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CN-121978090-A - Method for detecting chloride ions in sulfide

CN121978090ACN 121978090 ACN121978090 ACN 121978090ACN-121978090-A

Abstract

The embodiment of the application discloses a method for detecting chloride ions in sulfide, which comprises the following steps of oxidizing S 2‑ which is easy to interfere by using an oxidant, dissolving sulfide in a solvent under an inert atmosphere, adding the oxidant to obtain a second solution, heating the second solution in a water bath under an alkaline condition to facilitate the decomposition of the residual oxidant, and evaporating and boiling a third solution under an acidic condition to form sulfur dioxide gas to escape, so that the interference of the sulfide ions is effectively reduced, thereby obviously reducing the error rate of detection, and having high repeatability and high test precision.

Inventors

  • LIU QIANG
  • Xiong Hougao
  • LUO WEN
  • Tu Huazhen
  • SHI QIHUA
  • WANG DONGWEI
  • WANG JINTAO
  • LV ZHENGZHONG

Assignees

  • 湖北金泉新材料有限公司

Dates

Publication Date
20260505
Application Date
20260106

Claims (10)

  1. 1. The method for detecting chloride ions in sulfide is characterized by comprising the following steps: Dissolving sulfide in a solvent under inert atmosphere to obtain a first solution; Adding an oxidant into the first solution to obtain a second solution; Heating the second solution in water bath under alkaline condition to obtain a third solution; Acidifying the third solution under an acidic condition, and evaporating and boiling to obtain a fourth solution; and testing the fourth solution by a colorimetry method to obtain the chloride ion content.
  2. 2. The method for detecting chloride ions in sulfide as set forth in claim 1, wherein, The sulfide comprises at least one of lithium sulfide and sulfur-containing solid electrolyte, and/or The solvent comprises one of water and dilute acid, and/or The inert atmosphere comprises any one of argon atmosphere, nitrogen atmosphere, helium atmosphere and neon atmosphere, and/or The oxidant comprises one of hydrogen peroxide and potassium permanganate.
  3. 3. The method for detecting chloride ions in sulfide as claimed in claim 2, wherein, The dilute acid comprises one of nitric acid, sulfuric acid, acetic acid, and phosphoric acid, and/or The concentration of the dilute acid is less than or equal to 50wt%.
  4. 4. The method for detecting chloride ions in sulfide as set forth in claim 1, wherein, The step of adding an oxidizing agent to the first solution comprises: And adding an oxidant into the first solution, wherein the oxidant is stopped when the temperature of the first solution is increased, and the oxidant is continuously added after the first solution is cooled until no exothermic phenomenon exists after the oxidant is added, so that the oxidant is stopped.
  5. 5. The method for detecting chloride ions in sulfide as set forth in claim 1, wherein, The pH value of the alkaline condition ranges from 7 to 14; Preferably, the pH of the alkaline condition has a value in the range of 9 to 12.
  6. 6. The method for detecting chloride ions in sulfide as set forth in claim 1, wherein, The value range of the temperature of the water bath heating is 50 o to 100 o ℃, and the value range of the time of the water bath heating is 0.5 to 5 hours; Preferably, the temperature of the water bath heating is in the range of 60 o C to 90 o C, and the time of the water bath heating is in the range of 2h to 3h.
  7. 7. The method for detecting chloride ions in sulfide as set forth in claim 1, wherein, The pH value of the acidic condition ranges from 2 to 6; Preferably, the pH of the acidic condition has a value in the range of 3 to 5; the acidification reaction time is 0.5min to 60min; Preferably, the acidification reaction time is 5min to 10min.
  8. 8. The method for detecting chloride ions in sulfide as set forth in claim 1, wherein, The evaporation amount of the evaporation boiling is 10wt% to 60wt% of the third solution; preferably, the evaporation boiling is performed with an evaporation amount of 30wt% to 50wt% of the third solution.
  9. 9. The method for detecting chloride ions in sulfide as set forth in claim 1, wherein, The detection method further comprises the following steps: Adding a dispersing agent into the fourth solution, and testing by a colorimetric method to obtain the content of chloride ions; wherein the dispersing agent comprises at least one of glycol, glycerol and absolute ethyl alcohol.
  10. 10. The method for detecting chloride ions in sulfide as set forth in claim 1, wherein, And the fourth solution is placed for more than one week, and the change rate of the chloride ion content is tested to be less than 2%.

Description

Method for detecting chloride ions in sulfide Technical Field The application relates to the technical field of ion content testing, in particular to a method for detecting chloride ions in sulfides. Background Chloride ion is one of the key impurities affecting material properties, especially in battery materials (e.g., sulfides, sulfide-based solid electrolytes), whose content directly affects electrochemical performance and safety. Currently, in the related art, a colorimetric method is mostly adopted to detect chloride ions in sulfides, a color compound is generated by the reaction of a color developing agent and the chloride ions, and a spectrophotometry is utilized for quantitative test. However, in this method, the sulfur ion (S 2-) competes with the developer for binding, resulting in unstable color reaction. Disclosure of Invention The application provides a method for detecting chloride ions in sulfide, which aims to solve the problem of unstable color development reaction caused by competitive combination of sulfide ions (S 2-) and a color developing agent. The application provides a method for detecting chloride ions in sulfide, which comprises the following steps: Dissolving sulfide in a solvent under inert atmosphere to obtain a first solution; Adding an oxidant into the first solution to obtain a second solution; Heating the second solution in water bath under alkaline condition to obtain a third solution; Acidifying the third solution under an acidic condition, and evaporating and boiling to obtain a fourth solution; and testing the fourth solution by a colorimetry method to obtain the chloride ion content. Optionally, in some embodiments of the application, the sulfide comprises at least one of lithium sulfide, a sulfur-containing solid electrolyte, and/or The solvent comprises one of water and dilute acid, and/or The inert atmosphere comprises any one of argon atmosphere, nitrogen atmosphere, helium atmosphere and neon atmosphere, and/or The oxidant comprises one of hydrogen peroxide and potassium permanganate. Optionally, in some embodiments of the application, the dilute acid comprises one of nitric acid, sulfuric acid, acetic acid, phosphoric acid, and/or The concentration of the dilute acid is less than or equal to 50wt%. Optionally, in some embodiments of the application, the step of adding an oxidizing agent to the first solution includes: slowly adding an oxidant into the first solution, wherein the temperature of the first solution is increased, namely, the oxidant is stopped being added, and the oxidant is continuously added after the first solution is cooled until no exothermic phenomenon exists after the oxidant is added, namely, the oxidant is stopped being added. Optionally, in some embodiments of the application, the pH of the alkaline condition ranges from 7 to 14; Preferably, the pH of the alkaline condition has a value in the range of 9 to 12. Optionally, in some embodiments of the present application, the temperature of the water bath heating ranges from 50 o C to 100 o C, and the time of the water bath heating ranges from 0.5h to 5h; Preferably, the temperature of the water bath heating is in the range of 60 o C to 90 o C, and the time of the water bath heating is in the range of 2h to 3h. Optionally, in some embodiments of the application, the pH of the acidic condition ranges from 0 to 7; Preferably, the pH of the acidic condition has a value in the range of 3 to 5; the acidification reaction time is 0.5min to 60min; Preferably, the acidification reaction time is 5min to 10min. Optionally, in some embodiments of the application, the pH of the acidic condition ranges from 2 to 6; Preferably, the pH of the acidic condition has a value in the range of 3 to 5; the acidification reaction time is 0.5min to 60min; Preferably, the acidification reaction time is 5min to 10min. Optionally, in some embodiments of the present application, the detection method further includes: Adding a dispersing agent into the fourth solution, and testing by a colorimetric method to obtain the content of chloride ions; wherein the dispersing agent comprises at least one of glycol, glycerol and absolute ethyl alcohol. Alternatively, in some embodiments of the application, the fourth solution is left for more than one week, and the rate of change of the chloride ion content is tested to be less than 2%. According to the embodiment of the application, the S 2- which is easy to interfere is oxidized by using the oxidant, sulfide is dissolved in the solvent under inert atmosphere, the oxidant is added to obtain the second solution, the second solution is heated in a water bath under alkaline condition, the residual oxidant is helpful to decompose, and the third solution is evaporated and boiled under acidic condition to form sulfur dioxide gas to escape, so that the interference of sulfur ions is effectively reduced, the error rate of detection is obviously reduced, and the repeatability and the testi