阅读说明：本技术 硒化锂的制备方法 (Preparation method of lithium selenide ) 是由 潘禹君 伽龙 杨莹 严超 于 2021-06-11 设计创作，主要内容包括：本发明提供一种硒化锂的制备方法,属于锂电池技术领域,包括以下步骤：在惰性气氛下配制含锂还原性溶液；配制含硒溶液；在惰性气氛下,将含硒溶液和含锂还原性溶液混合,室温下搅拌反应4-6h得到反应物料；反应结束后取反应物料中的不溶物即得到硒化锂。本发明以含硒溶液与含锂还原性溶液为原料,在常温常压下进行反应,制备方法安全,且生产成本低、反应过程无有害副产物,得到的硒化锂粉体晶相完整。(The invention provides a preparation method of lithium selenide, belonging to the technical field of lithium batteries and comprising the following steps: preparing a lithium-containing reducing solution under an inert atmosphere; preparing a selenium-containing solution; mixing the selenium-containing solution and the lithium-containing reducing solution under inert atmosphere, and stirring and reacting for 4-6h at room temperature to obtain a reaction material; and after the reaction is finished, taking insoluble substances in the reaction materials to obtain the lithium selenide. The invention takes the selenium-containing solution and the lithium-containing reducing solution as raw materials, and the reaction is carried out at normal temperature and normal pressure, the preparation method is safe, the production cost is low, no harmful by-products are generated in the reaction process, and the obtained lithium selenide powder has complete crystal phase.)

1. The preparation method of the lithium selenide is characterized by comprising the following steps:

preparing a lithium-containing reducing solution under an inert atmosphere;

preparing a selenium-containing solution;

mixing the selenium-containing solution and the lithium-containing reducing solution under inert atmosphere, and stirring and reacting for 4-6h at room temperature to obtain a reaction material;

and after the reaction is finished, taking insoluble substances in the reaction materials to obtain the lithium selenide.

2. The method for preparing lithium selenide according to claim 1, wherein the concentration of the lithium-containing reducing solution is 0.1 to 10 mol/L.

3. The method for preparing lithium selenide according to claim 2, wherein the concentration of the lithium-containing reducing solution is 0.2 to 5 mol/L.

4. The method for preparing lithium selenide according to claim 1, wherein the molar ratio of lithium in the lithium-containing reducing solution to selenium in the selenium-containing solution is 1: 0.3-0.5.

5. The method for preparing lithium selenide according to claim 1, wherein the preparation of the lithium-containing reducing solution comprises:

dissolving aromatic hydrocarbon in an organic ether solvent to obtain an organic solution after complete dissolution;

and adding metal lithium into the organic solution, and obtaining a lithium-containing reducing solution after complete dissolution.

6. The method for preparing lithium selenide according to claim 5, wherein the organic ether solvent is selected from one or more of monoethers, mixed ethers and cyclic ethers, and the water content in the organic ether solvent is less than 50 ppm.

7. The method of claim 5, wherein the aromatic hydrocarbon is one or more selected from the group consisting of monocyclic aromatic hydrocarbon, polycyclic aromatic hydrocarbon, polybenzoate hydrocarbon, and non-benzene aromatic hydrocarbon.

8. The method for preparing lithium selenide according to claim 1, wherein the lithium-containing reducing solution is an n-butyllithium solution.

9. The method for preparing lithium selenide according to claim 1, wherein the preparation of the selenium-containing solution comprises:

selenium powder with the water content of less than 0.1ppm is dissolved in organic ether, aliphatic hydrocarbon and cyanogen solvents, and selenium-containing solution is obtained after complete dissolution.

10. The preparation method of lithium selenide according to claim 1, wherein the reaction material is filtered or centrifuged to obtain insoluble substances, and the insoluble substances are washed and dried at 40-75 ℃ for 24-48h in an inert atmosphere to obtain lithium selenide powder.

Technical Field

The invention belongs to the field of lithium batteries, and particularly relates to a preparation method of lithium selenide.

Background

The widespread use of secondary batteries in various aspects places higher demands on the energy density of batteries, and currently, lithium-sulfur batteries are used because of their higher theoretical specific energy (2600Wh kg)^-1) The lithium sulfur battery is widely researched, but the shuttle and the electric conductivity of polysulfide still exist in the current lithium sulfur batteryAnd the like.

Selenium has more excellent conductivity as a chalcogen of sulfur than sulfur, and further, a lithium selenium battery has a similar volumetric energy density to a lithium sulfur battery, which makes selenium have a high research significance in the battery field, among which lithium selenide (Li)₂Se) is a commonly used electrode material in lithium selenium batteries, but lithium selenide has the disadvantage of being susceptible to oxidation and therefore needs to be stored in an inert atmosphere.

The existing methods for synthesizing lithium selenide are few, and mainly comprise the following steps:

the first type is that selenium powder and lithium triethylborohydride are used as raw materials, the raw materials are dissolved in tetrahydrofuran solution to react, and insoluble substances obtained by filtering are lithium selenide, but the lithium triethylborohydride is expensive and has no economy.

And the second type is that selenium powder and lithium powder are used as raw materials, liquid ammonia is used as a solvent for reaction, and insoluble substances obtained by filtering are lithium selenide.

And the third type is that selenium powder and lithium hydride are used as raw materials to be ball-milled in an inert atmosphere to obtain lithium selenide powder, wherein the lithium hydride in the method has poor safety and high cost in the ball-milling process.

Disclosure of Invention

Based on the background problems, the invention aims to provide a preparation method of lithium selenide, which takes a selenium-containing solution and a lithium-containing reducing solution as raw materials to react at normal temperature and normal pressure, and has the advantages of safe preparation method, low production cost and no harmful by-products in the reaction process.

In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:

the preparation method of the lithium selenide comprises the following steps:

preparing a lithium-containing reducing solution under an inert atmosphere;

preparing a selenium-containing solution;

mixing the selenium-containing solution and the lithium-containing reducing solution under inert atmosphere, and stirring and reacting for 4-6h at room temperature to obtain a reaction material;

and after the reaction is finished, taking insoluble substances in the reaction materials to obtain the lithium selenide.

Further, the concentration of the lithium-containing reducing solution is 0.1-10 mol/L.

Further, the concentration of the lithium-containing reducing solution is 0.2-5 mol/L.

Further, the molar ratio of lithium in the lithium-containing reducing solution to selenium in the selenium-containing solution is 1: 0.3-0.5.

In one embodiment, the preparation of the lithium-containing reducing solution comprises:

dissolving aromatic hydrocarbon in an organic ether solvent to obtain an organic solution after complete dissolution;

and adding metal lithium into the organic solution, and obtaining a lithium-containing reducing solution after complete dissolution.

Further, the organic ether solvent is selected from one or more of monoether, mixed ether and cyclic ether, and the water content in the organic ether solvent is less than 50 ppm.

Further, the aromatic hydrocarbon is selected from one or more of monocyclic aromatic hydrocarbon, polycyclic aromatic hydrocarbon, polyphenyl aliphatic hydrocarbon and non-benzene aromatic hydrocarbon.

In one embodiment, the lithium-containing reducing solution is an n-butyllithium solution.

Further, the preparation of the selenium-containing solution comprises:

selenium powder with the water content of less than 0.1ppm is dissolved in organic ether, aliphatic hydrocarbon and cyanogen solvents, and selenium-containing solution is obtained after complete dissolution.

Further, filtering or centrifuging the reaction materials to obtain insoluble substances, washing the insoluble substances, and drying at 40-75 ℃ for 24-48h in an inert atmosphere to obtain the lithium selenide powder.

Compared with the prior art, the invention has the following effects:

1. the invention takes the selenium-containing solution and the lithium-containing reducing solution as raw materials, and the reaction is carried out at normal temperature and normal pressure, the preparation method is safe, the production cost is low, no harmful by-products are generated in the reaction process, and the obtained lithium selenide powder has complete crystal phase.

2. According to the invention, aromatic hydrocarbon is added when the lithium-containing reducing solution is prepared, the aromatic hydrocarbon such as naphthalene, biphenyl and the like can react with lithium to generate lithium naphthalene and lithium biphenyl with reducing property, and then the lithium naphthalene or the lithium biphenyl can react with selenium powder to generate lithium selenide and naphthalene; the lithium-containing reducing solution may be a lithium-containing solution having reducing properties itself, such as n-butyllithium, as it is.

3. According to the invention, the insoluble substance obtained by filtering or centrifuging the reaction material is lithium selenide, and the obtained supernatant can be recycled, so that the method has the advantages of simplicity, economy, environmental friendliness and suitability for industrial production.

Drawings

FIG. 1 is an XRD pattern of lithium selenide powder prepared in example 2 of the present invention;

FIG. 2 is an SEM image of lithium selenide powder prepared in example 2 of the invention.

Detailed Description

In order to solve the defects of poor safety, high cost and the like of the existing lithium selenide preparation method, the invention provides the lithium selenide preparation method, which takes a selenium-containing solution and a lithium-containing reducing solution as raw materials to react at normal temperature and normal pressure, the preparation method is safe, the production cost is low, no harmful by-products are generated in the reaction process, and the obtained lithium selenide powder has complete crystal phase.

The invention will be elucidated by means of specific embodiments.

The water content in the organic ether solvent used in the following examples was <50ppm, and the water content in the selenium powder was <0.1 ppm.

Example 1

The preparation method of the lithium selenide comprises the following steps:

(1) weighing 0.3204g (0.0025mol) of naphthalene, dissolving in 5ml of anhydrous tetrahydrofuran to obtain an organic solution after complete dissolution, weighing 0.0174g (0.0025mol) of metal lithium foil under an inert atmosphere, adding the metal lithium foil into the organic solution, and obtaining 0.5mol/L of lithium-containing reducing solution (lithium naphthalene solution) after complete dissolution;

(2) weighing 0.0987g (0.00125mol) of selenium powder, dissolving in a tetrahydrofuran solvent, and stirring at room temperature for 2 hours to obtain a selenium-containing solution;

(3) mixing the lithium naphthalene solution in the step (1) and the selenium-containing solution in the step (2) under an inert atmosphere, stirring and reacting for 4 hours at room temperature, and obtaining a reaction material after the reaction is finished;

(4) and (3) centrifuging the reaction material in the step (3) to obtain an insoluble substance and a supernatant, wherein the centrifugation speed is 8000r/min, the centrifugation time is 20min, washing and centrifuging the obtained insoluble substance for 3 times by using anhydrous tetrahydrofuran, the centrifugation speed is 5000r/min, the centrifugation time is 10min, then drying for 48h at 40 ℃ in an inert atmosphere to obtain lithium selenide powder, and recycling the obtained supernatant for preparing the lithium naphthalene solution.

Example 2

The preparation method of the lithium selenide comprises the following steps:

(1) weighing 0.6408g (0.005mol) of naphthalene, dissolving in 5ml of anhydrous ethylene glycol dimethyl ether to obtain an organic solution after complete dissolution, weighing 0.0347g (0.005mol) of metal lithium foil in an inert atmosphere, adding the metal lithium foil into the organic solution, and obtaining 1mol/L of lithium-containing reducing solution (lithium naphthalene solution) after complete dissolution;

(2) weighing 0.1974(0.0025mol) selenium powder, dissolving in anhydrous glycol dimethyl ether solvent, and stirring at room temperature for 2h to obtain selenium-containing solution;

(3) mixing the lithium naphthalene solution in the step (1) and the selenium-containing solution in the step (2) under an inert atmosphere, stirring and reacting for 4 hours at room temperature, and obtaining a reaction material after the reaction is finished;

(4) and (3) centrifuging the reaction material in the step (3) to obtain an insoluble substance and a supernatant, wherein the centrifugation speed is 8000r/min, the centrifugation time is 20min, washing and centrifuging the obtained insoluble substance for 3 times by using anhydrous glycol dimethyl ether, the centrifugation speed is 5000r/min, the centrifugation time is 10min, drying is carried out for 24h at 75 ℃ in an inert atmosphere, and then lithium selenide powder can be obtained, and the obtained supernatant is recycled for preparing a lithium naphthalene solution.

Fig. 1 shows XRD diffraction pattern of lithium selenide prepared in this example, and it can be seen from fig. 1 that lithium selenide powder corresponding to PDF card (23-0072) can be synthesized by the present method; fig. 2 is an SEM image of lithium selenide prepared in this example, and it can be seen from fig. 2 that the method can be used to synthesize nanospheres with aggregated nanoparticles.

Example 3

The preparation method of lithium selenide is different from the embodiment 2 in that in the embodiment, in the step (3), the lithium naphthalene solution in the step (1) and the selenium-containing solution in the step (2) are mixed, stirred and reacted for 5 hours at room temperature, a reaction material is obtained after the reaction is finished, and the rest steps are the same as the embodiment 2.

Example 4

The preparation method of lithium selenide is different from the embodiment 2 in that in the embodiment, in the step (3), the lithium naphthalene solution in the step (1) and the selenium-containing solution in the step (2) are mixed, stirred and reacted for 6 hours at room temperature, a reaction material is obtained after the reaction is finished, and the rest steps are the same as the embodiment 2.

Example 5

The preparation method of lithium selenide is different from example 2 in that in step (1), the concentration of the prepared lithium-containing reducing solution (lithium naphthalene solution) is 5mol/L, specifically, 3.204g (0.025mol) of naphthalene is weighed and dissolved in 5ml of diethyl ether, an organic solution is obtained after complete dissolution, 0.1735g (0.025mol) of metal lithium foil is weighed and added into the organic solution under an inert atmosphere, and a 5mol/L lithium-containing reducing solution (lithium naphthalene solution) is obtained after complete dissolution.

Example 6

The preparation method of lithium selenide is different from example 2 in that in step (1), the concentration of the prepared lithium-containing reducing solution (lithium naphthalene solution) is 0.2mol/L, specifically, 0.12816g (0.001mol) of naphthalene is weighed and dissolved in 5ml of ethylene oxide to obtain an organic solution after complete dissolution, 0.00694g (0.001mol) of metal lithium foil is weighed and added into the organic solution under an inert atmosphere to obtain 0.2mol/L of lithium-containing reducing solution (lithium naphthalene solution) after complete dissolution.

Example 7

The preparation method of lithium selenide is different from the embodiment 2 in that in the embodiment, in the step (2), 0.1180g (0.0015mol) of selenium powder is weighed and dissolved in an anhydrous glycol dimethyl ether solvent, and the solution containing selenium is obtained after stirring for 2 hours at room temperature;

example 8

The preparation method of lithium selenide is different from the embodiment 2 in that biphenyl is selected to be dissolved in 5ml of anhydrous ethylene glycol dimethyl ether to form an organic solution in the step (1), and other steps are consistent with the embodiment 2.

Example 9

The preparation method of the lithium selenide comprises the following steps:

(1) measuring 5ml of 10mol/L n-butyllithium solution;

(2) weighing 1.974g of selenium powder (0.025mol) and dissolving in an n-hexane solvent, and stirring at room temperature for 2h to obtain a selenium-containing solution;

(3) mixing the n-butyllithium solution obtained in the step (1) and the selenium-containing solution obtained in the step (2) under an inert atmosphere, stirring and reacting for 4 hours at room temperature, and obtaining a reaction material after the reaction is finished;

(4) and (4) centrifuging the reaction material obtained in the step (3) to obtain an insoluble substance and a supernatant, wherein the centrifugation speed is 8000r/min, the centrifugation time is 20min, washing and centrifuging the obtained insoluble substance for 3 times by using normal hexane, the centrifugation speed is 5000r/min, the centrifugation time is 10min, and then drying in an inert atmosphere to obtain the lithium selenide powder.

Example 10

The preparation method of the lithium selenide comprises the following steps:

(1) weighing 0.0669g (0.0005mol) of lithium iodide, dissolving in 5ml of anhydrous acetonitrile solvent, and completely dissolving to obtain a lithium-containing reducing solution with the concentration of 0.1 mol/L;

(2) weighing 0.0197g of selenium powder (0.00025mol) and dissolving in an anhydrous acetonitrile solvent, and stirring at room temperature for 2h to obtain a selenium-containing solution;

(3) mixing the lithium-containing reducing solution obtained in the step (1) and the selenium-containing solution obtained in the step (2) in an inert atmosphere, stirring and reacting for 4 hours at room temperature, and obtaining a reaction material after the reaction is finished;

(4) and (4) centrifuging the reaction material obtained in the step (3) to obtain an insoluble substance and a supernatant, wherein the centrifugation speed is 8000r/min, the centrifugation time is 20min, washing and centrifuging the obtained insoluble substance for 3 times by using anhydrous acetonitrile, the centrifugation speed is 5000r/min, the centrifugation time is 10min, and then drying in an inert atmosphere to obtain the lithium selenide powder.

Comparative example

The preparation method of the lithium selenide comprises the following steps:

(1) weighing 0.0347g (0.005mol) of metal lithium foil in an inert atmosphere, dissolving the metal lithium foil in 5ml of anhydrous ethylene glycol dimethyl ether, and obtaining 1mol/L lithium-containing solution after complete dissolution;

(2) weighing 0.1974(0.0025mol) selenium powder, dissolving in anhydrous glycol dimethyl ether solvent, and stirring at room temperature for 2h to obtain selenium-containing solution;

(3) mixing the lithium-containing solution obtained in the step (1) and the selenium-containing solution obtained in the step (2) in an inert atmosphere, stirring and reacting for 4 hours at room temperature, and obtaining a reaction material after the reaction is finished;

(4) and (3) centrifuging the reaction material in the step (3), wherein the centrifugal rotating speed is 8000r/min, the centrifugal time is 20min, and insoluble substances are not obtained after the centrifugation is finished, so that the method for the comparative example can not generate lithium selenide, and the fact that the lithium-containing solution has reducibility is proved, and lithium selenide can be prepared only when the lithium-containing solution reacts with selenium.

It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications belong to the protection scope of the present invention.