阅读说明：本技术 一种高纯硫化锂的制备方法及应用 (Preparation method and application of high-purity lithium sulfide ) 是由 刘延成 于 2021-06-23 设计创作，主要内容包括：本发明公开了一种高纯硫化锂的制备方法及应用,本发明利用氨基锂残次品与硫化氢进行反应制备硫化锂。由于氨基锂及其副产物与金属锂相比,更容易与硫化氢反应,利用氨基锂残次品与硫化氢反应,一方面加快了金属锂与硫化氢反应的进度,另一方面反应参与的少量锂氮化合物本身具有较高电子电导率,由此制备的硫化锂用作硫化物电解质能够达到增强其电子电导率的性能。而且对于氨基锂残次品的回收利用,也极大提高了经济效益。(The invention discloses a preparation method and application of high-purity lithium sulfide. The lithium amide and the by-products thereof are easier to react with hydrogen sulfide compared with the lithium metal, and the lithium amide defective products are used for reacting with the hydrogen sulfide, so that the reaction progress of the lithium metal and the hydrogen sulfide is accelerated, and a small amount of lithium nitrogen compounds involved in the reaction have high electronic conductivity, so that the prepared lithium sulfide can achieve the performance of enhancing the electronic conductivity when used as a sulfide electrolyte. But also greatly improves the economic benefit for recycling the lithium amide defective products.)

1. The preparation method of the high-purity lithium sulfide is characterized by comprising the following steps of:

performing ball milling on the lithium amide defective products until D50 is kept below 50 microns to obtain lithium amide particle powder;

placing the lithium amide particle powder in a reaction furnace with a stirring device, vacuumizing the reaction furnace until the vacuum degree is-0.1 mpa, raising the temperature of the reaction furnace to 200-300 ℃, introducing hydrogen sulfide gas into the reaction furnace to keep the pressure of the reaction furnace at 0.1-0.15mpa, and stirring for reacting for 3-5 hours;

closing hydrogen sulfide gas, raising the temperature of the reaction furnace to 400-430 ℃, preserving heat for 0.5-1 hour, and vacuumizing the reaction furnace to-0.1 mpa after heat preservation;

introducing hydrogen sulfide gas again to keep the pressure of the reaction furnace at 0.05-0.1mpa, and heating to 400-430 ℃ for reaction for 3-5 hours;

and performing ball milling, crushing and sieving on the reacted lithium sulfide, and controlling the D50 to be 10-50 microns.

2. The method for preparing high-purity lithium sulfide as claimed in claim 1, wherein the step of ball-milling the lithium amide inferiority comprises the following steps:

putting the lithium amide defective product into a zirconia ball milling tank, and carrying out ball milling for 8-10 hours at the rotating speed of 500-.

3. The method for preparing high-purity lithium sulfide as claimed in claim 1, wherein the lithium amide waste product contains more than 80% of lithium amide.

4. Use of a high purity lithium sulfide prepared by the process of claims 1-3 in an electrolyte.

Technical Field

The invention relates to the technical field of batteries, in particular to a preparation method and application of high-purity lithium sulfide.

Background

Lithium sulfide is used as the most important component of a solid sulfide lithium ion battery with high energy and high safety performance, is also used as a preparation raw material of a solid sulfide electrolyte and a positive electrode material of a high-capacity lithium sulfur battery, and the development, optimization and commercial application of the production process of the lithium sulfide are increasingly and generally concerned and valued. The lithium amide is mainly used for synthesis and is mainly applied to organic synthesis and pharmaceutical manufacturing, and the lithium amide is prepared by reacting metal lithium and ammonia gas at high temperature in industry, but impurities such as lithium hydride, lithium imide, lithium nitride and the like are easily generated in the production process, so that the purity of the lithium amide is not high, and defective products are generated (the main content is 80-95%).

The traditional method for preparing lithium sulfide mainly comprises three steps of 1, reducing lithium sulfate by carbon under the high-temperature condition; 2. reacting lithium hydroxide with hydrogen sulfide in NMP; 3. the lithium metal reacts with the sulfur. In the method 1, the solid reacts with the solid, the interface action is large, the reaction can only be carried out on the surface of the solid, the product purity is low, a large amount of impurities are contained, and the NMP in the method 2 is easy to deteriorate under the alkaline condition and difficult to recycle. The reaction conditions are harsh, the lithium sulfide is easy to deteriorate in the production of water, the purification is difficult, and in the method 3, the lithium and sulfur react violently and are easy to explode, the control is not easy, and polysulfide is easy to generate.

Disclosure of Invention

The invention mainly solves the technical problem of providing a preparation method and application of high-purity lithium sulfide, which can recover lithium amide defective products and prepare high-purity lithium sulfide at the same time.

In view of this, an embodiment of the present invention provides a method for preparing high-purity lithium sulfide, where the method includes the following steps: performing ball milling on the lithium amide defective products until D50 is kept below 50 microns to obtain lithium amide particle powder; placing the lithium amide particle powder in a reaction furnace with a stirring device, vacuumizing the reaction furnace until the vacuum degree is-0.1 mpa, raising the temperature of the reaction furnace to 200-300 ℃, introducing hydrogen sulfide gas into the reaction furnace to keep the pressure of the reaction furnace at 0.1-0.15mpa, and stirring for reacting for 3-5 hours; closing hydrogen sulfide gas, raising the temperature of the reaction furnace to 400-430 ℃, preserving heat for 0.5-1 hour, and vacuumizing the reaction furnace to-0.1 mpa after heat preservation; introducing hydrogen sulfide gas again to keep the pressure of the reaction furnace at 0.05-0.1mpa, and heating to 400-430 ℃ for reaction for 3-5 hours; and performing ball milling, crushing and sieving on the reacted lithium sulfide, and controlling the D50 to be 10-50 microns.

Wherein the ball milling of the lithium amide defective products comprises the following steps: putting the lithium amide defective product into a zirconia ball milling tank, and carrying out ball milling for 8-10 hours at the rotating speed of 500-.

Wherein the main content of the lithium amide in the lithium amide defective products is more than 80 percent.

In order to solve the above technical problems, the present invention provides another technical solution: provides the application of the high-purity lithium sulfide prepared by the preparation method in the electrolyte.

The invention has the beneficial effects that: different from the situation of the prior art, the lithium sulfide is prepared by reacting lithium amide defective products with hydrogen sulfide. The lithium amide and the by-products thereof are easier to react with hydrogen sulfide compared with the lithium metal, and the lithium amide defective products are used for reacting with the hydrogen sulfide, so that the reaction progress of the lithium metal and the hydrogen sulfide is accelerated, and a small amount of lithium nitrogen compounds involved in the reaction have high electronic conductivity, so that the prepared lithium sulfide can achieve the performance of enhancing the electronic conductivity when used as a sulfide electrolyte. But also greatly improves the economic benefit for recycling the lithium amide defective products.

Drawings

Fig. 1 is an XRD pattern of the prepared high purity lithium sulfide (PI film protection test).

Detailed Description

The technical solutions of the present invention will be described in detail below with reference to specific embodiments, but the following are only specific implementations of the present invention and are not intended to limit the scope of the present invention.

The invention provides a preparation method of high-purity lithium sulfide, which comprises the following steps:

the method comprises the following steps: performing ball milling on the lithium amide defective products until D50 is kept below 50 microns to obtain lithium amide particle powder;

step two: placing lithium amide particle powder in a reaction furnace with a stirring device, vacuumizing the reaction furnace until the vacuum degree is-0.1 mpa, raising the temperature of the reaction furnace to 200-300 ℃, introducing hydrogen sulfide gas into the reaction furnace to keep the pressure of the reaction furnace at 0.1-0.15mpa, and stirring for reacting for 3-5 hours;

step three: closing hydrogen sulfide gas, raising the temperature of the reaction furnace to 400-430 ℃, preserving the heat for 0.5-1 hour, and vacuumizing the reaction furnace to-0.1 mpa after the heat preservation is finished;

step four: introducing hydrogen sulfide gas again to keep the pressure of the reaction furnace at 0.05-0.1mpa, and heating to 400-430 ℃ for reaction for 3-5 hours;

step five: and performing ball milling, crushing and sieving on the reacted lithium sulfide, and controlling the D50 to be 10-50 microns.

Wherein D50 is the particle size corresponding to the cumulative percentage of particle size distribution of a sample at 50%.

In the first step, the ball milling of the lithium amide defective products specifically comprises the following steps: and (3) putting the lithium amide defective product into a zirconia ball milling tank, and carrying out ball milling for 8-10 hours at the rotating speed of 500-.

Wherein, the lithium amide defective product used in the invention has a main content of lithium amide of more than 80%.

The lithium sulfide is prepared by reacting the lithium amide defective products with hydrogen sulfide at high temperature. The method is mainly characterized in that lithium amide and byproducts thereof are easy to react with hydrogen sulfide compared with metal lithium (activation energy required by reaction is reduced by producing an intermediate product, and reducibility and alkalinity are increased), so that the lithium amide and byproducts thereof can react with hydrogen sulfide easily, the reaction progress of the metal lithium and the hydrogen sulfide is accelerated by utilizing the reaction of lithium amide defective products and the hydrogen sulfide, and a small amount of residual lithium nitrogen compounds (< 0.1%) in the reaction have high ionic conductivity, so that the prepared lithium sulfide can be synthesized into sulfide electrolyte to enhance the ionic conductivity. And the preparation method also recycles the lithium amide defective products, thereby greatly improving the economic benefit. Based on the preparation method, the purity of the prepared lithium sulfide is high and can reach more than 99.9%.

The process of the invention is described below with reference to several specific examples:

example 1

The method comprises the following steps: performing ball milling on the lithium amide defective products until D50 is kept below 50 microns to obtain lithium amide particle powder;

step two: placing lithium amide particle powder in a reaction furnace with a stirring device, vacuumizing the reaction furnace until the vacuum degree is-0.1 mpa, raising the temperature of the reaction furnace to 200 ℃, introducing hydrogen sulfide gas into the reaction furnace to keep the pressure of the reaction furnace at 0.1mpa, and stirring for reacting for 5 hours;

step three: closing hydrogen sulfide gas, raising the temperature of the reaction furnace to 430 ℃, preserving the heat for 0.5 hour, and vacuumizing the reaction furnace to-0.1 mpa after the heat preservation is finished;

step four: introducing hydrogen sulfide gas again to keep the pressure of the reaction furnace at 0.1mpa, and heating to 430 ℃ for reaction for 3 hours;

step five: and performing ball milling, crushing and sieving on the reacted lithium sulfide, and controlling the D50 to be 10-50 microns to obtain a self-made sample 1.

Example 2

The method comprises the following steps: performing ball milling on the lithium amide defective products until D50 is kept below 50 microns to obtain lithium amide particle powder;

step two: placing lithium amide particle powder in a reaction furnace with a stirring device, vacuumizing the reaction furnace until the vacuum degree is-0.1 mpa, raising the temperature of the reaction furnace to 250 ℃, introducing hydrogen sulfide gas into the reaction furnace to keep the pressure of the reaction furnace at 0.13mpa, and stirring for reacting for 4 hours;

step three: closing hydrogen sulfide gas, raising the temperature of the reaction furnace to 420 ℃, preserving the heat for 0.75 hour, and vacuumizing the reaction furnace to-0.1 mpa after the heat preservation is finished;

step four: introducing hydrogen sulfide gas again to keep the pressure of the reaction furnace at 0.75mpa, and heating to 430 ℃ for reaction for 4 hours;

step five: and performing ball milling, crushing and sieving on the reacted lithium sulfide, and controlling the D50 to be 10-50 microns to obtain a self-made sample 2.

Example 3

The method comprises the following steps: performing ball milling on the lithium amide defective products until D50 is kept below 50 microns to obtain lithium amide particle powder;

step two: placing lithium amide particle powder in a reaction furnace with a stirring device, vacuumizing the reaction furnace until the vacuum degree is-0.1 mpa, raising the temperature of the reaction furnace to 300 ℃, introducing hydrogen sulfide gas into the reaction furnace to keep the pressure of the reaction furnace at 0.15mpa, and stirring for reacting for 3 hours;

step three: closing hydrogen sulfide gas, raising the temperature of the reaction furnace to 400 ℃, preserving the heat for 1 hour, and vacuumizing the reaction furnace to-0.1 mpa after the heat preservation is finished;

step four: introducing hydrogen sulfide gas again to keep the pressure of the reaction furnace at 0.5mpa, and heating to 400 ℃ for reaction for 5 hours;

step five: and performing ball milling, crushing and sieving on the reacted lithium sulfide, and controlling the D50 to be 10-50 microns to obtain a self-made sample 3.

The lithium sulfide prepared by the preparation method can be applied to liquid batteries, and particularly can be applied to liquid battery electrolyte.

In order to compare the performance of the lithium sulfide prepared by the invention, the performance comparison of the conductivity and the cycle number of the battery is carried out as follows, wherein the self-made samples 1-3 are respectively the lithium sulfide prepared by the method of the invention, the comparative sample 1 is sigma purchased lithium sulfide, and the following table 1 is the performance comparison result of the self-made sample of the invention and the comparative sample:

table 1: comparison result of conductivity and battery cycle number of self-made sample and comparison sample

The performance comparison shows that the conductivity of the lithium sulfide prepared by the method is obviously higher than that of a comparative sample when the lithium sulfide is used for preparing the LPCLC, the cycle number of the prepared battery is obviously higher than that of the comparative sample, and the lithium sulfide prepared by the method has very excellent advantages.

As can be understood from the preparation method and the application of the high-purity lithium sulfide, the lithium sulfide is prepared by reacting lithium amide defective products with hydrogen sulfide. The lithium amide and the by-products thereof are easier to react with hydrogen sulfide compared with the lithium metal, and the lithium amide defective products are used for reacting with the hydrogen sulfide, so that the reaction progress of the lithium metal and the hydrogen sulfide is accelerated, and a small amount of lithium nitrogen compounds involved in the reaction have high electronic conductivity, so that the prepared lithium sulfide can achieve the performance of enhancing the electronic conductivity when used as a sulfide electrolyte. But also greatly improves the economic benefit for recycling the lithium amide defective products.

And the lithium sulfide obtained by the preparation method is applied to the electrolyte of the liquid battery to prepare the LPCCL, so that the conductivity and the battery cycle number are greatly improved.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.