Method for measuring content of iron element in different valence states in lithium iron phosphate anode material

A technology for lithium iron phosphate and positive electrode materials, which can be used in chemical analysis by titration, analysis by making materials react chemically, and material analysis by observing the influence of chemical indicators, etc., which can solve the safety hazard of elemental iron etc. to achieve the effect of convenient operation, simple method and reliable results

Inactive Publication Date: 2009-07-01
湖北盐光能源科技有限公司 +2
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Problems solved by technology

In some cases, LiFePO 4 There may also be elemental iron as an impurity in the p...

Method used

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Embodiment Construction

[0031] 1. Determination of total iron (potassium dichromate titration method)

[0032] The basic principle of iron total amount determination in the inventive method is: with acid (such as hydrochloric acid) acid dissolve lithium ferrous phosphate cathode material, then add stannous chloride, if there is Fe 3+ , Fe 3+ will be reduced to Fe by stannous chloride 2+ ; Then titrate Fe with potassium dichromate 2+ (including Fe produced by the reaction of elemental iron with acid 2+ 、LiFePO 4 Fe produced after acid dissolution 2+ and Fe 3+ Fe obtained after being reduced 2+ ), the measured iron is the sum of ferrous iron, elemental iron and ferric iron. The basic reaction process is as follows:

[0033] 2Fe 3+ +Sn 2+ +6Cl - →2Fe 2+ +SnCl 6 2

[0034] sn 2+ +4Cl - +2HgCl 2 →SnCl 6 2- +Hg 2 Cl 2 ↓

[0035] 6Fe 2+ +Cr 2 o 7 2- +14H + →6Fe 3+ +2Cr 3+ +7H 2 o

[0036] Analysis steps:

[0037] Weigh 1.0000g of LiFePO 4 Put the / C sample in a 250ml beaker...

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Abstract

The invention provides a measurement method for the contents of iron elements of different valence states in lithium iron phosphate anode, comprising: dissolving lithium iron phosphate anode sample via acid; adding stannous chloride to reduce ferric iron to ferrous iron; titrating ferrous ion via potassium dischromate, thereby obtaining the total ion weight; under protective gas, reacting lithium iron phosphate anode with ferric chloride, dissolving via acid, titrating ferrous ion via potassium dischromate, thereby obtaining the total weight of ferric iron and ferrous iron; reacting lithium iron phosphate anode with dilute hydrochloric acid, dissolving via acid, and titrating ferrous ion via potassium dischromate, thereby obtaining the content of ferric iron and pure Fe. The measurement method has simple process, simple operation and reliable result, and can provide basis for the quality judgment of LiFePO4 anode.

Description

technical field [0001] The invention relates to a detection technology for the quality of battery cathode materials, in particular to a detection technology for the content of divalent iron, trivalent iron and elemental iron in the lithium iron phosphate cathode material. Background technique [0002] Due to the characteristics of high cell voltage, high energy density, and safe and reliable use, lithium-ion batteries have been widely used in mobile phones, notebook computers, electronic instruments, UPS, and various portable electric tools. Since lithium cobalt oxide batteries were first launched on the market, lithium batteries have been rapidly promoted due to their electrical performance advantages. However, due to the lack of cobalt resources, the price of lithium cobalt oxide is high, the thermal stability of lithium cobalt oxide is poor, and cobalt is harmful to the environment. These unfavorable factors limit the application of lithium cobalt oxide. At present, the ...

Claims

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Application Information

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IPC IPC(8): G01N21/77G01N31/16
Inventor 欧阳曦万里城李启孙鸿飞刘玉平
Owner 湖北盐光能源科技有限公司
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