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Method for preparing Li Fe PO4 ball shape powder

A spherical powder and powder technology, applied in the field of material science, can solve the problems of small specific surface area, low material density, large specific surface area, etc., and achieve the effects of large specific surface area, high material yield, and low sintering temperature

Inactive Publication Date: 2005-08-03
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The object of the invention is to provide a LiFePO 4 The preparation method of spherical powder, which can solve the problems of low density, small specific surface area and poor conductivity of materials prepared by conventional preparation methods. It can be prepared on a large scale with good crystallinity. The powder is spherical in shape and narrow in distribution. High purity (except LiFePO 4 There is no impurity outside the coated hard carbon), the material has good conductivity, large specific surface area, and LiFePO with a large mass density 4 Spherical powder, which is also beneficial for LiFePO 4 Material battery manufacturing process

Method used

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  • Method for preparing Li Fe PO4 ball shape powder
  • Method for preparing Li Fe PO4 ball shape powder
  • Method for preparing Li Fe PO4 ball shape powder

Examples

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Effect test

Embodiment 1

[0032] Example 1: Calcining LiFePO 4 Precursor of the compound: Weigh ferrous oxalate 2 hydrate, lithium carbonate, and ammonium dihydrogen phosphate according to the molar ratio of 1:0.5:1, and use absolute ethanol as the ball milling medium to mill the mixture for 4 hours; Pretreatment in an inert atmosphere or a reducing atmosphere for 8 hours can obtain a solid phase material pretreatment powder A1, and Figure (1) is the XRD pattern of the pretreatment powder A1. Weigh 6 kg of A1, 0.6 kg of PVA, 5.4 liters of deionized water, and 72 ml of dispersant, place them in a container, and mill them on a rolling mill for 48 hours to obtain a slurry with good fluidity and stability. Send the slurry into the spray granulation tower, the feed rate is controlled at 12±2ml / min, the air flow rate of the nozzle is controlled by the pressure of the compressed air, which is 0.08-0.1Mpa, the air inlet temperature is about 300°C, and the outlet temperature is 100°C ~130°C. After collecting ...

Embodiment 2

[0033] Example 2: Calcining LiFePO 4Precursor: Weigh ferrous oxalate 2 hydrate, lithium carbonate, and ammonium dihydrogen phosphate according to the molar ratio, and add 0.8 at% magnesium oxalate 2 hydrate; ball mill the mixture for 8 hours with absolute ethanol as the ball milling medium; After drying, pretreat in an inert atmosphere or a reducing atmosphere at 400°C for 16 hours to obtain solid phase substance A2; weigh 6.5 kg of solid phase substance A2, 0.65 kg of PVA, 5.85 liters of deionized water, and 78 ml of dispersant, and place them in a container In the rolling mill, ball milling on the rolling mill for 4 days can obtain a slurry with good fluidity and stability; the slurry is sent to the spray granulation tower, the feed rate is controlled at 12±2ml / min, and the nozzle air flow is controlled by compressed air The pressure control is 0.08-0.1Mpa, the air inlet temperature is about 300°C, and the outlet temperature is 100-130°C; after collecting the dried powder, p...

Embodiment 3

[0034] Example 3: Calcining LiFePO 4 Precursor: Weigh ferrous oxalate 2 hydrate, lithium carbonate, and ammonium dihydrogen phosphate according to the molar ratio, and add 0.4 at% aluminum isopropoxide. The mixture was ball milled for 6 hours with absolute ethanol as the ball milling medium. The solid phase substance A3 can be obtained by pretreatment in an inert atmosphere or a reducing atmosphere at 350° C. for 10 hours after low-temperature drying. Weigh 36.2 kg of solid phase substance A, 0.62 kg of PVA, 5.25 liters of deionized water, and 73 ml of dispersant, place them in a container, and ball mill them on a rolling mill for 3 days to obtain a slurry with good fluidity and stability. Send the slurry into the spray granulation tower, the feed rate is controlled at 12±2ml / min, the air flow rate of the nozzle is controlled by the pressure of the compressed air, which is 0.08-0.1Mpa, the air inlet temperature is about 300°C, and the outlet temperature is 100°C ~130°C. Aft...

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Abstract

The preparation process of spherical LiFePO4 powder includes pre-synthesizing doped or blank nanometer LiFePO4 powder and ball milling the powder, adhesive, dispersant and water to obtain slurry; spray pelletizing and drying, processing under reducing atmosphere, and final sintering the powder under reducing or inert atmosphere to obtain carbon black spherical LiFePO4 powder of nanometer level size. The present invention has short preparation process, low sintering temperature and low power consumption, and the preparation polycrystal powder has narrow grain size distribution, spherical form and improved electronic conducting performance.

Description

technical field [0001] The invention relates to a high electrochemical performance secondary lithium ion battery or battery positive electrode material spherical LiFePO for power energy 4 The preparation method of powder belongs to the field of material science. 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 cathode materials. It has broad application prospects and great market demand. Currently there are several synthetic methods: [0003] 1) Solid phase method, JP2000294238 uses ferrous oxalate, diammonium hydrogen phosphate and lithium carbonate as raw materials and calcines under an inert atmosphere. EP1193784 Fe 3 (PO 4 ) 2 and Li 3 PO 4 As a raw material, hydrocarbons are added for s...

Claims

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Application Information

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IPC IPC(8): C01B25/45
CPCY02E60/10
Inventor 唐子龙卢俊彪张中太罗绍华沈万慈
Owner TSINGHUA UNIV
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