A method for preparing anhydrous lithium iodide
By metathesis reaction of potassium iodide, organic solvent and lithium tetrafluoroborate under protective atmosphere and light-proof conditions, the problem of crystallization water in the preparation of anhydrous lithium iodide is solved, and the preparation of anhydrous lithium iodide with high purity and high yield is achieved.
Patent Information
- Application Number
- CN202411779228.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-05
- Publication Date
- 2025-04-01
AI Technical Summary
In the existing preparation methods for anhydrous lithium iodide, the product contains crystal water, which leads to increased process difficulty, high cost and high impurity content.
Under the protective atmosphere and light-proof conditions, potassium iodide, organic solvent and lithium tetrafluoroborate were mixed to undergo metathesis reaction to produce a crude product of anhydrous lithium iodide, and high-purity anhydrous lithium iodide was obtained through subsequent filtration, distillation and drying steps.
It avoids the generation of crystallization water, reduces process difficulty and preparation cost, and improves the purity and yield of the product.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of energy storage batteries, and particularly relates to a method for preparing anhydrous lithium iodide. Background Art
[0002] Anhydrous lithium iodide is a white solid with a density of 4.076 g / cm 3 , melting point 449℃, boiling point 1171℃, flash point 1170℃~1190℃, easily soluble in water, methanol, ethanol, and acetone, and is corrosive to glass and ceramics when melted.
[0003] The current synthesis methods of anhydrous lithium iodide can be divided into the following three types.
[0004] The first is the neutralization method: lithium carbonate or lithium hydroxide hydrate is used as the raw material to react with hydroiodic acid. This method does not produce any waste, but the resulting product is lithium iodide trihydrate. The dehydration process of this method does not have organic solvents or gas protection. If air enters the disperser at high temperature, the product is easily oxidized and deteriorated, and the sealing and operation requirements of the dispersion process are high. At the same time, this method adopts direct evaporation drying method, without impurity removal process, and has high requirements on the quality and cost of raw materials.
[0005] The second method is to mix water, elemental iodine particles and excess iron powder, add lithium hydroxide, separate the solid and liquid, and obtain lithium iodide solid containing crystal water. Then, the lithium iodide solid is dissolved in an organic solvent and electrolyzed at a constant voltage to obtain anhydrous lithium iodide solid.
[0006] The third method is the liquid ammonia method: ammonium iodide and metallic lithium are reacted in liquid ammonia to prepare lithium iodide to obtain a crystalline hydrate of lithium iodide, and then the crystalline hydrate of lithium iodide is dried in a hydrogen iodide atmosphere, while being heated to melt and dry hydrogen is introduced to remove the iodine left by the hydrogen iodide; or the crystalline hydrate is heated in a vacuum to dehydrate and sublime.
[0007] The water content of lithium iodide obtained by the latter two methods is generally greater than 0.02%, the synthesis process is complicated, the process conditions are harsh, the operation is difficult to control, the cost is high, and the harmful gases in the synthesis process are not recovered and treated, which pollutes the environment.
[0008] The lithium iodide products produced by the above three preparation methods all contain crystal water. Removing the crystal water increases the difficulty of the process, increases the preparation cost, and the impurity content of the product is high.
[0009] Therefore, the industry urgently needs to find a simple and efficient method for synthesizing high-purity anhydrous lithium iodide. Summary of the invention
[0010] In view of the problem that existing anhydrous lithium iodide products contain crystal water, the removal of crystal water increases the process difficulty, increases the preparation cost, and the impurity content of the product is high, the present application provides a method for preparing anhydrous lithium iodide.
[0011] The technical solution adopted by the present invention to solve the above technical problems is as follows: The present invention provides a method for preparing anhydrous lithium iodide, comprising the following steps: In a protective atmosphere and light-proof conditions, potassium iodide, an organic solvent and lithium tetrafluoroborate are mixed and reacted to obtain anhydrous lithium iodide crude product, which is then post-treated to obtain anhydrous lithium iodide.
[0012] Preferably, the organic solvent includes one or more of an ether organic solvent and an alcohol organic solvent.
[0013] Preferably, the ether organic solvent includes one or more of ethylene glycol dimethyl ether, diethyl ether, 1,4-dioxane, and tetrahydrofuran; the alcohol organic solvent includes one or more of anhydrous ethanol and ethylene glycol.
[0014] Preferably, the organic solvent is anhydrous ethanol.
[0015] Preferably, the mass of the organic solvent is m 1 The mass of the potassium iodide and the lithium tetrafluoroborate is m 2 , m 1 :m 2 It is (4~6):1.
[0016] Preferably, the molar ratio of the potassium iodide to the lithium tetrafluoroborate is 1:1.
[0017] Preferably, obtaining anhydrous lithium iodide through post-treatment comprises the following steps: Filtration, distillation and drying are performed in sequence to obtain anhydrous lithium iodide.
[0018] Preferably, the filtration comprises the following steps: filtering to obtain a supernatant liquid under the conditions of a protective atmosphere, avoiding light and a temperature t of -10°C to 10°C.
[0019] Preferably, the distillation comprises the following steps: under a protective atmosphere and light-proof conditions, subjecting the supernatant to reduced-pressure rotary evaporation to obtain a crude lithium iodide product; The drying comprises the following steps: drying the crude lithium iodide under a protective atmosphere and light-proof conditions to obtain the anhydrous lithium iodide.
[0020] Preferably, the distillation temperature of the vacuum rotary evaporation is 40-60°C; The drying temperature is 40~70℃ and the drying time is 3~4h.
[0021] Preferably, potassium iodide, an organic solvent and lithium tetrafluoroborate are mixed and reacted to generate potassium tetrafluoroborate solid and anhydrous lithium iodide, the reaction temperature is 0-30° C., and the reaction time is 1-2 h.
[0022] Compared with the existing method for preparing lithium iodide, the method for preparing anhydrous lithium iodide provided by the present application adopts a double decomposition reaction to synthesize anhydrous lithium iodide. The double decomposition reaction avoids the presence of crystal water in the generated lithium iodide product, which makes it unnecessary to use vacuum and high temperature conditions during post-treatment, reducing the process difficulty; and avoiding high temperature conditions, which also prevents the product from being decomposed and oxidized by high temperature, thereby improving the purity of the product and improving the product yield; the double decomposition reaction is used to prepare anhydrous lithium iodide, and no crystal water is produced, and there is no need to remove the crystal water, thereby reducing the preparation cost. DETAILED DESCRIPTION
[0023] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0024] The present application provides a method for preparing anhydrous lithium iodide, comprising the following steps: In a protective atmosphere and light-proof conditions, potassium iodide, an organic solvent and lithium tetrafluoroborate are mixed and reacted to obtain anhydrous lithium iodide crude product, which is then post-treated to obtain anhydrous lithium iodide.
[0025] Specifically, the organic solvent is an organic solvent that can dissolve potassium iodide, lithium tetrafluoroborate and lithium iodide, but does not dissolve potassium tetrafluoroborate. It can also be understood that potassium iodide, lithium tetrafluoroborate and lithium iodide have high solubility in the organic solvent, and potassium tetrafluoroborate has low solubility in the organic solvent.
[0026] The preparation method of anhydrous lithium iodide provided by the present application is to synthesize anhydrous lithium iodide by double decomposition reaction, which is specifically as follows: potassium iodide is added to an organic solvent, mixed evenly, and then lithium tetrafluoroborate is added for mixed reaction. The reaction principle is that potassium iodide and lithium tetrafluoroborate ions are exchanged with each other to generate lithium iodide and potassium tetrafluoroborate. The valence of the elements before and after the reaction remains unchanged. At the same time, because potassium tetrafluoroborate is insoluble in organic solvents, while lithium iodide, potassium iodide, and lithium tetrafluoroborate are all soluble in organic solvents, the concentration of potassium tetrafluoroborate in the solution is reduced, thereby promoting the reaction to proceed in the forward direction and the composite decomposition reaction to occur. The specific reaction equation is as follows: .
[0027] Compared with the existing method for preparing lithium iodide, the method for preparing anhydrous lithium iodide provided by the present application adopts double decomposition reaction to synthesize anhydrous lithium iodide. The double decomposition reaction avoids the appearance of crystal water in the generated lithium iodide product, so that vacuum and high temperature conditions do not need to be used during post-treatment, reducing the process difficulty; and avoiding high temperature conditions, which also prevents the product from being decomposed and oxidized by high temperature, thereby improving the purity of the product and improving the product yield; the double decomposition reaction is used to prepare anhydrous lithium iodide, and no crystal water is produced, and there is no need to remove the crystal water, thereby reducing the process of removing the crystal water and reducing the preparation cost.
[0028] In some embodiments, the organic solvent includes one or more of an ether organic solvent and an alcohol organic solvent.
[0029] Specifically, the organic solvent is selected from at least one of an ether organic solvent and an alcohol organic solvent, which can dissolve potassium iodide, lithium tetrafluoroborate and lithium iodide, and at the same time, is an organic solvent that does not dissolve potassium tetrafluoroborate. Potassium tetrafluoroborate generated after the reaction of potassium iodide and lithium tetrafluoroborate is insoluble in the organic solvent, which can reduce the concentration of potassium tetrafluoroborate in the organic solvent and promote the forward progress of the double decomposition reaction.
[0030] In some embodiments, the ether organic solvent includes one or more of ethylene glycol dimethyl ether, diethyl ether, 1,4-dioxane, and tetrahydrofuran; the alcohol organic solvent includes anhydrous ethanol, ethylene glycol, and the like.
[0031] In some preferred embodiments, the organic solvent is anhydrous ethanol.
[0032] The organic solvent is preferably anhydrous ethanol, which does not contain water. At the same time, potassium iodide, lithium tetrafluoroborate and lithium iodide have high solubility in the anhydrous ethanol solvent, and potassium tetrafluoroborate has low solubility in anhydrous ethanol. Potassium tetrafluoroborate precipitates are generated during the reaction, which promotes the double decomposition reaction and plays a role in effectively purifying the product.
[0033] In some embodiments, the mass of the organic solvent is m 1 The mass of the potassium iodide and the lithium tetrafluoroborate is m 2 , m 1 :m 2 It is (4~6):1.
[0034] Specifically, 1 and m 2 The ratio is in the range of (4~6):1, which is conducive to the effective dissolution of potassium iodide, lithium tetrafluoroborate and lithium iodide by organic solvents such as anhydrous ethanol. At room temperature, the solubility of potassium tetrafluoroborate in anhydrous ethanol is poor, and lithium iodide can be obtained by double decomposition reaction; at the same time, it can reduce the amount of anhydrous ethanol used and reduce the cost, and also increase the reaction concentration and accelerate the reaction rate.
[0035] If the amount of organic solvent used is too high, the reaction rate will be greatly reduced and it will take more than 12 hours to complete the reaction. If the amount of organic solvent used is too low, the raw materials potassium iodide, lithium tetrafluoroborate and lithium iodide cannot be fully dissolved.
[0036] The ratio of m1:m2 can be 4:1, 4.5:1, 5.0:1, 5.5:1, 6:1, etc. 1 and m 2 The ratio can be in the range of (4~6):1.
[0037] In some embodiments, the molar ratio of the potassium iodide to the lithium tetrafluoroborate is 1:1.
[0038] Specifically, the molar ratio range of potassium iodide and lithium tetrafluoroborate is limited to ensure that one of the raw materials is completely reacted, thereby reducing production costs.
[0039] In some embodiments, obtaining anhydrous lithium iodide by post-treatment comprises the following steps: Filtration, distillation and drying are performed in sequence to obtain anhydrous lithium iodide.
[0040] Specifically, potassium iodide, an organic solvent, and lithium tetrafluoroborate are mixed for reaction. First, precipitated potassium tetrafluoroborate is generated in the solution. As the reaction proceeds, the reaction ends when no precipitated potassium tetrafluoroborate is generated in the solution. After the reaction ends, the mixed solution is first filtered to remove the insoluble potassium tetrafluoroborate precipitate, and then distilled and dried to obtain anhydrous lithium iodide.
[0041] In some embodiments, the filtration comprises the following steps: filtering to obtain a supernatant liquid under the conditions of a protective atmosphere, avoiding light and a temperature t of -10°C to 10°C.
[0042] Specifically, after the reaction is completed, a mixed solution is obtained, and the mixed solution is filtered in a protective atmosphere, away from light and at a temperature within a range of -10°C to 10°C to remove insoluble potassium tetrafluoroborate precipitate, and the supernatant is collected.
[0043] During filtration, the filtration temperature is limited to the range of -10°C to 10°C. At a lower temperature, the solubility of potassium tetrafluoroborate in organic solvents such as anhydrous ethanol is lower, which is conducive to removing the insoluble potassium tetrafluoroborate. The specific temperature t can be in the range of -10~-5°C, -5~-2°C, -2~0°C, 0~3°C, 3~5°C, 5~8°C or 8~10°C.
[0044] In some preferred embodiments, the supernatant is obtained by filtering at a temperature in the range of -10°C≤t≤0°C.
[0045] The filtration is preferably carried out at a temperature within the range of -10°C ≤ t ≤ 0°C. The solubility of potassium tetrafluoroborate in organic solvents such as anhydrous ethanol is lower, which is conducive to removing more insoluble potassium tetrafluoroborate.
[0046] In some more preferred embodiments, the supernatant is obtained by filtering at 0°C.
[0047] Filtration is performed at 0°C and more insoluble potassium tetrafluoroborate can be removed under low process cost conditions.
[0048] In some embodiments, the distillation comprises the following steps: in a protective atmosphere and light-proof conditions, the supernatant is subjected to reduced pressure rotary evaporation to obtain a crude lithium iodide product.
[0049] Specifically, the organic solvent in the supernatant is removed by vacuum rotary evaporation to obtain crude lithium iodide.
[0050] In some embodiments, the distillation temperature of the vacuum rotary evaporation is 30-70° C.; The vacuum rotary evaporation temperature is in the range of 30-70°C, which is beneficial to remove the organic solvent in the supernatant and reduce the production cost. Specifically, the vacuum rotary evaporation temperature can be in the range of 30-40°C, 40-50°C, 50-60°C or 60-70°C, as long as the vacuum rotary evaporation temperature is in the range of 30-70°C.
[0051] In some preferred embodiments, the distillation temperature of the vacuum rotary evaporation is 40-60°C.
[0052] In some embodiments, drying comprises the following steps: drying the crude lithium iodide under a protective atmosphere and light-proof conditions to obtain the anhydrous lithium iodide.
[0053] Specifically, the crude lithium iodide is dried to remove the organic solvent and free iodine on the surface of the crude lithium iodide to obtain anhydrous lithium iodide.
[0054] Carrying out reactions, distillations, drying, etc. in a protective atmosphere and avoiding light conditions is to prevent lithium iodide from being exposed to air or from being oxidized, decomposed, or deteriorated under light conditions.
[0055] The protective atmosphere includes nitrogen and rare gases. The rare gases include helium, argon, etc.
[0056] In some embodiments, the drying temperature is 40-70° C., and the drying time is 3-4 hours.
[0057] Specifically, the drying temperature is between 40-70° C. Within this temperature range, the crude lithium iodide product can be completely dried, and the crude lithium iodide product can be prevented from deteriorating due to high temperature, thereby affecting the purity of the product.
[0058] In some preferred embodiments, the drying temperature is 55-60°C.
[0059] The drying temperature is preferably 55-60°C, which can not only reduce the cost, but also completely dry the crude lithium iodide and improve the product purity.
[0060] Potassium iodide, an organic solvent, and lithium tetrafluoroborate are mixed and reacted to generate potassium tetrafluoroborate solid and anhydrous lithium iodide. The reaction temperature is 0-30°C and the reaction time is 1-2h.
[0061] Specifically, within the temperature range of 0 to 30°C, the solubility of potassium tetrafluoroborate in organic solvents is relatively low, and the potassium tetrafluoroborate formed by ion exchange with potassium iodide and lithium tetrafluoroborate exists in the form of a precipitate, which is conducive to the double decomposition reaction to generate lithium iodide; the reaction time is 1 to 2 hours, the reaction time is short, and the process time is short.
[0062] The present invention is further described below by way of examples.
[0063] Example 1 This example is used to illustrate a method for preparing anhydrous lithium iodide disclosed in the present invention.
[0064] S1: Add 166 g (1 mol) of potassium iodide to a brown three-necked bottle, add 1300 g of anhydrous ethanol as an organic solvent under nitrogen atmosphere, and then add 93.75 g (1 mol) of lithium tetrafluoroborate to mix, and react at room temperature of 25°C ± 5°C for 1 hour. Stop the reaction when no precipitation is produced; m 1 :m 2 It is 5:1.
[0065] S2: After the reaction is completed, a mixed liquid is obtained, and the mixed liquid is filtered to remove the insoluble potassium tetrafluoroborate precipitate to obtain a supernatant; the filtering conditions are nitrogen, light-proof, and 0°C ice water bath.
[0066] S3: Under the condition of nitrogen and light protection, the supernatant was subjected to vacuum rotary evaporation, and the vacuum rotary evaporation temperature was controlled at 40°C to obtain a white crude lithium iodide product.
[0067] S4: Dry the crude white lithium iodide product under nitrogen and light-proof conditions at a drying temperature of 60° C. for 3 hours to remove the organic solvent anhydrous ethanol and free iodine on the surface of the crude white lithium iodide product to obtain anhydrous lithium iodide product.
[0068] Example 2 The steps of this embodiment are the same as those of embodiment 1, except that in step S2, the filtration temperature is -8°C, and the rest are the same as those of embodiment 1.
[0069] Example 3 The steps of this embodiment are the same as those of embodiment 1, except that in step S2, the filtration temperature is 10°C, and the rest are the same as those of embodiment 1.
[0070] Example 4 The steps of this embodiment are the same as those of embodiment 1, except that in step S2, the filtration temperature is 15°C, and the rest are the same as those of embodiment 1.
[0071] Example 5 The steps of this embodiment are similar to those of embodiment 1, except that in step S1, the amount of anhydrous ethanol added as organic solvent is 1560 g, m 1 :m 2 It is 6:1.
[0072] Example 6 The steps of this embodiment are similar to those of embodiment 1, except that in step S1, the amount of anhydrous ethanol added as organic solvent is 1040 g, m 1 :m 2 It is 4:1.
[0073] Example 7 The steps of this embodiment are similar to those of embodiment 1, except that in step S1, the amount of anhydrous ethanol added as organic solvent is 1820 g, m 1 :m 2 is 7:1; reaction time is 2h.
[0074] Example 8 The steps of this embodiment are similar to those of embodiment 1, except that in step S1, the amount of anhydrous ethanol added as organic solvent is 780 g, m 1 :m 2 It is 3:1.
[0075] Example 9 The steps of this embodiment are similar to those of embodiment 1, except that in step S4, the drying temperature is 55°C.
[0076] Example 10 The steps of this embodiment are similar to those of embodiment 1, except that in step S4, the drying temperature is 40°C.
[0077] Embodiment 11 The steps of this embodiment are similar to those of embodiment 1, except that in step S4, the drying temperature is 70°C.
[0078] Example 12 The steps of this embodiment are similar to those of embodiment 1, except that in step S4, the drying temperature is 80°C.
[0079] Embodiment 13 The steps of this embodiment are similar to those of embodiment 1, except that in step S4, the drying temperature is 30°C.
[0080] Embodiment 14 The steps of this embodiment are similar to those of embodiment 1, except that in step S1, the reaction temperature of the mixture of potassium iodide, anhydrous ethanol and lithium tetrafluoroborate is 50°C.
[0081] Embodiment 15 The steps of this embodiment are similar to those of embodiment 1, except that in step S1, the molar ratio of potassium iodide to the lithium tetrafluoroborate is 1:1.2.
[0082] Example 16 The steps of this embodiment are similar to those of embodiment 1, except that in step S1, the molar ratio of potassium iodide to the lithium tetrafluoroborate is 1:0.8.
[0083] Embodiment 17 The steps of this embodiment are similar to those of embodiment 1, except that in step S1, the reaction temperature of the mixture of potassium iodide, anhydrous ethanol and lithium tetrafluoroborate is 10°C.
[0084] Comparative Example 1 Ammonium iodide and metallic lithium are reacted in liquid ammonia to prepare lithium iodide to obtain a crystalline hydrate of lithium iodide. The crystalline hydrate is heated in a vacuum for dehydration and sublimation to obtain anhydrous lithium iodide.
[0085] The yield and purity of the anhydrous lithium iodide products prepared in the above examples and comparative examples are recorded in Table 1.
[0086] Table 1 It can be seen from Table 1 that, by comparing Example 1 with Comparative Example 1, the anhydrous lithium iodide preparation method provided in the present application adopts double decomposition reaction to synthesize anhydrous lithium iodide. The double decomposition reaction avoids the appearance of crystal water in the generated lithium iodide product, and has high yield and high purity. At the same time, since no crystal water is generated, high temperature conditions are avoided, and there is no need to remove crystal water, thereby reducing the preparation cost. Comparing Example 1-3 with Example 4, in step S2 of Example 4, the filtration temperature is greater than -10~10°C. It is speculated that the filtration temperature is high, and the solubility of the generated potassium tetrafluoroborate in the organic solvent anhydrous ethanol is high. The purity of the generated anhydrous lithium iodide product is low, and the yield is reduced. Comparing Example 1, 5-6 with Example 7-8, the m added in step S1 1 :m 2The value is lower than 4:1, and the organic solvent content is too low, which affects the full dissolution of potassium iodide, lithium tetrafluoroborate and lithium iodide, and the yield and purity of anhydrous lithium iodide products are reduced; 1 :m 2 The value is higher than 6:1, too much organic solvent is added, the reaction rate is greatly reduced, and the yield of the anhydrous lithium iodide product is lower; This indicates that in step S1, m 1 :m 2 When the value of is in the range of (4~6):1, the generated anhydrous lithium iodide product has high purity and high yield.
[0087] Comparing Examples 1, 9-11 with Examples 12-13, the drying temperature for drying the crude white lithium iodide product is in the range of 40-70°C, and the generated anhydrous lithium iodide product has a high yield and a higher purity.
[0088] In comparison between Examples 1 and 17 and Example 14, the reaction temperature of the mixed reaction of potassium iodide, anhydrous ethanol and lithium tetrafluoroborate is in the range of 0 to 30° C. The solubility of potassium tetrafluoroborate in the organic solvent anhydrous ethanol is low, which promotes the reaction and the yield of the generated anhydrous lithium iodide is higher.
[0089] Comparison between Example 1 and Examples 15 and 16 shows that the molar ratio of potassium iodide to the lithium tetrafluoroborate is 1:1, and the generated anhydrous lithium iodide has high purity and high yield.
[0090] 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing anhydrous lithium iodide, characterized in that: The following steps are involved: In a protective atmosphere and light-proof conditions, potassium iodide, an organic solvent and lithium tetrafluoroborate are mixed and reacted to obtain anhydrous lithium iodide crude product, which is then post-treated to obtain anhydrous lithium iodide.
2. The method for preparing anhydrous lithium iodide according to claim 1, characterized in that: The organic solvent includes one or more of an ether organic solvent and an alcohol organic solvent.
3. The method for preparing anhydrous lithium iodide according to claim 2, characterized in that: The ether organic solvent includes one or more of ethylene glycol dimethyl ether, ethyl ether, 1,4-dioxane, and tetrahydrofuran; the alcohol organic solvent includes one or more of anhydrous ethanol and ethylene glycol; Preferably, the organic solvent is anhydrous ethanol.
4. The method for preparing anhydrous lithium iodide according to claim 1, characterized in that: The mass of the organic solvent is m1, the mass of the potassium iodide and the lithium tetrafluoroborate is m2, and m1:m2 is (4-6):
1.
5. The method for preparing anhydrous lithium iodide according to claim 1, characterized in that: The molar ratio of the potassium iodide to the lithium tetrafluoroborate is 1:
1.
6. The method for preparing anhydrous lithium iodide according to claim 1, characterized in that: Obtaining anhydrous lithium iodide through post-treatment comprises the following steps: Filtration, distillation and drying are performed in sequence to obtain anhydrous lithium iodide.
7. The method for preparing anhydrous lithium iodide according to claim 6, characterized in that: The filtration comprises the following steps: filtering to obtain a supernatant liquid under the conditions of a protective atmosphere, avoiding light and a temperature t of -10°C to 10°C.
8. The method for preparing anhydrous lithium iodide according to claim 7, characterized in that: The distillation comprises the following steps: in a protective atmosphere and light-proof conditions, subjecting the supernatant to vacuum rotary evaporation to obtain a crude lithium iodide product; The drying comprises the following steps: drying the crude lithium iodide under a protective atmosphere and light-proof conditions to obtain the anhydrous lithium iodide.
9. The method for preparing anhydrous lithium iodide according to claim 8, characterized in that: The temperature of the vacuum rotary evaporation is 40-60°C; The drying temperature is 40~70℃ and the drying time is 3~4h.
10. The method for preparing anhydrous lithium iodide according to claim 1, characterized in that: Potassium iodide, an organic solvent, and lithium tetrafluoroborate are mixed and reacted to generate potassium tetrafluoroborate solid and anhydrous lithium iodide. The reaction temperature is 0-30°C and the reaction time is 1-2h.