A kind of determination method of silicon in silicon/carbon negative electrode material

Abstract

The invention relates to the technical field of analysis and measurement and especially relates to a measuring method of silicon in a lithium ion battery silicon / carbon anode material through flame atomic absorption spectrometry. The method particularly includes the steps of: carbonizing and ashing the silicon / carbon anode material, adding proper amounts of concentrated nitric acid, an ammonium fluoride water solution and a Triton-100 solution, and performing ultrasonic heating; cooling and filtering the liquid, adding proper amounts of a cesium chloride solution, a strontium chloride solution and the Triton-100 solution to a filtrate, and diluting the filtrate to constant volume by deionized water; and performing measurement through the flame atomic absorption spectrometry. The cesium chloride solution can inhibit high-temperature ionization of silicon, the strontium chloride solution can inhibit interference on silicon due to metal aluminum and phosphates during the measurement and analysis, and the Triton-100 solution can prolong the retention time of ground state atoms in the flame. The flame atomic absorption spectrometry has good selectivity, low spectral line interference, high analysis speed, simple operations, high accuracy and low application cost, so that the measuring method is suitable for the measurement of the content of silicon in the silicon / carbon anode material.

Description

technical field [0001] The invention relates to the technical field of analysis and testing, in particular to a method for determining silicon in silicon / carbon negative electrode materials of lithium-ion batteries by flame atomic absorption spectrometry. Background technique [0002] The negative electrode material of lithium ion battery is mainly graphite, but the capacity of graphite material is low, the theoretical capacity of graphite is 372mAh / g; based on the limitation of graphite capacity, and the theoretical capacity value of silicon is 4200mAh / g, the following The anode material made of metal silicon and silicon alloy has the advantages of low cost and high capacity. However, when silicon / carbon anode materials are mixed and prepared, the proportion of silicon and carbon will change greatly with the production process, which seriously affects the mass production of silicon / carbon anode materials. The silicon content of the material is analyzed and tested to contro...

AI Technical Summary

Problems solved by technology

However, when silicon / carbon anode materials are mixed and prepared, the proportion of silicon and carbon will change greatly with the production process, which seriously affects the mass production of silicon / carbon anode materials. The silicon content of the material is analyzed and tested to control the ratio of silicon to carbon in the production process to maintain consistency

[0003] The determination method of silicon in the silicon / carbon negative electrode material is not disclosed in the existing literature, and the conventional silicon content test methods generally include photometry, ICP-OES, AAS, etc., wherein: photometry, i.e. silicon molybdenum blue photometry, is applicable to Low content determination and analysis, such as the determination of silicon in GB6712 high-purity graphite products, but because of the interference of various metal ions, the test repeatability is poor, the operation is cumbersome, and the test cycle is long, so it is not suitable for the determination of silicon in silicon nickel / carbon negative electrode materials

ICP-OES has fast analysis speed and wide line shape range, but the cost of the instrument is high and the spectral line interference is serious

[0004] Among the existing test methods for analyzing silicon content in metal materials, flame atomic absorption method is rarely used. Because silicon element is a high-temperature element, nitrous oxide-acetylene flame method is generally used to measure silicon content by flame atomic absorption method at present; and silicon / Silicon in the carbon negative electrode material is covered by a large amount of carbon materials, it is difficult to completely dissolve it directly with acid, and the metal ions in the sample interfere with the determination of silicon, which seriously affects the accuracy of the determination of silicon content

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