Method for preparing lithium iron phosphate in ionic eutectic mixture

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...

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