restricting the commercial application of lithium metal batteries. Summary of the Invention

[0003] To address the problem of instability on the surface of lithium metal anodes in existing lithium metal batteries affecting battery performance, this invention provides a method for depositing ZnTi alloy on the surface of lithium metal battery anodes, comprising the following steps: 1) Substrate processing Select a suitable substrate for lithium metal anodes, clean and dry it, and set it aside; 2) Preparation of mixed powder containing Zn and Ti Weigh out Zn oxide powder and Ti oxide powder in proportion, mix them evenly, and then melt them under vacuum to obtain a mixed melt; 3) Substrate dip coating The substrate from step 1) is quickly immersed in the mixed melt from step 2) using a robotic arm for repeated dipping and coating to form a multi-layer thin film on the substrate surface. After removal, it is allowed to cool naturally. 4) Reduction process The Zn oxide and Ti oxide on the substrate after dip coating in step 3) are reduced to an alloy of Zn and Ti. Then, the substrate is placed in hydrochloric acid for acid washing. After cleaning, it is heat-treated and cooled to room temperature to obtain the lithium metal battery negative electrode with ZnTi alloy deposited on the surface.

[0004] Specifically, the substrate of this invention is copper foil or nickel foil, the Zn oxide is ZnO, and the Ti oxide is TiO2; the molar ratio of Zn to Ti is 1:(0.5~1.5).

[0005] Specifically, the reduction method used in this invention is either hydrogen reduction or metal displacement.

[0006] The intended effects of this invention are as follows: by dipping in a molten mixture of Zn oxide and Ti oxide, a uniform and dense ZnTi alloy film can be formed on the surface of the lithium metal anode after reduction, which effectively inhibits the growth of lithium dendrites and improves the cycle life and safety performance of the battery; the ZnTi alloy has good electrochemical performance and can improve the coulombic efficiency and charge-discharge performance of the lithium metal anode. Detailed Implementation

[0007] The present invention will be described below with reference to examples. These examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0008] Example 1 A method for depositing ZnTi alloy on the surface of a lithium metal battery anode includes the following steps: selecting nickel foil as a substrate, and pre-treating it by cleaning and drying; weighing ZnO and TiO2 powders according to a Zn to Ti molar ratio of 1:1, mixing them evenly, and then melting them using a vacuum melting method, controlling the vacuum furnace pressure at 1 Pa and the temperature at 2100℃ to obtain a mixed melt; quickly placing the substrate into the mixed melt using a robotic arm, holding it for 3 seconds, then removing it, suspending it vertically until no melt drips down, and then placing it back in; repeating this dipping process 4 times; removing it and allowing it to cool naturally to form 4 layers of mixed oxide film on the substrate surface; slowly reducing it in a hydrogen gas flow at 200℃ for 12 hours to form a ZnTi alloy film; heat-treating the nickel foil at 200℃ for 1 hour, and then allowing it to cool naturally to obtain the final product.

[0009] Example 2 A method for depositing ZnTi alloy on the surface of a lithium metal battery anode includes the following steps: selecting copper foil as a substrate, and pre-treating it by cleaning and drying; weighing ZnO and TiO2 powders according to a Zn to Ti molar ratio of 1:1.5, mixing them evenly, and then melting them using a vacuum melting method, controlling the vacuum furnace pressure at 1 Pa and the temperature at 2100℃ to obtain a mixed melt; quickly placing the substrate into the mixed melt using a robotic arm, holding it for 5 seconds, then removing it, suspending it vertically until no melt drips down, and then placing it back in; repeating this dipping process twice; removing it and allowing it to cool naturally to form two mixed oxide films on the substrate surface; under argon protection, slowly reducing the substrate in a Na metal melt at 500℃ for 24 hours to form a ZnTi alloy film; removing it, cleaning it with dilute hydrochloric acid and water, heat-treating it at 200℃ for 1 hour, and then allowing it to cool naturally to obtain the final product.

[0010] Example 3 A method for depositing ZnTi alloy on the surface of a lithium metal battery anode includes the following steps: selecting copper foil as a substrate, and pre-treating it by cleaning and drying; weighing ZnO and TiO2 powders according to a Zn to Ti molar ratio of 1:0.5, mixing them evenly, and then melting them using a vacuum melting method, controlling the vacuum furnace pressure at 1 Pa and the temperature at 2100℃ to obtain a mixed melt; quickly placing the substrate into the mixed melt using a robotic arm, holding it for 2 seconds, then removing it, suspending it vertically until no melt drips down, and then placing it back in; repeating this dipping process 3 times; removing it and allowing it to cool naturally to form a 3-layer mixed oxide film on the substrate surface; slowly reducing it in a hydrogen gas flow at 200℃ for 12 hours to form a ZnTi alloy film; heat-treating the nickel foil at 200℃ for 1 hour, and then allowing it to cool naturally to obtain the final product.

[0011] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for depositing ZnTi alloy on the surface of a lithium metal battery anode, characterized in that, Includes the following steps: 1) Substrate processing Select a suitable substrate for lithium metal anodes, clean and dry it, and set it aside; 2) Preparation of mixed powder containing Zn and Ti Weigh out Zn oxide powder and Ti oxide powder in proportion, mix them evenly, and then melt them under vacuum to obtain a mixed melt; 3) Substrate dip coating The substrate from step 1) is quickly immersed in the mixed melt from step 2) using a robotic arm for repeated dipping and coating to form a multi-layer thin film on the substrate surface. After removal, it is allowed to cool naturally. 4) Reduction process The Zn oxide and Ti oxide on the substrate after dip coating in step 3) are reduced to an alloy of Zn and Ti. Then, the substrate is placed in hydrochloric acid for acid washing. After cleaning, it is heat-treated and cooled to room temperature to obtain the lithium metal battery negative electrode with ZnTi alloy deposited on the surface.

2. The method of depositing ZnTi alloy on the surface of a lithium metal battery negative electrode according to claim 1, wherein, The substrate is a copper foil or a nickel foil.

3. The method for depositing ZnTi alloy on the surface of a lithium metal battery anode according to claim 1, characterized in that, The Zn oxide is ZnO, and the Ti oxide is TiO2.

4. The method for depositing ZnTi alloy on the surface of a lithium metal battery anode according to claim 1, characterized in that, The molar ratio of Zn to Ti is 1:(0.5~1.5).

5. The method for depositing ZnTi alloy on the surface of a lithium metal battery anode according to claim 1, characterized in that, The reduction method is either hydrogen reduction or metal displacement.