Method for preparing lithium iron phosphate in ionic eutectic mixture

A technology of eutectic mixture and lithium iron phosphate, applied in phosphorus compounds, chemical instruments and methods, inorganic chemistry, etc., to achieve the effects of simple preparation, not easy to deliquescence, and avoiding high temperature restrictions

Active Publication Date: 2012-06-13
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Currently, LiFePO is prepared in the ionic eutectic mixture system 4 not yet reported

Method used

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  • Method for preparing lithium iron phosphate in ionic eutectic mixture
  • Method for preparing lithium iron phosphate in ionic eutectic mixture
  • Method for preparing lithium iron phosphate in ionic eutectic mixture

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] 12.012g urea and 13.962g choline chloride (molar ratio 2:1) were mixed at room temperature to form a eutectic mixture, and 0.01 mole Li 2 CO 3 , 0.02 mole of ferrous oxalate, and 0.02 mole of ammonium dihydrogen phosphate are sequentially added to a stainless steel reactor lined with polytetrafluoroethylene, and the molar ratio of the reactants is Li 2 CO 3 : FeC 2 o 4 2H 2 O: NH 4 h 2 PO 4 :DES=0.5:1:1:15. After sealing, the reaction kettle was put into a homogeneous reactor at a speed of 10 rpm for crystallization reaction at 180° C. for 72 hours. After the reaction was completed, the reactor was taken out and cooled to room temperature. The resulting crystallized product was taken out, washed with alcohol and deionized water, filtered, and dried to obtain LiFePO 4 Powder.

Embodiment 2

[0046] 17.218g of imidazolone and 23.108g of choline iodide (molar ratio 2:1) were mixed at room temperature to form a eutectic mixture, followed by 0.02 mole of lithium chloride, 0.02 mole of ferrous chloride, and 0.02 mole of ammonium dihydrogen phosphate Add it to a stainless steel reactor lined with polytetrafluoroethylene, and the molar ratio of the reactants is LiCl:FeCl 2 : NH 4 h 2 PO 4 : DES = 1: 1: 1: 15, after sealing, put the reaction kettle into a homogeneous reactor at a speed of 5 rpm, and conduct a crystallization reaction at 150° C. for 120 h. After the reaction was completed, the reactor was taken out and cooled to room temperature. The resulting crystallized product was taken out, washed with alcohol and deionized water, filtered, and dried to obtain LiFePO 4 Powder.

Embodiment 3

[0048] Mix 12.670g of oxalic acid and 13.962g of choline chloride (molar ratio 1:1) at room temperature to form a eutectic mixture, add 0.02 mole of LiOH, 0.02 mole of ferrous oxalate, and 0.02 mole of diammonium hydrogen phosphate to the lining in sequence In the stainless steel reactor of polytetrafluoroethylene, the molar ratio of reactants is LiOH:FeC 2 o 4 2H 2 O:(NH 4 ) 2 HPO 4 : DES = 1: 1: 1: 10, after sealing, put the reaction kettle into a homogeneous reactor at a speed of 15 rpm, and conduct a crystallization reaction at 200° C. for 90 h. After the reaction was completed, the reactor was taken out and cooled to room temperature. The resulting crystallized product was taken out, washed with alcohol and deionized water, filtered, and dried to obtain LiFePO 4 Powder.

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Abstract

The invention discloses a method for preparing lithium iron phosphate serving as a lithium ion battery cathode material in an ionic eutectic mixture, which belongs to the technical field of preparation of electrochemical power supply materials. In the method, an ionic eutectic mixture obtained by compounding urea/carboxylic acid/alcohols with a quaternary ammonium salt and organic amine or an organic alkali serving as a regulating agent is taken as a reaction solvent as well as a template agent, and pure-phase lithium iron phosphate with high crystalizing performance is directly obtained with an ionic thermosynthesis method. Compared with synthesis of lithium iron phosphate by taking an imidazole ionic liquid as a solvent, the method has the advantages of higher easiness in designing and synthesizing quaternary ammonium cations with excellent template functions in the ionic eutectic mixture, effective adjustment and control of physical and chemical properties through a donor of hydrogen bonds, low-price and readily available raw materials, environmental compatibility, biodegradability, insensitivity to water and greater convenience for using; compared with synthesis of lithium iron phosphate with a high-temperature molten salt method, the method has the advantage of lower melting temperature of the ionic eutectic mixture; and compared with synthesis of lithium iron phosphate with a hydro-thermal method, the method has the advantage of higher safety due to extremely low steam pressure. The invention provides a novel method for preparing a lithium iron phosphate cathode material. The method has a wide application prospect in the field of lithium ion battery cathode materials.

Description

technical field [0001] The invention belongs to the technical field of preparation of electrochemical power source materials, and in particular relates to a method for preparing lithium iron phosphate, a cathode material for lithium ion batteries, in an ionic eutectic mixture. technical background [0002] In 2004, Professor Russell Morris' research group at the University of St Andrews (St. Andrews) in the United Kingdom took advantage of the fact that the ionic liquid system has almost no vapor pressure, and used imidazole compounds (or low melting point organic salt systems - choline chloride / urea) as both The solvent has the characteristics of template effect, and four kinds of aluminum phosphate framework materials with different structures were synthesized under different synthesis conditions. In 2006, they compounded 1,3-dimethylurea, imidazolone, acrylic acid and choline chloride respectively, and used the formed low-melting mixture as an ion-like thermal reaction me...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45
Inventor 罗绍华吴海艳田勇李辉诸葛福长
Owner NORTHEASTERN UNIV
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