CN-122010058-A - Preparation method of liquid-phase purified and impurity-removed high-purity lithium sulfide, preparation method of sulfide solid electrolyte material and power battery

CN122010058ACN 122010058 ACN122010058 ACN 122010058ACN-122010058-A

Abstract

The present disclosure provides a preparation method of high purity lithium sulfide by liquid phase purification and impurity removal, a preparation method of sulfide solid electrolyte material and a power battery, wherein the preparation method of high purity lithium sulfide by liquid phase purification and impurity removal comprises the following steps of dissolving lithium hydroxide in deionized water, and passing through a stepped resin column component and a nanofiltration membrane to obtain a precursor purification liquid; reacting sodium sulfide with dilute sulfuric acid to obtain hydrogen sulfide gas, dehydrating and deoxidizing, introducing hydrogen sulfide into the precursor purified liquid to react to obtain lithium sulfide slurry, evaporating and concentrating the lithium sulfide slurry under the protection of inert gas, crystallizing and separating to obtain lithium sulfide crystals, and calcining the lithium sulfide crystals to obtain high-purity lithium sulfide. The step resin column component and the nanofiltration membrane are used for deep purification, dehydration and deoxidation treatment are carried out on the hydrogen sulfide gas, the purity and the yield of lithium sulfide products are improved, part of water is removed by the nanofiltration membrane, the evaporation time is shortened, and the yield loss caused by deterioration is reduced.

Inventors

LIU YINING
LI HONGJIAN
WU JIAWEI
DUAN ZHICHAO
LIAO YIPENG

Assignees

深圳智圣能源科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (10)

1. The preparation method of the high-purity lithium sulfide by liquid phase purification and impurity removal is characterized by comprising the following steps of: Dissolving lithium hydroxide in deionized water to obtain a lithium hydroxide solution, wherein the purity of the lithium hydroxide is more than 98%; The lithium hydroxide solution sequentially passes through a step resin column assembly and a nanofiltration membrane to obtain precursor purified liquid, wherein the step resin column assembly comprises a pretreatment resin column, a deep purification resin column and a fine purification resin column which are sequentially arranged, the pretreatment resin column is used for primarily removing impurities from an initial lithium hydroxide solution and rapidly adsorbing most of calcium ions and magnesium ions, the deep purification resin column is used for receiving the solution subjected to pretreatment and performing deep purification to further reduce the concentration of the calcium ions and the magnesium ions, the fine purification resin column is used for performing deep impurity removal on the solution subjected to the deep purification to ensure that the content of the calcium ions and the magnesium ions in effluent reaches a preset standard, and the nanofiltration membrane is used for intercepting and removing sulfate ions; Mixing sodium sulfide with dilute sulfuric acid for reaction to obtain hydrogen sulfide gas, and dehydrating and deoxidizing the hydrogen sulfide gas to obtain purified hydrogen sulfide raw material gas; Introducing the hydrogen sulfide raw material gas into the precursor purifying liquid, and reacting under the heating condition to obtain lithium sulfide slurry; Evaporating and concentrating the lithium sulfide slurry under the protection of inert gas, crystallizing and centrifugally separating to obtain lithium sulfide crystals; And carrying out vacuum calcination and crushing on the lithium sulfide crystal to obtain high-purity lithium sulfide.
2. The method for producing high purity lithium sulfide by liquid phase purification and impurity removal according to claim 1, wherein the pretreatment resin column comprises at least one chelating type cation exchange resin column, the chelating type cation exchange resin column of the pretreatment resin column has an aspect ratio of (1.5-3): 1, the deep purification resin column comprises at least one chelating type cation exchange resin column, the chelating type cation exchange resin column of the deep purification resin column has an aspect ratio of (0.8-1): 1, the finishing resin column comprises at least one chelating type cation exchange resin column, and the finishing resin column has an aspect ratio of (0.5-0.8): 1.
3. The method for producing high purity lithium sulfide by liquid phase purification and impurity removal according to claim 1, wherein sodium sulfide is mixed with dilute sulfuric acid to obtain hydrogen sulfide gas, and the hydrogen sulfide gas is subjected to dehydration and deoxidation treatment to obtain hydrogen sulfide raw material gas, comprising the steps of: Mixing the sodium sulfide solid with dilute sulfuric acid, and reacting at 45-75 ℃ to generate hydrogen sulfide gas, wherein the concentration of the dilute sulfuric acid is 10-18 wt%; Dehydrating the hydrogen sulfide gas through a molecular sieve dehydrator; and deoxidizing the hydrogen sulfide gas by a palladium carbon deoxidizer to obtain high-purity hydrogen sulfide gas.
4. The method for producing high purity lithium sulfide by liquid phase purification and impurity removal according to claim 1, wherein the hydrogen sulfide raw material gas is introduced into the precursor purification liquid and reacted under heating conditions to obtain lithium sulfide slurry, and the heating temperature is 105 ℃ to 120 ℃.
5. The method for producing high purity lithium sulfide by liquid phase purification and impurity removal according to claim 1, wherein the molar ratio of lithium hydroxide to hydrogen sulfide is 2:1.02 to 2:1.05 by introducing the hydrogen sulfide raw material gas into the precursor purification liquid.
6. The method for producing high purity lithium sulfide by liquid phase purification and purification according to claim 1, wherein the evaporation temperature of the evaporation concentration is 100 ℃ to 105 ℃ and the crystallization temperature is 40 ℃ to 55 ℃.
7. The method for producing high purity lithium sulfide by liquid phase purification and purification according to claim 1, wherein when the lithium sulfide crystal is vacuum calcined, the temperature of the vacuum calcination is 200 ℃ to 700 ℃, and the vacuum degree of the vacuum calcination is less than 50Pa.
8. The method for preparing the high-purity lithium sulfide by liquid phase purification and impurity removal according to claim 1, wherein the method for preparing the high-purity lithium sulfide by liquid phase purification and impurity removal prepares the high-purity lithium sulfide by a high-purity lithium sulfide preparation system, and the high-purity lithium sulfide preparation system comprises a lithium hydroxide purification unit, a hydrogen sulfide preparation unit, a lithium sulfide reaction unit, a deep purification unit and a post-treatment unit; The lithium hydroxide purifying unit comprises a dissolving tank, a stepped resin column component and a nanofiltration membrane component which are sequentially connected, and is used for dissolving lithium hydroxide, and sequentially carrying out resin exchange purification and nanofiltration treatment on the obtained solution to obtain precursor purifying liquid; The hydrogen sulfide preparation unit comprises a sodium sulfide feeding device, a dilute sulfuric acid metering tank, a reaction kettle, a dehydration device and a deoxidizing device which are connected in sequence, and is used for enabling sodium sulfide to react with dilute sulfuric acid to generate hydrogen sulfide gas, and sequentially dehydrating, deoxidizing and purifying the gas to obtain purified hydrogen sulfide gas; The precursor purifying liquid and the purified hydrogen sulfide gas are conveyed into the lithium sulfide reaction unit to react to generate lithium sulfide slurry, and the lithium sulfide slurry is sequentially treated by the deep purifying unit and the post-treatment unit to obtain high-purity lithium sulfide.
9. A method for preparing a sulfide solid electrolyte material, which is characterized in that the method for preparing high-purity lithium sulfide by liquid phase purification and impurity removal is adopted to prepare lithium sulfide, the lithium sulfide and phosphorus pentasulfide or halide are mixed and reacted, and the sulfide solid electrolyte material is obtained through mechanical ball milling and heat treatment.
10. A power cell comprising the sulfide solid state electrolyte material obtained in claim 9.

Description

Preparation method of liquid-phase purified and impurity-removed high-purity lithium sulfide, preparation method of sulfide solid electrolyte material and power battery Technical Field The disclosure relates to the technical field of battery material preparation, in particular to a preparation method of high-purity lithium sulfide by liquid phase purification and impurity removal, a preparation method of sulfide solid electrolyte material and a power battery. Background Lithium sulfide is a solid electrolyte material of sulfide, a core raw material of a lithium-sulfur battery, and its purity directly affects ion conductivity and cycle life of the battery's performance. The preparation method of the lithium sulfide mainly comprises the steps of adopting a direct metal lithium vulcanization method, wherein the metal lithium has high price, is easy to burn and has poor safety; The hydrogen sulfide method is adopted, the raw material cost is low, but impurities such as calcium, magnesium, sulfate radical, K, na and the like in lithium hydroxide can enter the product, so that the purity is difficult to improve. The lithium hydroxide is subjected to impurity removal by a precipitation method, the impurity removal capability of the impurity removal process is limited, the impurity content is difficult to control stably, and a precipitant such as Na 2CO3、Ba(NO3)2 is introduced by impurity removal, so that new Na +、Ba2+ pollution is brought, and the obtained lithium sulfide is subjected to the technical problems of incomplete impurity removal, low product purity, large yield loss and the like. A preparation method of high-purity lithium sulfide is disclosed in a comparison document CN202510687503.9, and comprises the steps of putting lithium hydroxide and pure water into a reaction kettle, replacing air in the reaction kettle with nitrogen, starting the reaction kettle to stir and heat, starting to introduce quantitative hydrogen sulfide gas from the bottom of the reaction kettle, circulating the gas in the reaction kettle between liquid and gas space in the reaction kettle through a gas circulating pump, filtering the reaction liquid in the kettle when the temperature of the reaction liquid in the kettle is reduced to 20-30 ℃, flushing the residual solid in a nitrogen atmosphere, transferring the filtered solid into a drying box, and blowing and drying the filtered solid to be anhydrous by nitrogen to obtain the high-purity lithium sulfide. Impurities such as calcium, magnesium, sulfate radical, K, na and the like in the lithium hydroxide can enter the product, so that the purity is difficult to improve. Disclosure of Invention The purpose of the present disclosure is to overcome the shortcomings in the prior art, and to provide a method for preparing high-purity lithium sulfide, a method for preparing sulfide solid electrolyte material, and a power battery, which have high purity and reduced yield loss. The aim of the disclosure is achieved by the following technical scheme: A preparation method of high-purity lithium sulfide by liquid phase purification and impurity removal comprises the following steps: Dissolving lithium hydroxide in deionized water to obtain a lithium hydroxide solution, wherein the purity of the lithium hydroxide is more than 98%; The lithium hydroxide solution sequentially passes through a step resin column assembly and a nanofiltration membrane to obtain precursor purified liquid, wherein the step resin column assembly comprises a pretreatment resin column, a deep purification resin column and a fine purification resin column which are sequentially arranged, the pretreatment resin column is used for primarily removing impurities from an initial lithium hydroxide solution and rapidly adsorbing most of calcium ions and magnesium ions, the deep purification resin column is used for receiving the solution subjected to pretreatment and performing deep purification to further reduce the concentration of the calcium ions and the magnesium ions, the fine purification resin column is used for performing deep impurity removal on the solution subjected to the deep purification to ensure that the content of the calcium ions and the magnesium ions in effluent reaches a preset standard, and the nanofiltration membrane is used for intercepting and removing sulfate ions; Mixing sodium sulfide with dilute sulfuric acid for reaction to obtain hydrogen sulfide gas, and dehydrating and deoxidizing the hydrogen sulfide gas to obtain purified hydrogen sulfide raw material gas; Introducing the hydrogen sulfide raw material gas into the precursor purifying liquid, and reacting under the heating condition to obtain lithium sulfide slurry; Evaporating and concentrating the lithium sulfide slurry under the protection of inert gas, crystallizing and centrifugally separating to obtain lithium sulfide crystals; And carrying out vacuum calcination and crushing on the lithium sulfide crystal to obtain high-purity lithium