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Liquid-phase co-precipitation preparation method of lithium iron phosphate cathode material

A technology of lithium iron phosphate and positive electrode materials, which is applied in the direction of battery electrodes, electrical components, circuits, etc., can solve the problems of poor charging and discharging performance of materials at high currents, difficulty in controlling product appearance, and high energy consumption in production, and achieves the goal of manufacturing The process is easy to control, the sintering time is shortened, and the cost is low

Inactive Publication Date: 2013-03-20
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the production process of industrialized lithium ferrous phosphate is mainly solid phase method, which has long sintering time (mostly more than 10 hours), high production energy consumption, difficult to control the shape of the product, excessive particle size, and material distortion. Disadvantages such as poor performance of high-current charging and discharging

Method used

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  • Liquid-phase co-precipitation preparation method of lithium iron phosphate cathode material
  • Liquid-phase co-precipitation preparation method of lithium iron phosphate cathode material
  • Liquid-phase co-precipitation preparation method of lithium iron phosphate cathode material

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Effect test

Embodiment 1

[0029] (1) Prepare NH with a concentration of 0.5 mol / L ferrous sulfate aqueous solution and 0.5 mol / L ammonium carbonate aqueous solution each with a pH of 7.5 3 100mL aqueous solution;

[0030] Add the above-mentioned NH into the reactor equipped with mechanical stirring, inert gas inlet and outlet and pH meter 3 200 mL of the aqueous solution was used as the mother liquor, then 0.58 g of citric acid was added as an antioxidant, and nitrogen protection was introduced. The ferrous sulfate aqueous solution and the ammonium carbonate aqueous solution were slowly added dropwise at the same time at a stirring speed of 800 revolutions / min, and the dropping speed was 2 mL / min. Fine-tune the flow rate of the two solutions to control the pH of the reaction solution to maintain between 7.5-9.5, and continue to stir and react for 0.5 hours after dripping to obtain a white ferrous carbonate precipitate; filter the ferrous carbonate precipitate and wash until it is neutral for use;

[0031] (2...

Embodiment 2

[0036] (1) Prepare 500 mL of ferrous chloride aqueous solution with a concentration of 3 mol / L and sodium carbonate aqueous solution with a concentration of 3 mol / L, NH with a pH of 8.5 3 25mL aqueous solution;

[0037] Add the above-mentioned NH into the reactor equipped with mechanical stirring, inert gas inlet and outlet and pH meter 3 The aqueous solution is used as the mother liquor, then 0.17g of oxalic acid is added, and nitrogen protection is introduced. The above-mentioned ferrous chloride aqueous solution and sodium carbonate aqueous solution are slowly added dropwise at a stirring speed of 2000 revolutions / min. The dropping rate is 0.5 mL / min. The flow rate of the solution is controlled to maintain the pH value of the reaction solution between 7.5-9.5; after dripping, continue to stir and react for 1.5 hours to obtain a white precipitate of ferrous carbonate; filter and wash the precipitate of ferrous carbonate until it is neutral for use;

[0038] (2) Quickly transfer th...

Embodiment 3

[0042] (1) Prepare 2000 mL each of ferrous nitrate aqueous solution with a concentration of 1.5 mol / L and potassium carbonate aqueous solution with a concentration of 1.5 mol / L, and NH with a pH of 9.5 3 150mL aqueous solution;

[0043] Add the above-mentioned NH into the reactor equipped with mechanical stirring, inert gas inlet and outlet and pH meter 3 The aqueous solution was used as the mother liquor, then 1.74 g of ascorbic acid was added, and nitrogen protection was introduced. The ferrous nitrate aqueous solution and the potassium carbonate aqueous solution were slowly added dropwise at a stirring speed of 1500 rpm at a rate of about 1.5 mL / min, and the two solutions were fine-tuned The flow rate control reaction solution pH value is maintained between 7.5-9.5; after dripping, continue to stir and react for 1 hour to obtain white ferrous carbonate precipitate; filter and wash the ferrous carbonate precipitate to neutral for use;

[0044] (2) Transfer the ferrous carbonate ob...

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Abstract

The invention discloses a liquid-phase co-precipitation preparation method of a lithium iron phosphate cathode material and belongs to the technical field of preparation of chemical materials. The method comprises the following steps of: using a controlled crystallization technology to prepare ferrous carbonate; with the newly prepared ferrous carbonate as an iron source, phosphoric acid as a phosphorus source and lithium hydroxide or lithium carbonate as a lithium source, preparing a lithium iron phosphate precursor by a liquid-phase co-precipitation method; drying, coating with carbon and sintering to obtain the lithium iron phosphate cathode material. The method disclosed by the invention better overcomes the shortcomings in the liquid-phase method that of Fe2<+> is oxidized easily and pH value of the solution is instable; and the prepared product is high in purity, uniform in distribution, and micron or nano-sized in granularity; the precursor which is small in granularity and contains various elements which are uniformly dispersed is more beneficial to the high-temperature solid-phase reaction, and is capable of shortening the sintering duration and reducing the energy consumption. The liquid-phase co-precipitation preparation method of the lithium iron phosphate cathode material has the advantages that used raw materials are simple and easily available, cost is low, and the preparation process can be controlled easily; therefore, the preparation method is applicable to massive industrial production.

Description

Technical field [0001] The invention belongs to the technical field of chemical material preparation, and particularly relates to a liquid phase co-precipitation preparation method of lithium iron phosphate cathode material. Background technique [0002] Lithium iron phosphate with an olivine structure is safer to use as a lithium-ion battery cathode material, and the structure is more stable. It solves the hidden safety problems of traditional lithium battery materials, lithium cobalt oxide and lithium manganate; lithium iron phosphate batteries are currently One of the safest lithium-ion batteries in the world. The theoretical capacity of the lithium iron phosphate battery can reach 170 mAh / g, and the life span is extremely long, and the number of cycles is high. The lithium iron phosphate battery also does not contain any heavy metals and rare metals, is non-toxic, non-polluting, and is an absolute green battery. In addition, lithium iron phosphate has excellent fast charge ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCY02E60/12Y02E60/10
Inventor 尚玉明赵骁王要武方谋谢晓峰王树博王金海
Owner TSINGHUA UNIV
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