Measuring method of divalent cobalt content in lithium cobalt oxide

A technology of lithium cobalt oxide and its determination method, which is applied in the direction of material analysis through observation of the influence on chemical indicators, and analysis through chemical reaction of materials, and can solve the problem of lack of determination of divalent cobalt content in lithium cobalt oxide Methods and other issues

Inactive Publication Date: 2010-03-31
SHENZHEN BAK BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, prior art lacks the assay method ...

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  • Measuring method of divalent cobalt content in lithium cobalt oxide
  • Measuring method of divalent cobalt content in lithium cobalt oxide
  • Measuring method of divalent cobalt content in lithium cobalt oxide

Examples

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Embodiment 1

[0040] The assay method of the divalent cobalt content in the lithium cobalt oxide of this example is to measure the total cobalt content and the trivalent cobalt ion content in the lithium cobalt oxide respectively, then subtract the trivalent cobalt ion content from the total cobalt content to obtain the lithium cobalt oxide Divalent cobalt content in lithium cobalt oxide; wherein, the assay method of total cobalt content in lithium cobalt oxide adopts ethylaminetetraacetic acid (EDTA) complexometric volumetric method; The assay method of trivalent cobalt ion content in lithium cobalt oxide adopts ferrous sulfate Ammonium redox titration method, the steps are as follows:

[0041] 1. Total cobalt content in lithium cobalt oxide

[0042] 1.1 Main reagents

[0043] Cobalt standard solution 0.05mol / L: Weigh 2.9500g of cobalt metal sheet (purity 99.98%), put it in a 250ml beaker, add a small amount of hydrochloric acid (P=1.19g cm -3 ) and hydrogen peroxide (30%, percent by wei...

Embodiment 2

[0088] The determination method of divalent cobalt content in the lithium cobalt oxide of this example adopts the iodometric method except that the determination method of the total cobalt content in the lithium cobalt oxide is the same as embodiment one.

[0089] The assay steps of total cobalt content in the lithium cobalt oxide of this example are as follows:

[0090] 1. Method summary:

[0091] co 2+ It can be oxidized to Co by iodine in ammoniacal solution (PH=9~10) containing ammonium nitrate 3+ , and generate stable green precipitate of nitric acid-iodine pentaammine cobalt with iodine. Excess iodine was titrated with standard sodium arsenite solution using starch as indicator. Its reaction formula is as follows:

[0092] 2Co 2+ +4NO 3 - +10NH 3 +I 2 →2〔Co(NH 3 ) 5 I〕(NO 3 ) 2 ↓

[0093] I 2 +AsO 3 3- +H 2 O→AsO 4 3- +2HI

[0094] Iron and aluminum can form hydroxide precipitates in ammonia solution and easily adsorb cobalt. At the same time, iron h...

Embodiment 3

[0110] The determination method of the divalent cobalt content in the lithium cobalt oxide of this example is the same as the first embodiment except that the determination method of the total cobalt content in the lithium cobalt oxide adopts the potassium ferricyanide redox titration method.

[0111] The assay steps of total cobalt content in the lithium cobalt oxide of this example are as follows:

[0112] 1. Method summary

[0113] In ammoniacal solution, the Co 2+ Oxidized to Co 3+ , an appropriate amount of potassium ferricyanide with Co 2+ Standard solution back titration.

[0114] co 2+ +【Fe(CN) 6 】 3- →Co 3+ +【Fe(CN) 6 】 4-

[0115] Under the conditions of this Act, Fe 2+ Easily oxidized to Fe under ammonia conditions 3+ , interference determination. However, adding ammonium citrate and ammonium sulfate to the mixed solution with ammonia water can eliminate interference.

[0116] 2 Instruments and main reagents

[0117] 2.1 ZD-2 type automatic potentiome...

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Abstract

The invention belongs to a measuring method of divalent cobalt content in lithium cobalt oxide in the metallic ion quantitative detection field; the measuring method is characterized in that: total cobalt content and trivalent cobalt ion content in the lithium cobalt oxide are respectively measured, and then the total cobalt content subtracts the trivalent cobalt ion content for obtaining the divalent cobalt content in lithium cobalt oxide; wherein, the measuring method of the total cobalt content in the lithium cobalt oxide adopts ethylenediamine tetraacetic acid (EDTA) chelatometrie volumetric method, an iodometry method or a potassium ferricyanide oxidimetry method, and the measuring method of the trivalent cobalt ion content in the lithium cobalt oxide adopts an ammonium ferrous sulfate oxidimetry method. The measuring method in the invention makes up the disadvantage that the prior art has no measuring method of divalent cobalt content in lithium cobalt oxide and provides a measuring method of divalent cobalt content in lithium cobalt oxide in the metallic, wherein the method has simple operation, easy judgment of a finishing point and accurate measuring result, thereby providing powerful reference for judging the purity of the lithium cobalt oxide products and ensuring the lithium cobalt oxide products to have good electro-chemical performance.

Description

Technical field: [0001] The invention belongs to the field of quantitative detection of metal ions, in particular to a method for measuring divalent cobalt content in lithium cobalt oxide. Background technique: [0002] Lithium cobalt oxide (LiCoO 2 ) has become a widely commercialized cathode material for lithium batteries due to its excellent electrochemical properties. The ratio of lithium to cobalt content in lithium cobalt oxide directly affects its layered structure integrity and electrochemical performance. How to quickly and accurately measure lithium cobalt content and valence state in the process of production and application to control its excellent performance is particularly important. With Co 3 o 4 and LiOH·H 2 O as raw material, LiCoO synthesized by microwave heating 2 , when the added Li and Co react completely, a stoichiometric LiCoO is generated 2 , Co should all be trivalent cobalt (Co 3+ ), instead of divalent cobalt (Co 2+ ). Conversely, if Li ...

Claims

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Application Information

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IPC IPC(8): G01N21/79
Inventor 刘玉梅
Owner SHENZHEN BAK BATTERY CO LTD
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