Halogenated lithium borate electrolyte, preparation method thereof and all-solid-state lithium ion battery
A low-temperature synthesis method for lithium boron halide electrolytes addresses the high-pressure and high-temperature challenges of existing methods, producing high-purity electrolytes suitable for industrial use.
Patent Information
- Application Number
- CN202510260605.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-07-15
AI Technical Summary
The existing lithium boronate synthesis process relies on high pressure or high temperature, resulting in high production costs and often accompanied by heterogeneous phases in the products, affecting performance and large-scale applications.
The lithium boric acid and lithium halide are used to prepare lithium boric acid and lithium halide in solvents to prevent high-pressure or high-temperature conditions and improve purity and particle uniformity.
It is achieved to improve the purity and particle size uniformity of lithium boronate halide electrolyte while reducing the sintering temperature, simplify the process flow and reduce production costs, and has good industrialization potential.
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Figure CN120308974A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of batteries, and particularly relates to a lithium borate halide electrolyte, a preparation method thereof, and an all-solid-state lithium-ion battery. Background Art
[0002] With the booming rise of the new energy industry, especially continuous breakthroughs in key fields such as electric vehicles, large-scale energy storage, and micro-devices, the pursuit of battery performance has become increasingly stringent. All-solid-state lithium batteries are recognized as strong competitors for the next-generation energy storage devices due to their excellent high safety, high energy density, and wide temperature adaptability. In this industrial pattern, as the key medium for lithium-ion conduction, the research and innovation of solid electrolytes have become increasingly prominent, becoming the core link in the technological breakthrough of all-solid-state lithium batteries.
[0003] However, many technical problems of all-solid-state lithium batteries need to be solved urgently. The shortcomings of sulfide electrolytes in terms of water and oxygen stability, the interfacial compatibility problem between the cathode and the solid electrolyte, and the bottlenecks of low ionic conductivity and narrow electrochemical window of polymer electrolytes at room temperature all restrict their large-scale application. In contrast, oxide-based solid electrolytes show a broader application prospect due to their natural advantages in stability and safety.
[0004] As an outstanding representative of lithium-ion conductive solid oxides, lithium borate halide has become an ideal candidate material for the practical application of all-solid-state lithium batteries due to its excellent stability in air, water insolubility, and wide electrochemical window. However, most of the existing synthesis processes rely on high-pressure or high-temperature conditions, and there are often impurity phases in the products, which undoubtedly increases the production cost and process complexity, and also affects the further improvement of its performance and the process of large-scale application to a certain extent.
[0005] Therefore, it is necessary to develop a lithium borate halide electrolyte, a preparation method thereof, and an all-solid-state lithium-ion battery to reduce the sintering temperature and improve the purity of lithium borate halide at the same time. Summary of the Invention
[0006] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. Therefore, the present invention provides a lithium borate halide electrolyte, a preparation method thereof, and an all-solid-state lithium-ion battery to reduce the sintering temperature and improve the purity of lithium borate halide at the same time.
[0007] The first aspect of the present invention provides a preparation method of a lithium borate halide electrolyte.
[0008] Specifically, the preparation method of the lithium borate halide electrolyte includes the following steps:
[0009] (1) Dissolve a lithium source in a solvent to obtain solution A; dissolve lithium halide and boric acid in a solvent to obtain solution B;
[0010] (2) Mix the solution A and the solution B, and dry to obtain a powder.
[0011] (3) Heat and sinter the powder to obtain the lithium borate halide electrolyte.
[0012] In step (1), the lithium source includes at least one of metallic lithium and organolithium compounds.
[0013] Preferably, the organolithium compound includes at least one of lithium ethoxide, lithium methoxide, lithium propoxide, and lithium n-butoxide.
[0014] Preferably, in step (1), the molar ratio of the lithium source, boric acid, and lithium halide is (3 - 4):7:(0.1 - 2).
[0015] More preferably, in step (1), the molar ratio of the lithium source, boric acid, and lithium halide is (3 - 4):7:(1 - 2).
[0016] Preferably, in step (1), the lithium halide includes at least one of lithium chloride, lithium bromide, and lithium iodide.
[0017] Preferably, in step (1), stirring is performed during the preparation of the solution A, and the rotation speed of the stirring is 300 - 1000 rpm, and the time is 0.5 - 4 h.
[0018] More preferably, in step (1), stirring is performed during the preparation of the solution A, and the rotation speed of the stirring is 500 - 1000 rpm, and the time is 0.5 - 2 h.
[0019] Preferably, in step (2), the drying method includes at least one of rotary evaporation drying and vacuum drying.
[0020] More preferably, for the rotary evaporation drying, the water bath temperature is 40 - 60 °C, the vacuum degree is 0.1 - 0.5 MPa, and the time is 1 - 6 h.
[0021] Even more preferably, for the rotary evaporation drying, the water bath temperature is 40 - 50 °C, the vacuum degree is 0.1 - 0.2 MPa, and the time is 3 - 6 h.
[0022] More preferably, for the vacuum drying, the temperature is 70 - 100 °C, and the time is 3 - 10 h.
[0023] Even more preferably, for the vacuum drying, the temperature is 80 - 100 °C, and the time is 5 - 10 h.
[0024] Preferably, in step (3), the temperature of the heat sintering is 400 - 750 °C.
[0025] Further preferably, in step (3), the temperature of the heat sintering is 550 - 650 °C.
[0026] Even more preferably, in step (3), the temperature of the heat sintering is 600 °C.
[0027] If the sintering temperature is lower than 400 °C, the formation of multiple lithium borate heterophases may be caused; if the sintering temperature is higher than 750 °C, the lithium borate halide particles will melt, thereby causing an increase in particle size.
[0028] Preferably, in step (3), the heat preservation time corresponding to the heat sintering is 1 - 6 h.
[0029] Further preferably, in step (3), the heat preservation time corresponding to the heat sintering is 2 - 4 h.
[0030] The second aspect of the present invention provides a lithium borate halide electrolyte.
[0031] Specifically, the lithium borate halide electrolyte is prepared by the preparation method provided in the first aspect.
[0032] Preferably, the chemical formula of the lithium borate halide electrolyte is Li 4+x B7O 12+x / 2 Y;
[0033] where Y represents at least one of chlorine, bromine, and iodine, and the value range of x is 0 - 2.
[0034] Further preferably, the lithium borate halide electrolyte includes Li4B7O 12 Cl, Li5B7O 12.5 Cl, Li4B7O 12 Br, Li5B7O 12.5 Br.
[0035] The third aspect of the present invention provides a all - solid - state lithium - ion battery.
[0036] Specifically, the all - solid - state lithium - ion battery includes the lithium borate halide electrolyte provided in the second aspect.
[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0038] The present invention adopts a method of co - precipitation of a lithium source, boric acid and lithium halide in a solvent. Without the need for high - pressure or high - temperature conditions, a lithium borate halide precursor with uniform composition can be prepared, and then a lithium borate halide electrolyte can be efficiently synthesized. Compared with the traditional preparation process, the lithium borate halide electrolyte prepared by this method shows significant superiority in terms of purity and particle size. In addition, the process flow is simple to operate, environmentally friendly, and has good potential for industrial implementation. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Figure 1 It is the X - ray diffraction pattern of the electrolyte material prepared in Example 2;
[0040] Figure 2 It is the Rietveld refinement of the XRD pattern of the electrolyte material prepared in Example 2;
[0041] Figure 3 It is the scanning electron microscope image of the electrolyte material prepared in Example 2;
[0042] Figure 4 It is the scanning electron microscope image of the electrolyte material prepared in Comparative Example 1;
[0043] Figure 5 It is the X - ray diffraction pattern of the electrolyte materials prepared in Comparative Example 1 and Comparative Example 2. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0044] In order to make the technical solutions described in the present invention clearer and more understandable to those skilled in the art, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.
[0045] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels or can be obtained by existing known methods.
[0046] Example 1
[0047] A method for preparing a lithium borate halide electrolyte, comprising the following steps:
[0048] Under a dry air atmosphere, lithium ethoxide, boric acid, and lithium chloride were weighed at a molar ratio of 3:7:1 (weighed according to a total raw material weight of 10 g); lithium ethoxide was placed into a glass bottle with a lid, 30 mL of absolute ethanol was added, a magnetic stirrer was added, and it was stirred at 500 rpm for 0.5 h. After the raw materials were dissolved, solution A was obtained; H3BO3 and LiCl were weighed according to the material ratio and placed into a glass bottle with a lid, 60 mL of absolute ethanol was added, a magnetic stirrer was added, and it was stirred at 500 rpm for 0.5 h. After the raw materials were completely dissolved, solution B was obtained; solution A was slowly added to solution B, and stirring was continued for 2 h to form a white suspension; the ethanol solvent in the suspension was preliminarily removed by rotary evaporation. The water bath temperature for rotary evaporation was 50 °C, the vacuum degree was 0.1 MPa, and the rotary evaporation time was 3 h. The material was scraped out from the rotary evaporation flask and vacuum dried at 80 °C for 5 h; the dried material was transferred to an alumina crucible, heated to 600 °C and kept warm for 2 h; after the reaction ended and cooled to room temperature, Li4B7O 12 Cl electrolyte powder could be obtained.
[0049] Example 2
[0050] Preparation method of lithium borate halide electrolyte.
[0051] The difference from Example 1 was that the molar ratio of lithium ethoxide, boric acid, and lithium chloride was adjusted to 4:7:1, and the rest of the preparation steps were the same as those in Example 1. Li5B7O 12.5 Cl electrolyte powder was prepared.
[0052] Example 3
[0053] Preparation method of lithium borate halide electrolyte.
[0054] The difference from Example 1 was that lithium chloride was replaced with lithium bromide, and the rest of the preparation steps were the same as those in Example 1. Li4B7O 12 Br electrolyte powder was prepared.
[0055] Example 4
[0056] Preparation method of lithium borate halide electrolyte.
[0057] The difference from Example 3 was that the molar ratio of lithium ethoxide, boric acid, and lithium bromide was adjusted to 4:7:1, and the rest of the preparation steps were the same as those in Example 1. Li5B7O 12.5 Br electrolyte powder was prepared.
[0058] Example 5
[0059] Preparation method of lithium borate halide electrolyte, including the following steps:
[0060] In a dry air atmosphere, lithium metal, boric acid, and lithium chloride were weighed in a molar ratio of 4:7:1. The lithium metal was placed in a glass bottle with a lid, and 40 mL of absolute ethanol was added. After the lithium metal reacted with ethanol and was allowed to stand and cool, solution A was obtained; H3BO3 and LiCl were weighed according to the material ratio and placed in a glass bottle with a lid. 60 mL of absolute ethanol was added, and a magnetic stirrer was added and stirred at 500 rpm for 0.5 h. After the raw materials were completely dissolved, solution B was obtained; solution A was slowly added to solution B and continuously stirred for 2 h to form a white suspension; the ethanol solvent in the suspension was initially removed by rotary evaporation. The water bath temperature for rotary evaporation was 50 °C, the vacuum degree was 0.1 MPa, and the rotary evaporation time was 3 h; the material was scraped out of the rotary evaporation flask and dried in vacuo at 80 °C for 5 h; the dried material was transferred to an alumina crucible, heated to 500 °C and held for 3 h; after the reaction ended and cooled to room temperature, Li5B7O 12.5 Cl electrolyte powder was obtained.
[0061] Comparative Example 1
[0062] Preparation method of lithium borate halide electrolyte.
[0063] The difference from Example 2 was that lithium nitrate was used instead of lithium ethoxide, and the remaining preparation steps were the same as those in Example 2. Li5B7O 12.5 Cl electrolyte powder was obtained.
[0064] Comparative Example 2
[0065] Preparation method of lithium borate halide electrolyte, the specific steps are as follows:
[0066] Lithium hydroxide, boric acid, and lithium chloride were accurately weighed in a molar ratio of 4:7:1 and placed in a zirconia ball milling jar; a ball-to-material mass ratio of 40:1 was used, and ball milling was carried out at a rotation speed of 500 rpm / min for 10 h to ensure the mixing of raw materials; after ball milling was completed, the mixed material was transferred to an alumina crucible, heated to 800 °C and held for 2 h; after the reaction was completed, it was naturally cooled to room temperature, and finally Li5B7O 12.5 Cl electrolyte powder was obtained.
[0067] Performance testing:
[0068] X-ray diffraction analysis and scanning electron microscope detection were carried out on the lithium borate halide electrolytes prepared in Example 2 and Comparative Examples 1-2.
[0069] Figure 1 The X-ray diffraction (XRD) pattern of the electrolyte material prepared in Example 2 is shown. The ordinate intensity is the intensity, and its diffraction curve is highly consistent with the standard card, and no other obvious impurity peaks appear, indicating that the product has good purity and crystallinity. For further quantitative analysis of Li5B7O12.5 The mass percentage of Cl phase was refined by XRD results. The refined results are shown in Figure 2 As shown. After refined calculation, the final product contains Li5B7O 12.5 The mass proportion of Cl is as high as 99.6%, while the impurity content is only 0.4%. Li5B7O prepared in Example 2 12.5 The surface morphology of Cl electrolyte powder is as follows Figure 3 As shown in the figure, the particles are spherical with a diameter of 200 to 600 nm. These particles can directly form oxide solid electrolyte particles with regular shape and uniform particle size without further refinement or screening, showing excellent microstructural properties.
[0070] Comparative Example 1: Li5B7O prepared using lithium nitrate 12.5 The Cl electrolyte material exhibits a larger particle size after sintering, e.g. Figure 4 As shown, the average particle size of the particles reaches 10 μm, which is significantly higher than the sample prepared using lithium ethoxide in Example 2. The X-ray diffraction (XRD) test results of Comparative Example 1 are shown in Figure 5 As shown in the figure, it shows that there is a Li2B4O7 impurity phase in the product. After XRD refinement calculation, the final product contains Li5B7O 12.5 The mass proportion of Cl is only 64.7%. In contrast, the sample prepared using lithium ethoxide has a higher material purity, which indicates that lithium nitrate is more suitable for preparing Li5B7O 12.5 When the reaction path and product purity are not as good as those of lithium ethoxide, the X-ray diffraction (XRD) test results of Comparative Example 2 are as follows: Figure 5 As shown, it shows that there are more LiBO2 impurities in the product. After XRD refinement calculation, the final product contains Li5B7O 12.5 The mass proportion of Cl is only 75.6%. In comparison, the material prepared in Example 2 has a higher purity.
[0071] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution obtained by any modification, equivalent replacement, improvement, etc. made by a person skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection determined by the claims.
Claims
1. A method for preparing a lithium borate halide electrolyte, characterized in that, It includes the following steps: (1) Dissolve a lithium source in a solvent to obtain solution A; dissolve lithium halide and boric acid in a solvent to obtain solution B; (2) Mix the solution A and the solution B, and dry to obtain a powder; (3) Heat and sinter the powder to obtain the lithium borate halide electrolyte; In step (1), the lithium source includes at least one of metallic lithium and organolithium compounds.
2. The preparation method according to claim 1, characterized in that, The organolithium compound includes at least one of lithium ethoxide, lithium methoxide, lithium propoxide, and lithium n-butoxide.
3. The preparation method according to claim 1, wherein In step (1), the molar ratio of the lithium source, boric acid, and lithium halide is (3-4):7:(0.1-2).
4. The preparation method according to claim 1, characterized in that, In step (1), the lithium halide includes at least one of lithium chloride, lithium bromide, and lithium iodide.
5. The preparation method according to claim 1, characterized in that, In step (1), stirring is performed during the preparation of solution A, and the rotation speed of the stirring is 300-1000 rpm, and the time is 0.5-4 h.
6. The preparation method according to claim 1, characterized in that, In step (2), the drying method is at least one of rotary evaporation drying and vacuum drying.
7. The preparation method according to claim 1, wherein In step (3), the temperature of the heat sintering is 400-750 °C.
8. The preparation method according to claim 1, characterized in that, In step (3), the heat preservation time corresponding to the heat sintering is 1-6 h.
9. A lithium borate halide electrolyte, characterized in that, The lithium borate halide electrolyte is prepared by the preparation method according to any one of claims 1 to 8.
10. A all-solid-state lithium-ion battery, characterized in that, The all-solid-state lithium-ion battery includes the lithium borate halide electrolyte according to claim 9.