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Reversed phase lithium inserting process of preparing poly crystal LiFePO4 nano powder material

A nano-powder, NH4H2PO4 technology, applied in chemical instruments and methods, active material electrodes, inorganic chemistry, etc., can solve problems such as low purity, uneven distribution, high carbon content of materials, and achieve stable precipitation and rapid formation Effect

Inactive Publication Date: 2005-10-19
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the material prepared by this method has the disadvantage of high carbon content
[0007] Prosini et al. used ferrous ammonium sulfate, ammonium dihydrogen phosphate and hydrogen peroxide to directly generate precipitation, and then intercalated lithium. However, this synthetic material has disadvantages such as low purity (easy to produce iron oxide), large particles, and uneven distribution.

Method used

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  • Reversed phase lithium inserting process of preparing poly crystal LiFePO4 nano powder material
  • Reversed phase lithium inserting process of preparing poly crystal LiFePO4 nano powder material
  • Reversed phase lithium inserting process of preparing poly crystal LiFePO4 nano powder material

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Measure 500ml of n-heptane and put it in a beaker, and slowly add 120g of surfactant ST with electromagnetic stirring. Measure 1.5M FeCl 3 40ml of aqueous solution, 1.5mL of glacial acetic acid was added dropwise, and then the mixed liquid was added dropwise into the oil phase liquid of n-heptane, and the uniform solution was an orange-red turbid liquid. Measure 13ml of n-butanol, add dropwise to the turbid liquid, then the liquid becomes clear and transparent, and finally forms a W / O microemulsion liquid. 60ml, 1.5M NH 4 h 2 PO 4Mix with 15ml, 0.5M sodium acetate solution evenly, add evenly and slowly with a burette, the solution system gradually changes from orange-red transparent to orange-red turbid, and finally becomes a white milky dispersion solution system. Heat the solution system to 70°C and keep it warm for 10 minutes, and the oil and water of the solution system are separated. Wash with acetone, soak the aqueous phase, and collect the precipitate. Dry ...

Embodiment 2

[0036] Measure 500ml of n-heptane and put it in a beaker, and slowly add 120g of surfactant ST with electromagnetic stirring. Measure 0.1M FeCl 3 40ml of aqueous solution, 2.5mL of glacial acetic acid was added dropwise, and then the mixed system was added dropwise into the oil phase liquid of n-heptane, and the solution became an orange-red turbid liquid after being uniform. Measure 5ml of n-butanol, add dropwise to the turbid liquid, then the system becomes clear and transparent, and finally forms a W / O microemulsion liquid. 80ml of 0.8M NH 4 h 2 PO 4 Mix evenly with 20ml 0.8M lithium acetate solution, add evenly and slowly with a burette, the solution gradually changes from orange-red transparent to orange-red turbid, and finally becomes a white milky dispersed solution system. Heat the system to 70°C and keep it warm for 10 minutes, and the oil and water of the solution system are separated. Wash with acetone, soak the aqueous phase, then collect the precipitate, and ...

Embodiment 3

[0038] Measure 500ml of n-heptane and put it in a beaker, and slowly add 120g of surfactant ST with electromagnetic stirring. Measure 0.05M FeCl 3 40ml of aqueous solution, 4mL of glacial acetic acid was added dropwise, and then the mixed liquid was added dropwise to the oil phase liquid of n-heptane, the liquid gradually became clear and transparent, and finally directly formed a W / O microemulsion liquid. 60ml 1M NH 4 h 2 PO 4 Mix evenly with 30ml 1M potassium acetate solution, add evenly and slowly with a burette, the solution gradually changes from orange-red transparent to orange-red turbid, and finally becomes a white milky dispersion system. Heat the liquid to 70°C and keep it warm for 10 minutes. The oil and water in the system are separated. Wash with absolute ethanol, soak the water phase, then collect the precipitate, and dry the precipitate at 300°C for 12 hours. The material was then soaked in 1M LiI for 24 hours, filtered, washed and the precipitate collected...

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Abstract

The present invention is reversed phase lithium inserting process of preparing polycrystal nano LiFePO4 powder material. Mixed surfactant ST of Span-80 and Tween-80 is added slowly into n-heptane, and mixed water solution of FeCl3 and glacial acetic acid and n-butanol are added to reversed phase microemulsion of FeCl3; the mixed solution of NH4H2PO4 and anhydrous glacial acetic acid and the microreactor of the microemulsion is utilized to prepare deposited nano size FePO4 grains; and LiI is inserted to obtain nano LiFePO4 powder finally. The present invention has the advantages of low synthesis temperature, and small size, great specific surface area and high activity of the synthesized material. The LiFePO4 powder material is suitable for use in producing lithium ion cell.

Description

technical field [0001] The invention belongs to the field of nanomaterial preparation, in particular to a method for preparing polycrystalline LiFePO by reverse phase lithium insertion method. 4 The method of nanopowder material. Background technique [0002] LiFePO 4 The material has the characteristics of cheap, non-toxic, non-hygroscopic, good environmental compatibility, rich mineral resources, high capacity (theoretical capacity is 170mAh / g, energy density is 550Wh / Kg), and good stability. It is one of the most potential alternative materials for lithium battery cathode materials. It has broad application prospects and great market demand. There are several synthetic methods: [0003] Solid-phase synthesis method: JP2000294238 mixes ferrous oxalate, lithium carbonate and diammonium hydrogen phosphate as initial materials and then calcines at high temperature for a long time. EP1193786 uses lithium phosphate and ferrous phosphate as initial materials for mixed calci...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G49/00H01M4/58H01M10/24
CPCY02E60/124Y02E60/10
Inventor 张中太卢俊彪唐子龙康凯沈万慈
Owner TSINGHUA UNIV
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