A gallium-based alloy, a preparation method and application thereof

Abstract

This invention discloses a gallium-based alloy, its preparation method, and its application. The preparation method includes: mixing and grinding metallic gallium with one or more metals selected from other metals besides metallic gallium to form an alloy, and then annealing it at a temperature of 30-400℃. When the gallium-based alloy prepared by this method is used to make a negative electrode and further applied to a battery, it can suppress the continuous growth of dendrites in the negative electrode of the battery, make ions deposit uniformly, increase the electrode-electrolyte contact area, improve the critical current density, and accelerate the heat dissipation of the battery, thereby improving safety and improving the cycle performance of the battery. It effectively solves the problem of short cycle life of metal secondary batteries. Moreover, the method is simple and effective, the process is simple, efficient, and the conditions are mild.

Description

Technical Field

[0001] This invention relates to the field of electrochemical devices, specifically to a gallium-based alloy, its preparation method, and its applications. Background Technology

[0002] With the increasing scarcity of traditional resources and energy, and the growing severity of environmental problems, the development of new energy storage and conversion technologies has become a key focus of national energy strategies. Energy storage devices, represented by lithium metal batteries and sodium metal batteries, play a crucial role in energy storage and conversion. Lithium and sodium metals are considered preferred materials for significantly improving battery energy density due to their high specific capacity and low electrode potential. However, during battery cycling, lithium and sodium metal anodes continuously form dendrites, which continuously consume electrolyte, leading to low coulombic efficiency and reduced cycle life. More seriously, the continuous growth of dendrites can puncture the separator, causing internal short circuits, and the accumulated heat can easily lead to battery safety accidents. Summary of the Invention

[0003] The purpose of this invention is to overcome one or more deficiencies in the prior art and provide an improved method for preparing gallium-based alloys. When the gallium-based alloys prepared by this method are used to make negative electrodes and applied to batteries, they can suppress the continuous growth of negative electrode dendrites in the battery, accelerate the heat dissipation of the battery, and improve the cycle performance of the battery while providing a high-safety negative electrode with uniform ion deposition.

[0004] The present invention also provides a gallium-based alloy prepared by the above method.

[0005] The present invention also provides a gallium-based alloy anode material comprising the gallium-based alloy prepared by the above method and its application as an anode in the preparation of batteries.

[0006] To achieve the above objectives, the present invention provides a technical solution: a method for preparing a gallium-based alloy, the method comprising: mixing and grinding metallic gallium with one or more metals selected from other metals besides the metallic gallium, forming an alloy, and then annealing it at a temperature of 30-400°C.

[0007] According to some preferred aspects of the invention, the annealing process is performed at a temperature of 50-350°C. Further, the annealing process is performed at a temperature of 80-200°C.

[0008] In some embodiments of the present invention, the annealing treatment is performed at temperatures of 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, or 200°C.

[0009] In some preferred and specific embodiments of the present invention, the annealing time of the annealing process is controlled to be 0.5-2h, for example, it can be 0.5h, 0.6h, 0.8h, 1h, 1.5h, 1.8h, etc.

[0010] According to some preferred aspects of the invention, the mixing and grinding and the annealing treatment are carried out under a protective atmosphere, which is formed by introducing nitrogen and / or an inert gas.

[0011] According to some preferred aspects of the present invention, the other metals include, but are not limited to, one, two or more combinations selected from lithium, sodium, potassium, calcium, magnesium, indium, iron, copper, manganese, gold, silver, zinc, platinum, cobalt, tin, nickel, antimony, ruthenium, aluminum, titanium, and tungsten.

[0012] In this invention, after lithium ions gain electrons at the negative electrode and are reduced to lithium atoms, they need a certain diffusion path to combine with the alloy negative electrode to form an alloy or solid solution. Therefore, limiting the molar ratio of gallium to other metals is more conducive to forming a path for lithium diffusion, thereby helping to suppress the formation of dendrites on the negative electrode surface. According to some preferred aspects of the invention, the molar ratio of gallium to other metals is 0.1-10:1, for example, it can be 0.1:1, 2:1, 3:1, 5:1, 7:1, 8:1, 9:1, 10:1, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0013] More preferably, in some embodiments of the present invention, the molar ratio of gallium to the other metals is 0.5-10:1. In some other embodiments, the molar ratio of gallium to the other metals can be 1-10:1.

[0014] In some preferred embodiments of the present invention, the preparation of the gallium-based alloy includes:

[0015] Under a protective atmosphere, metallic gallium is mixed and ground with one or more metals selected from other metals besides said metallic gallium until they are completely fused to form an alloy;

[0016] The alloy obtained by grinding is then annealed under a protective atmosphere at a temperature of 30-400℃ and held at that temperature.

[0017] Another technical solution provided by the present invention: a gallium-based alloy prepared by the above-described method for preparing gallium-based alloys.

[0018] Another technical solution provided by the present invention is a gallium-based alloy anode material, which comprises the gallium-based alloy described above.

[0019] In this invention, the gallium-based alloy anode material may consist solely of a gallium-based alloy, or it may further include an inactive substance that does not participate in the lithium deposition reaction and forms a complex with the gallium-based alloy. In some embodiments, the inactive substance includes one or more combinations selected from oxides (e.g., magnesium oxide, calcium oxide, zirconium oxide, etc.), carbon, and chlorides (e.g., magnesium chloride, calcium chloride, sodium chloride, etc.).

[0020] In some embodiments of the present invention, the gallium-based alloy anode material further includes an ionic conductive agent (e.g., a halide electrolyte, a sulfide electrolyte, an oxide electrolyte, etc.). For example, when used in solid-state batteries, the gallium-based alloy described above can be mixed with the ionic conductive agent to form an electrode material. The type and content of the ionic conductive agent can be adjusted and selected according to different battery systems.

[0021] Another technical solution provided by the present invention: the application of the above-mentioned gallium-based alloy anode material as an anode in the preparation of batteries.

[0022] In some embodiments of the present invention, the battery includes various types of batteries such as solid-state batteries, liquid batteries, or flow batteries;

[0023] Solid-state batteries are batteries that use solid electrodes and solid electrolytes. Solid-state batteries generally have lower power density but higher energy density. Solid-state batteries include, but are not limited to, lithium batteries, sodium batteries, magnesium batteries, calcium batteries, potassium batteries, etc.

[0024] A liquid battery is a battery consisting of a glass container in which electrochemically active electrodes are immersed in an electrolyte.

[0025] A flow battery consists of a stack unit, electrolyte, electrolyte storage and supply unit, and management and control unit. Flow batteries are high-performance batteries that utilize separate, independently circulating electrolytes at the positive and negative electrodes. They are characterized by high capacity, wide applicability (in various environments), and long cycle life. Flow batteries achieve the interconversion of electrical and chemical energy through reversible redox reactions (i.e., reversible changes in valence states) between the active materials in the electrolyte solutions at the positive and negative electrodes. During charging, oxidation occurs at the positive electrode, increasing the valence state of the active materials, while reduction occurs at the negative electrode, decreasing the valence state. The discharge process is the reverse.

[0026] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0027] Through extensive experimental research, the inventors of this invention discovered that by first mixing the various metals through grinding to form an alloy, and then annealing it at a relatively low and specific temperature range, a pure-phase gallium-based alloy can be obtained. This alloy effectively suppresses dendrite growth in the negative electrode, exhibiting an unexpectedly strong suppression effect, achieving uniform ion deposition, reducing battery safety hazards, improving battery safety, and enhancing battery cycle performance. Practical application has shown that when the gallium-based alloy prepared by this invention is applied to the negative electrode of lithium batteries, it can enable the critical current density of batteries, such as all-solid-state batteries, to reach 10 mA / cm². 2 The above can be stably cycled more than 500 times;

[0028] Furthermore, through research and analysis by the inventors, it is believed that the gallium-based alloy prepared by the method of this invention has a relatively low chemical potential and can enable alkali metal ions to form alloys or solid solutions when deposited on the negative electrode, thereby effectively suppressing the growth of dendrites on the negative electrode, increasing the electrode-electrolyte contact area, and improving the critical current density of the battery. Thus, while providing high safety and uniform ion deposition, it also improves the cycle life of the battery.

[0029] Furthermore, this invention not only effectively solves the problem of short cycle life of metal secondary batteries, but also has a simple and effective method, convenient process, high efficiency, and mild conditions. Attached Figure Description

[0030] Figure 1 The X-ray diffraction pattern of the lithium-gallium alloy prepared in Example 1 of this invention;

[0031] Figure 2 The first charge-discharge curve of the all-solid-state battery (commercial high-nickel ternary NCM811 as the positive electrode) prepared in Example 1 of the present invention;

[0032] Figure 3 The image shows the cycle performance test results of the all-solid-state battery (using commercially available high-nickel ternary NCM811 as the cathode) prepared in Example 1 of this invention.

[0033] Figure 4 This is a constant current charge-discharge test diagram of the all-solid-state symmetric battery prepared in Example 1 of the present invention;

[0034] Figure 5 The charge-discharge curves of the all-solid-state battery (with lithium metal as the counter electrode) prepared in Example 2 of the present invention are shown.

[0035] Figure 6 The X-ray diffraction pattern of the lithium gallium alloy prepared in Comparative Example 1 of this invention is shown below.

[0036] Figure 7 The first charge-discharge curve of the all-solid-state battery (commercial high-nickel ternary NCM811 as the positive electrode) prepared in Comparative Example 1 of the present invention;

[0037] Figure 8 The first charge-discharge curve of the all-solid-state battery (commercial high-nickel ternary NCM811 as the positive electrode) prepared in Comparative Example 2 of the present invention;

[0038] Figure 9 The X-ray diffraction pattern of the lithium gallium alloy prepared in Comparative Example 3 of this invention is shown below.

[0039] Figure 10 The first charge-discharge curve of the all-solid-state battery (commercial high-nickel ternary NCM811 as the positive electrode) prepared in Comparative Example 4 of the present invention is shown. Detailed Implementation

[0040] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0041] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0042] Example 1

[0043] This embodiment provides a lithium gallium alloy, its preparation method, and a further prepared lithium gallium alloy anode material.

[0044] The preparation method of this lithium-gallium alloy includes:

[0045] 0.7g of gallium metal and 0.1g of lithium metal were weighed separately and manually ground in an agate mortar and pestle inside a glove box until they were completely fused together to form an alloy. The ground material was then annealed under an argon atmosphere at 180℃ for 2 hours to form a Li3Ga2 alloy. The X-ray diffraction pattern of this alloy is shown in [reference needed]. Figure 1 .

[0046] The Li3Ga2 alloy obtained after the above heat preservation was allowed to stand, cooled and pressed. The standing time was 1 hour to obtain the lithium gallium alloy anode material.

[0047] The lithium-gallium alloy anode material obtained in this example was used to assemble an all-solid-state battery, and constant current charge-discharge tests were conducted. The lithium-gallium alloy anode material obtained in this example was used as the anode, Li6PS5Cl as the electrolyte, and a commercially available high-nickel ternary cathode was used as the cathode. The charge-discharge current density was 0.5 mA / cm². 2 The initial charge-discharge curve of this all-solid-state battery can be found in [reference needed]. Figure 2 As shown, by Figure 2 It can be seen that the average voltage of this all-solid-state battery is around 3.8V, which is within the normal operating voltage range of this high-nickel ternary cathode, and the battery exhibits good cycle performance. Figure 3 As shown, after 500 cycles, the capacity retention rate remains high with almost no decrease, and the retention rate is above 98%.

[0048] The lithium-gallium alloy anode material obtained in this example was used to assemble an all-solid-state symmetric battery, and constant current charge-discharge tests were performed. Figure 4 It can be seen that the battery operates at 25mA / cm 2 It can still cycle stably at current densities, exhibiting an extremely high critical current density of at least 10 mA / cm². 2 above.

[0049] Example 2

[0050] This embodiment provides a sodium gallium alloy, its preparation method, and a further prepared sodium gallium alloy anode material.

[0051] The preparation method of this sodium-gallium alloy includes:

[0052] 0.7g of gallium metal and 0.33g of sodium metal were weighed separately and manually ground in a glove box using an agate mortar until they were completely fused together to form an alloy. The ground material was then annealed under an argon atmosphere at a temperature of 120℃ for 2 hours to form a Na3Ga2 alloy.

[0053] The Na3Ga2 alloy obtained after the above heat preservation was allowed to stand, cooled and pressed. The standing time was 1 hour to obtain the sodium gallium alloy anode material.

[0054] The sodium-gallium alloy anode material obtained in this example was used to assemble an all-solid-state battery, and constant current charge-discharge tests were conducted. Metallic sodium was used as the counter electrode, Na3PS4 as the electrolyte, and the sodium-gallium alloy anode material obtained in this example was used as the working electrode. The charge-discharge current was 3 mA / cm². 2 The charge / discharge time was set to 1 hour. The charge / discharge curve for this all-solid-state battery can be found in [reference needed]. Figure 5 As shown in the figure, the sodium intercalation potential of this battery is less than 0.3V, indicating that this negative electrode can exhibit a low potential when applied to a sodium battery.

[0055] Compare with Example 1

[0056] This comparative example provides a lithium gallium alloy, its preparation method, and a further prepared lithium gallium alloy anode material.

[0057] The preparation method of this lithium-gallium alloy includes:

[0058] 0.7 g of gallium metal and 0.1 g of lithium metal were mixed and directly heated under an argon atmosphere at 800 °C for 2 hours to form Li. x Ga y alloy. Figure 6 Li prepared for this comparative example 1 x Ga y The X-ray diffraction pattern of the alloy shows that the lithium-gallium alloy prepared by this method has obvious impurity phases.

[0059] The Li obtained after the above heat preservation x Ga y After the alloy block is left to stand, cooled, ground into powder and pressed, the standing time is 1 hour to obtain lithium gallium alloy anode material.

[0060] The lithium gallium alloy anode material obtained in Comparative Example 1 was used to assemble an all-solid-state battery, and charge-discharge tests were conducted. The lithium gallium alloy anode material in Comparative Example 1 was used as the anode, Li6PS5Cl as the electrolyte, and a commercially available high-nickel ternary cathode was used as the cathode. The current density was 0.5 mA / cm². 2 The initial charge-discharge curve of this all-solid-state battery can be found in [reference needed]. Figure 7 As shown, the potential of its negative electrode is found to be high, and the overall voltage platform of the battery is low. It is believed that this is due to the presence of more impurities in the lithium gallium alloy.

[0061] Compare with Example 2

[0062] Same as in Example 1, but without grinding.

[0063] The lithium gallium alloy anode material obtained in Comparative Example 2 was used to assemble an all-solid-state battery, and constant current charge-discharge tests were performed. The lithium gallium alloy anode material obtained in Comparative Example 2 was used as the anode, Li6PS5Cl as the electrolyte, and a commercially available high-nickel ternary electrode as the cathode. The charge-discharge current density was 0.5 mA / cm². 2 The initial charge-discharge curve of this all-solid-state battery can be found in [reference needed]. Figure 8 As shown, by Figure 8 It can be observed that the potential of the negative electrode is also too high, and the overall voltage platform of the battery is too low. It is believed that this is due to the insufficient purity of the lithium gallium alloy obtained by the method in Comparative Example 2, which should contain a lot of impurities, thus affecting the electrical performance.

[0064] Compare with Example 3

[0065] It is basically the same as Example 1, except that the annealing temperature is 420°C.

[0066] The X-ray diffraction pattern of the lithium-gallium alloy obtained in Comparative Example 3 is shown in [reference needed]. Figure 9 As shown, by Figure 9 It can be seen that the presence of a pure lithium metal phase indicates that the lithium-gallium alloy prepared by the method in this control also has obvious impurity phases, and the purity of the obtained lithium-gallium alloy is obviously not high.

[0067] Compare with Example 4

[0068] The process is basically the same as in Example 1, except that the order of grinding and annealing is adjusted. Specifically, the process is to first heat and melt at 180°C and then grind.

[0069] The lithium gallium alloy anode material obtained in this comparative example was used to assemble an all-solid-state battery, and constant current charge-discharge tests were conducted. The lithium gallium alloy anode material obtained in this comparative example was used as the anode, Li6PS5Cl as the electrolyte, and a commercially available high-nickel ternary cathode was used as the cathode. The charge-discharge current density was 0.5 mA / cm². 2 The initial charge-discharge curve of this all-solid-state battery can be found in [reference needed]. Figure 10 As shown, by Figure 10 It can be seen that the potential of the negative electrode is also too high, and the overall voltage platform of the battery is too low. It is believed that this is due to the low purity of the lithium gallium alloy prepared by the method of this comparative example.

[0070] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0071] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A method for preparing a gallium-based alloy, characterized in that, The preparation method includes: mixing and grinding metallic gallium with other metals selected from metallic gallium to form an alloy, and then annealing the alloy at a temperature of 80-350°C to obtain a pure phase gallium-based alloy. The mixing and grinding and the annealing treatment are carried out under a protective atmosphere. The molar ratio of gallium to the other metals is 0.1-10:1, and the other metals are lithium or sodium.

2. The method for preparing gallium-based alloys according to claim 1, characterized in that, The annealing process is carried out at a temperature of 80-200℃.

3. The method for preparing gallium-based alloys according to claim 1, characterized in that, The annealing time for the annealing process is controlled to be 0.5-2 hours.

4. The method for preparing gallium-based alloys according to claim 1, characterized in that, The protective atmosphere is formed by introducing nitrogen and / or an inert gas.

5. The method for preparing gallium-based alloys according to claim 1, characterized in that, The molar ratio of gallium to the other metals is 0.5-10:

1.

6. A gallium-based alloy prepared by any one of claims 1-5.

7. A gallium-based alloy anode material, characterized in that, The gallium-based alloy anode material comprises the gallium-based alloy as described in claim 6.

8. The gallium-based alloy anode material according to claim 7, characterized in that, This gallium-based alloy anode material also contains inactive substances that do not participate in the lithium deposition reaction.

9. The gallium-based alloy anode material according to claim 8, characterized in that, The inactive substance includes one or more combinations selected from oxides, carbon, and chlorides.

10. The gallium-based alloy anode material according to claim 7, characterized in that, This gallium-based alloy anode material also contains an ionic conductive agent.

11. The application of a gallium-based alloy anode material as described in any one of claims 7-10 as an anode in the preparation of a battery.

12. The application according to claim 11, characterized in that, The battery is a solid-state battery, a liquid battery, or a flow battery.

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