Method for rapidly determining content of free acid in lithium hexafluorophosphate product in non-aqueous system

A technology for rapid determination of lithium hexafluorophosphate, which is used in measurement devices, chemical method analysis, chemical analysis by titration, etc., can solve the problems of long measurement time, poor precision, low accuracy, etc., to improve quality and shorten detection time. , the effect of improving the detection efficiency

Inactive Publication Date: 2019-09-20
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The purpose of the present invention is to break through the above-mentioned three restrictive factors that have plagued the determination of free acid content in lithium hexafluorophosphate products for many years, and overcome the precision of acid-base titration, potentiometric titration and

Method used

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  • Method for rapidly determining content of free acid in lithium hexafluorophosphate product in non-aqueous system
  • Method for rapidly determining content of free acid in lithium hexafluorophosphate product in non-aqueous system
  • Method for rapidly determining content of free acid in lithium hexafluorophosphate product in non-aqueous system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Analytical test object: Lithium hexafluorophosphate electrolyte (solid) numbered LHFP-01. The determination steps are as follows:

[0031] (1) Accurately weigh the mass in the glove box as m s (about 1.000g) lithium hexafluorophosphate electrolyte sample, place the weighed sample in a dry polytetrafluoroethylene beaker;

[0032] (2) In the transfer chamber of the glove box, add 30 mL of lithium chloride-ethanol solution with a concentration of 0.50 mol / L to the polytetrafluoroethylene beaker, and then take out the beaker;

[0033] (3) Place the polytetrafluoroethylene beaker on the stirrer to stir, insert the pH indicating electrode pair and the working electrode pair, and connect the two with the acid-base coulometric titrator;

[0034] (4) After setting the electrolysis current, start the acid-base coulometric titrator, and the electrolysis will stop automatically at the titration end point, record the electrolysis time t and the electrolysis current I, and calculat...

Embodiment 2

[0036] Analysis and test object: Lithium hexafluorophosphate electrolyte solution numbered LHFP-12, which is composed of lithium hexafluorophosphate electrolyte and ethylene carbonate, with a concentration of 1mol / L. The determination steps are as follows:

[0037] (1) Add 30 mL of lithium chloride-ethanol solution with a concentration of 0.50 mol / L to a polytetrafluoroethylene beaker, place the beaker on a stirrer and stir, insert a pair of pH indicating electrodes and a pair of working electrodes, and mix the two with acid Alkaline coulometric titrator connected;

[0038] (2) Select a dry 5mL PE material syringe, take about 2mL of the lithium hexafluorophosphate electrolyte to be tested in the glove box, and seal the needle with a matching plastic sleeve. Transfer the syringe to the atmosphere and accurately weigh to 0.001g on an analytical balance;

[0039] (3) Quickly add about 1.000g of lithium hexafluorophosphate electrolyte into the above-mentioned polytetrafluoroethy...

Embodiment 3

[0042] Analysis and test object: Lithium hexafluorophosphate electrolyte solution numbered LHFP-13, which is composed of lithium hexafluorophosphate electrolyte, ethylene carbonate, dimethyl carbonate, and diethyl carbonate. The concentration of the lithium hexafluorophosphate electrolyte is 1mol / L, and the volume ratio of ethylene carbonate, dimethyl carbonate, and diethyl carbonate is 1:1:1. The assay procedure of this sample is basically the same as in Example 2.

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Abstract

The invention relates to a method for rapidly determining the content of a free acid in a lithium hexafluorophosphate product in a non-aqueous system. According to the method, a water-free supporting electrolyte solution is used as an electrolytic solution; the free acid in the lithium hexafluorophosphate product is titrated with alkaline ions electrolyzed by the electrolytic solution; the content of the free acid in the sample is calculated according to the faraday's law; and the whole detection process can be finished within 5 minutes, and a result can be obtained. With the method of the invention adopted, three bottlenecks, namely, the poor thermal stability of the lithium hexafluorophosphate, interference caused by hydrofluoric acid generated by the reaction of the lithium hexafluorophosphate with water, and little possibility of accurately measuring trace free acids, can be broken; problems such as low precision, low accuracy and long detection time of acid-base titration methods, potentiometric titration methods and etching methods which are commonly used in current industrial production and scientific research can be overcome. The method can be applied to a wide range of samples, can practically promote the analysis and detection levels of fluorine chemical industries and lithium ion battery industries, and further improve the quality of related industrial products.

Description

technical field [0001] The invention relates to the technical fields of analysis and detection and lithium ion batteries, in particular to a method for quickly measuring free acid content in lithium hexafluorophosphate products in a non-aqueous system. Background technique [0002] Lithium hexafluorophosphate (LiPF 6 ) The electrolyte consists of a lithium hexafluorophosphate electrolyte and a carbonate organic solvent. Due to the advantages of good ionic conductivity, long cycle life, high energy density, small self-discharge, no memory effect, and environmental protection, lithium hexafluorophosphate electrolyte has become the only commercially used lithium-ion battery electrolyte. [0003] However, lithium hexafluorophosphate has poor thermal stability and will slowly decompose PF 5 and Generated PF 5 react with water HF in turn catalyzes PF 5 React with water, thereby accelerating the decomposition of lithium hexafluorophosphate. When used as the electrolyte of ...

Claims

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Application Information

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IPC IPC(8): G01N27/42G01N31/16
CPCG01N27/423G01N31/164
Inventor 蔡宏伟黄偲睿屈德宇袁方赵经纬余乐刘蕊范超君
Owner WUHAN UNIV OF TECH
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