Method for testing mercury content in lithium ion battery graphite negative electrode material

Abstract

The invention discloses a method for testing mercury content in a graphite negative electrode material of a lithium ion battery, and relates to the technical field of battery material detection, and the method comprises the following steps: crushing the graphite negative electrode material, adding concentrated hydrochloric acid and deionized water, heating, dissolving, and filtering to obtain a filtrate; adding an aqueous solution of ammonium pyrrolidine dithiocarbamate into the filtrate, oscillating and uniformly mixing, then adding methyl isobutyl ketone, oscillating and uniformly mixing, standing and layering, removing an aqueous phase, and collecting an organic phase; transferring the organic phase into a glass volumetric flask, metering the volume by using methyl isobutyl ketone, and adding several drops of potassium permanganate solution before metering the volume to serve as a to-be-detected sample solution; preparing a sample blank solution and a standard sample solution, and determining by using a hydride atomic absorption spectrometry. According to the method disclosed by the invention, the Hg < 2 + > is transferred from a sample matrix by using the pyrrolidine dithiocarbamate and the methyl isobutyl ketone, so that serious matrix interference is avoided, and the detection stability and accuracy are further improved.

Description

technical field [0001] The invention relates to the technical field of battery material detection, in particular to a method for testing mercury content in lithium-ion battery graphite negative electrode materials. Background technique [0002] Since Sony Corporation developed lithium-ion batteries with carbon materials as negative electrodes, the capacity of batteries has continued to increase, which is largely due to the continuous improvement of carbon materials. Graphite is one of the most studied carbon materials for lithium-ion batteries, including natural graphite, artificial graphite and various graphitized carbons. Since these substances come from natural resources, they will bring various toxic and harmful substances, such as heavy metals, etc. The presence of mercury in heavy metals is the most harmful. Therefore, the GB / T 30836-2014 standard specifies the limit requirements for mercury and its compounds. [0003] There are many detection methods for mercury and...

AI Technical Summary

Problems solved by technology

However, in the prior art, the cold atomic absorption method is used to measure the mercury content. The pretreatment of the sample is relatively simple. Generally, it is directly measured after acid dissolution, and other components in the raw material will interfere with its determination.

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