Gallium-based alloy, preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a gallium-based alloy, a preparation method therefor and a use thereof. The preparation method comprises: mixing and grinding metal gallium and one or more of metals other than the metal gallium to form an alloy, and then carrying out annealing treatment at a temperature of 30-400°C. When being used for preparing a negative electrode and being further applied to a battery, the gallium-based alloy prepared by the method can suppress the continuous growth of negative electrode dendrites in the battery, so that uniform deposition of ions is realized, the contact area of an electrode and an electrolyte is increased, the critical current density is improved, and the heat dissipation of the battery is accelerated, and thus the safety is improved, thereby improving the cycle performance of the battery. The problem of short cycle life of the metal secondary battery is effectively solved. Moreover, the method is simple and effective, and has simple and convenient process, high efficiency, and mild conditions.

Description

A gallium-based alloy and its preparation method and application Technical Field

[0001] The present invention relates to the field of electrochemical devices, and in particular to a gallium-based alloy and a preparation method and application thereof. Background Art

[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 energy strategy for various countries. Energy storage devices, represented by metal secondary batteries such as lithium metal batteries and sodium metal batteries, play an extremely important role in energy storage and conversion. Metallic lithium and metallic sodium are considered to be preferred materials that can significantly improve battery energy density due to their high specific capacity and low electrode potential. However, metallic lithium and sodium negative electrodes continuously form dendrites during battery cycling, which continuously consumes electrolyte, resulting in low battery coulombic efficiency and reduced cycle life. More seriously, the continued growth of dendrites can pierce the diaphragm, causing an internal short circuit in the battery. The accumulated heat can easily cause battery safety accidents. Summary of the Invention

[0003] The purpose of the present invention is to overcome one or more deficiencies in the prior art and to provide an improved method for preparing a gallium-based alloy. When the gallium-based alloy prepared by this method is used to make a negative electrode and applied to a battery, it can inhibit the continued growth of negative electrode dendrites in the battery, accelerate the heat dissipation of the battery, and provide a highly safe and uniformly ion-deposited negative electrode while improving the cycle performance of the battery.

[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 negative electrode material comprising the gallium-based alloy prepared by the above method and use of the gallium-based alloy negative electrode material as a negative electrode in preparing a battery.

[0006] To achieve the above-mentioned object, the present invention adopts a technical solution: a method for preparing a gallium-based alloy, which comprises: mixing and grinding metallic gallium with one or more metals selected from other metals other than the metallic gallium, and then annealing the alloy at a temperature of 30-400°C.

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

[0008] In some embodiments of the present invention, the annealing treatment is carried out at a temperature 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 treatment is controlled to be 0.2-8 hours. Further, the annealing time of the annealing treatment is controlled to be 0.5-2 hours, for example, 0.5 hours, 0.6 hours, 0.8 hours, 1 hour, 1.5 hours, 1.8 hours, etc.

[0010] According to some preferred aspects of the present invention, the mixing and grinding and the annealing treatment are respectively carried out under a protective atmosphere, wherein the protective atmosphere is formed by introducing nitrogen and / or an inert gas. Further, the inert gas includes but is not limited to helium, argon, etc.

[0011] According to some preferred aspects of the present invention, the other metals include but are not limited to one or a combination of two or more 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 the present invention, after lithium ions obtain 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 and other metals is more conducive to forming a path for lithium diffusion, which in turn helps to inhibit the formation of dendrites on the negative electrode surface. According to some preferred aspects of the present invention, the molar ratio of the metallic gallium to the other metals is 0.1-10:1, for example, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, 1:1, 1.2:1, 1.3:1, 1.5:1, 1.6:1, 1.8:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

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

[0014] In some embodiments of the present invention, the molar ratio of the metallic gallium to the other metals is 0.5-5:1.

[0015] In some preferred embodiments of the present invention, the process for preparing the gallium-based alloy includes:

[0016] Under a protective atmosphere, mixing and grinding metallic gallium with one or more metals selected from other metals other than the metallic gallium until they are completely fused to form an alloy;

[0017] Then, the alloy obtained by grinding is annealed at a temperature of 30-400° C. under a protective atmosphere and kept warm.

[0018] Another technical solution provided by the present invention is a gallium-based alloy prepared by the above-mentioned preparation method of the gallium-based alloy.

[0019] Another technical solution provided by the present invention is a gallium-based alloy negative electrode material, which comprises the gallium-based alloy described above.

[0020] In the present invention, the gallium-based alloy negative electrode material may be composed solely of a gallium-based alloy, or may further contain 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 a combination of one or more selected from oxides (for example, magnesium oxide, calcium oxide, zirconium oxide, etc.), carbon, and chlorides (for example, magnesium chloride, calcium chloride, sodium chloride, etc.).

[0021] In some embodiments of the present invention, the gallium-based alloy negative electrode material further comprises an ion conductor (e.g., a halide electrolyte, a sulfide electrolyte, an oxide electrolyte, etc.). For example, when used in a solid-state battery, the gallium-based alloy described above can be mixed with the ion conductor to form an electrode material, wherein the type and content of the ion conductor can be regulated and selected according to different battery systems.

[0022] Another technical solution provided by the present invention is a method for preparing a gallium-based alloy negative electrode material, the method comprising: mixing and grinding metallic gallium with one or more metals selected from other metals other than the metallic gallium, forming an alloy, and then annealing the alloy at a temperature of 30-400°C;

[0023] The annealed gallium-based alloy is then left to stand, cooled, and pressed to obtain the lithium-gallium alloy negative electrode material.

[0024] Furthermore, the standing time may be 0.1-10 h, for example, 0.2-8 h, or 0.5-5 h.

[0025] Another technical solution provided by the present invention is the use of the gallium-based alloy negative electrode material described above as a negative electrode in the preparation of a battery.

[0026] In some embodiments of the present invention, the battery includes various batteries such as solid-state batteries, liquid batteries, or flow batteries;

[0027] Among them, solid-state batteries are batteries that use solid electrodes and solid electrolytes. Solid-state batteries generally have lower power density and higher energy density. Solid-state batteries include but are not limited to lithium batteries, sodium batteries, magnesium batteries, calcium batteries, potassium batteries, etc.

[0028] A liquid battery consists of a cell consisting of electrochemically active electrodes immersed in a glass container filled with an electrolyte;

[0029] A flow battery consists of a stack unit, electrolyte, electrolyte storage and supply unit, and management and control unit. A flow battery is a high-performance storage battery that utilizes separate, circulating positive and negative electrolytes. It boasts high capacity, wide application range (environmental), and long cycle life. Flow batteries achieve the conversion of electrical energy into chemical energy through reversible redox reactions (i.e., reversible changes in valence) of active substances in the positive and negative electrolyte solutions. During charging, an oxidation reaction occurs at the positive electrode, increasing the valence of the active substance, while a reduction reaction occurs at the negative electrode, decreasing the valence of the active substance. The discharge process is the reverse.

[0030] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0031] After extensive experimental research, the inventors of the present invention discovered that, when preparing gallium-based alloys, they first grind the various metals to form an alloy, and then anneal it in a relatively low specific temperature range. They found that a pure-phase gallium-based alloy can be obtained, and that this alloy can effectively inhibit the growth of dendrites at the negative electrode, with an unexpected inhibitory effect, achieving uniform ion deposition, reducing battery safety risks, improving battery safety, and enhancing battery cycle performance. In practice, it has been found that when the gallium-based alloy prepared by the present invention is applied to the negative electrode of a lithium battery, the critical current density of the battery, such as an all-solid-state battery, can reach 10 mA / cm 2 Above, and can stably cycle more than 500 times;

[0032] Furthermore, after research and analysis by the inventors, it is believed that the gallium-based alloy prepared by the method of the present invention has a relatively low chemical potential and can enable alkali metal ions to form alloys or solid solutions when deposited at the negative electrode, thereby effectively inhibiting the growth of negative electrode dendrites, increasing the electrode-electrolyte contact area, and improving the critical current density of the battery, thereby providing a high level of safety and uniform ion deposition while improving the cycle life of the battery.

[0033] In addition, the present invention not only effectively solves the problem of short cycle life of metal secondary batteries, but also has a simple and effective method, simple process, high efficiency and mild conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is an X-ray diffraction spectrum of the lithium-gallium alloy prepared in Example 1 of the present invention;

[0035] FIG2 is the first charge and discharge curve of the all-solid-state battery prepared in Example 1 of the present invention (commercial high-nickel ternary NCM811 as the positive electrode);

[0036] FIG3 is a cycle performance test diagram of the all-solid-state battery prepared in Example 1 of the present invention (commercial high-nickel ternary NCM811 as the positive electrode);

[0037] FIG4 is a constant current charge and discharge test diagram of an all-solid-state symmetrical battery prepared in Example 1 of the present invention;

[0038] FIG5 is a charge and discharge curve of the all-solid-state battery (metal lithium as the counter electrode) prepared in Example 2 of the present invention;

[0039] FIG6 is an X-ray diffraction spectrum of the lithium-gallium alloy prepared in Comparative Example 1 of the present invention;

[0040] FIG7 is the first charge and discharge curve of the all-solid-state battery prepared in Comparative Example 1 of the present invention (commercial high-nickel ternary NCM811 as the positive electrode);

[0041] FIG8 is the first charge and discharge curve of the all-solid-state battery prepared in Comparative Example 2 of the present invention (commercial high-nickel ternary NCM811 as the positive electrode);

[0042] FIG9 is an X-ray diffraction spectrum of the lithium-gallium alloy prepared in Comparative Example 3 of the present invention;

[0043] FIG10 is the first charge and discharge curve of the all-solid-state battery prepared in Comparative Example 4 of the present invention (commercial high-nickel ternary NCM811 as the positive electrode). DETAILED DESCRIPTION

[0044] The above scheme is further described below in conjunction with specific examples; it should be understood that these examples 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 examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are generally the conditions in routine experiments.

[0045] Unless otherwise specified in the following examples, all raw materials were purchased from commercial sources or prepared by conventional methods in the art. Example 1

[0046] This embodiment provides a lithium-gallium alloy and a preparation method thereof, and a further prepared lithium-gallium alloy negative electrode material.

[0047] The preparation method of the lithium-gallium alloy comprises:

[0048] 0.7g of gallium metal and 0.1g of lithium metal were weighed separately and manually ground in an agate mortar in a glove box until they were completely fused together to form an alloy. The ground materials were then annealed in an argon atmosphere at 180°C for 2h to form a Li3Ga2 alloy. The X-ray diffraction spectrum of the alloy is shown in Figure 1.

[0049] The Li3Ga2 alloy obtained after the above heat preservation was allowed to stand, cooled and pressed, and the standing time was 1 hour to obtain a lithium gallium alloy negative electrode material.

[0050] The lithium-gallium alloy negative electrode material obtained in this example was assembled into an all-solid-state battery and subjected to constant current charge and discharge tests. The lithium-gallium alloy negative electrode material obtained in this example was used as the negative electrode, Li6PS5Cl was used as the electrolyte, and commercial high-nickel ternary was used as the positive electrode. The charge and discharge current density was 0.5 mA / cm 2 The first charge and discharge curve of the all-solid-state battery is shown in Figure 2. As shown in Figure 2, the average voltage of the all-solid-state battery is around 3.8V, which is the normal operating voltage value of the high-nickel ternary positive electrode, and the battery cycle performance is good. As shown in Figure 3, after 500 cycles, the capacity retention rate is still very high, with almost no decline, and the retention rate is above 98%.

[0051] The lithium-gallium alloy negative electrode material obtained in this example was assembled into an all-solid-state symmetrical battery and subjected to constant current charge and discharge tests. As shown in Figure 4, the battery 2 It can still cycle stably at a current density of 10 mA / cm 2 above. Example 2

[0052] This embodiment provides a sodium-gallium alloy, a preparation method thereof, and a further prepared sodium-gallium alloy negative electrode material.

[0053] The preparation method of the sodium gallium alloy comprises:

[0054] 0.7g of gallium metal and 0.33g of sodium metal were weighed separately and manually ground with an agate mortar in a glove box until they were completely fused together to form an alloy. The ground materials were then annealed in an argon atmosphere at a temperature of 120°C and kept warm for 2h to form a Na3Ga2 alloy.

[0055] The Na3Ga2 alloy obtained after the above heat preservation was allowed to stand, cooled and pressed, and the standing time was 1 hour to obtain a sodium gallium alloy negative electrode material.

[0056] The sodium gallium alloy negative electrode material obtained in this example was assembled into an all-solid-state battery and subjected to constant current charge and discharge tests, wherein metallic sodium was used as the counter electrode, Na3PS4 was used as the electrolyte, and the sodium gallium alloy negative electrode material obtained in this example was used as the working electrode. The charge and discharge current was 3 mA / cm 2 The charge and discharge time is set to 1h. The charge and discharge curve of the all-solid-state battery is shown in Figure 5. It can be seen from the figure that the sodium insertion potential of the battery is less than 0.3V, indicating that the negative electrode can well exhibit a lower potential when used in sodium batteries. Comparative Example 1

[0057] This comparative example provides a lithium-gallium alloy and a preparation method thereof, and a further prepared lithium-gallium alloy negative electrode material.

[0058] The preparation method of the lithium-gallium alloy comprises:

[0059] 0.7g of gallium metal and 0.1g of lithium metal were mixed and heated directly under argon atmosphere at a temperature of 800℃ for 2h to form Li x Ga y Figure 6 shows the Li alloy prepared in this comparative example 1. x Ga y The X-ray diffraction spectrum of the alloy shows that the lithium-gallium alloy prepared by this method has obvious impurity phase.

[0060] The Li x Ga y The alloy block was allowed to stand, cooled, ground into powder and pressed, and the standing time was 1 hour to obtain a lithium gallium alloy negative electrode material.

[0061] The lithium-gallium alloy negative electrode material obtained in this comparative example 1 was assembled into an all-solid-state battery and a charge-discharge test was performed, wherein the lithium-gallium alloy negative electrode material in this comparative example 1 was used as the negative electrode, Li6PS5Cl was used as the electrolyte, and commercial high-nickel ternary was used as the positive electrode. The current density was 0.5 mA / cm 2The first charge and discharge curve of the all-solid-state battery is shown in Figure 7. It is found that the potential of the negative electrode is too high and the voltage platform of the overall battery is too low. Analysis shows that this is probably caused by the large amount of impurities in the lithium-gallium alloy. Comparative Example 2

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

[0063] The lithium-gallium alloy negative electrode material obtained in this comparative example 2 was assembled into an all-solid-state battery and subjected to a constant current charge and discharge test, wherein the lithium-gallium alloy negative electrode material obtained in this comparative example 2 was used as the negative electrode, Li6PS5Cl was used as the electrolyte, and commercial high nickel ternary was used as the positive electrode. The charge and discharge current density was 0.5 mA / cm 2 The first charge and discharge curve of the all-solid-state battery is shown in FIG8 . As can be seen from FIG8 , the potential of the negative electrode is also relatively high, and the voltage platform of the overall battery is relatively low. Analysis shows that this is probably due to the insufficient purity of the lithium-gallium alloy obtained by the method of comparative example 2. There should be more impurities, which in turn affects the electrical performance. Comparative Example 3

[0064] The process is basically the same as Example 1, with the only difference being that the annealing temperature is 420°C.

[0065] The X-ray diffraction spectrum of the lithium-gallium alloy obtained in this comparative example 3 is shown in FIG9 . As can be seen from FIG9 , a phase of pure lithium metal appears, indicating that the lithium-gallium alloy prepared by the method in this comparative example also has obvious impurity phases, and the purity of the obtained lithium-gallium alloy is obviously not high. Comparative Example 4

[0066] The method is basically the same as Example 1, with the only difference being that the order of grinding and annealing is adjusted, specifically, heating and melting at 180° C. is performed first, and then grinding is performed.

[0067] The lithium-gallium alloy negative electrode material obtained in this control example was assembled into an all-solid-state battery and subjected to a constant current charge and discharge test. The lithium-gallium alloy negative electrode material obtained in this control example was used as the negative electrode, Li6PS5Cl was used as the electrolyte, and commercial high-nickel ternary was used as the positive electrode. The charge and discharge current density was 0.5 mA / cm 2 The first charge and discharge curve of the all-solid-state battery is shown in FIG10 . As can be seen from FIG10 , the potential of the negative electrode is also relatively high, and the voltage platform of the overall battery is relatively low. Analysis shows that this is due to the low purity of the lithium-gallium alloy prepared by the method of this control example.

[0068] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

[0069] The endpoints of the ranges and any values ​​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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

Claims

1. A method for preparing a gallium-based alloy, characterized in that: The preparation method comprises: mixing and grinding metal gallium with one or more metals selected from other metals except the metal gallium under a protective atmosphere until they are completely fused to form an alloy; Then, the alloy obtained by grinding is annealed at a temperature of 30-400° C. under a protective atmosphere and kept warm; The annealing time of the annealing treatment is controlled to be 0.2-8h, and the other metals include one or a combination of two or more selected from lithium, sodium, potassium, calcium, magnesium, indium, iron, copper, manganese, gold, silver, zinc, platinum, cobalt, tin, nickel, antimony, ruthenium, aluminum, titanium, and tungsten; and the molar ratio of the metal gallium to the other metals is 0.1-10:

1.

2. A method for preparing a gallium-based alloy, characterized in that: The preparation method comprises: mixing and grinding metal gallium with one or more metals selected from other metals except the metal gallium, forming an alloy and then performing annealing treatment at a temperature of 30-400°C.

3. The method for preparing a gallium-based alloy according to claim 2, characterized in that: The annealing treatment is performed at a temperature of 50-350°C.

4. The method for preparing a gallium-based alloy according to claim 3, characterized in that: The annealing treatment is performed at a temperature of 80-200°C.

5. The method for preparing a gallium-based alloy according to claim 2, characterized in that: The annealing time of the annealing treatment is controlled to be 0.2-8h.

6. The method for preparing a gallium-based alloy according to claim 5, characterized in that: The annealing time of the annealing treatment is controlled to be 0.5-2h.

7. The method for preparing a gallium-based alloy according to claim 2, characterized in that: The mixed grinding and the annealing treatment are respectively performed under a protective atmosphere, and the protective atmosphere is formed by introducing nitrogen and / or an inert gas.

8. The method for preparing a gallium-based alloy according to claim 2, characterized in that: The other metals include one or a combination of two or more selected from lithium, sodium, potassium, calcium, magnesium, indium, iron, copper, manganese, gold, silver, zinc, platinum, cobalt, tin, nickel, antimony, ruthenium, aluminum, titanium, and tungsten.

9. The method for preparing a gallium-based alloy according to claim 2, characterized in that: The molar ratio of the metal gallium to the other metals is 0.1-10:

1.

10. The method for preparing a gallium-based alloy according to claim 9, characterized in that: The molar ratio of the metal gallium to the other metals is 0.2-10:

1.

11. The method for preparing a gallium-based alloy according to claim 10, characterized in that: The feeding molar ratio of the metal gallium to the other metals is 0.5-10:

1.

12. The method for preparing a gallium-based alloy according to claim 11, characterized in that: The molar ratio of the metal gallium to the other metals is 0.5-5:

1.

13. The method for preparing a gallium-based alloy according to claim 2, characterized in that: The method of preparing the gallium-based alloy includes: Under a protective atmosphere, mixing and grinding metal gallium with one or more metals selected from other metals other than the metal gallium until they are completely fused to form an alloy; Then, the alloy obtained by grinding is annealed at a temperature of 30-400° C. under a protective atmosphere and kept warm.

14. A gallium-based alloy prepared by the method for preparing a gallium-based alloy according to any one of claims 1 to 13.

15. A gallium-based alloy negative electrode material, characterized in that: The gallium-based alloy negative electrode material comprises the gallium-based alloy according to claim 14.

16. The gallium-based alloy negative electrode material according to claim 15, characterized in that: The gallium-based alloy negative electrode material also contains inactive substances that do not participate in the lithium deposition reaction.

17. The gallium-based alloy negative electrode material according to claim 16, characterized in that: The inactive substance includes one or more selected from oxides, carbon, and chlorides.

18. The gallium-based alloy negative electrode material according to claim 17, characterized in that: The oxide includes a combination of one or more selected from magnesium oxide, calcium oxide, and zirconium oxide; the chloride includes a combination of one or more selected from magnesium chloride, calcium chloride, and sodium chloride.

19. The gallium-based alloy negative electrode material according to claim 15, characterized in that: The gallium-based alloy negative electrode material further comprises an ion conductive agent.

20. The gallium-based alloy negative electrode material according to claim 19, characterized in that: The ion conductive agent includes a combination of one or more selected from the group consisting of a halide electrolyte, a sulfide electrolyte, and an oxide electrolyte.

21. Use of the gallium-based alloy negative electrode material according to any one of claims 15 to 20 as a negative electrode in preparing a battery.

22. The use according to claim 21, characterized in that The battery is a solid-state battery, a liquid battery or a flow battery.

23. The use according to claim 22, characterized in that The solid-state battery includes a lithium battery, a sodium battery, a magnesium battery, a calcium battery or a potassium battery.

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