Method for preparing lithium ferrous phosphate

A technology of lithium ferrous phosphate and hydrated iron phosphate, applied in the field of material science, can solve the problems of difficult mixing of reactants, poor electrochemical performance, irregular morphology, etc., achieve good electrochemical performance, improve electrical conductivity, cycle time short effect

Active Publication Date: 2011-06-29
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the synthesis process of the high-temperature solid-phase method is simple, the reactants are not easy to mix uniformly, the reaction time is long, and multiple sintering is required. rule, the electrochemical performance is also poor

Method used

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  • Method for preparing lithium ferrous phosphate
  • Method for preparing lithium ferrous phosphate
  • Method for preparing lithium ferrous phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Get 620g hydrated iron phosphate FePO 4 .2H 2 O was dehydrated in an air atmosphere at a heating rate of 4°C / min to 550°C for 10 hours to obtain anhydrous iron phosphate powder. Weigh 110g of sucrose, 500g of anhydrous ferric phosphate and 125g of lithium carbonate (Li:C:Fe=1.02:1.16:1), add 1000ml of water, and mix in a basket ball mill for 2 hours at a high speed at a ball milling speed of 1200rpm to form a uniform slurry Material (solid content of slurry 38%). The average particle diameter D50 of suspended solid particles in the slurry is 0.5 microns. The obtained slurry is dried with an air-flow spray dryer, adopting a co-current drying method, and the atomization device adopts a double-flow nozzle. Feed with a peristaltic pump at a feed rate of 15ml / min. The gas flow rate of the nozzle is controlled by the pressure of compressed air, atomization is generated at about 0.4MPa, the air inlet temperature is controlled to be 300°C, the outlet temperature is 120°C, a...

Embodiment 2

[0031] Get 620g hydrated iron phosphate FePO 4 .2H 2 O was dehydrated by roasting at 300°C for 12 hours in an air atmosphere to obtain anhydrous iron phosphate powder. Take by weighing 120g glucose, 500g anhydrous ferric phosphate and 145g lithium hydroxide (LiOH.H 2 O) (Li: C: Fe=1.04: 1.2: 1), add 1500ml of water, mix 2hr in the high-speed ball mill in the basket ball mill, 2000rpm of ball milling speed, form uniform slurry (slurry solid content 34%), slurry The average particle diameter D50 of suspended solid particles in the medium is 0.3 microns. The obtained slurry is dried with an air-flow spray dryer, adopting a co-current drying method, and the atomization device adopts a double-flow nozzle. Feed with a peristaltic pump at a feed rate of 10ml / min. The gas flow rate of the nozzle is controlled by the pressure of the compressed air, atomization is generated at about 0.4MPa, the air inlet temperature is controlled at 260°C, the outlet temperature is 110°C, and the ou...

Embodiment 3

[0034] Get 620g hydrated iron phosphate FePO 4 .2H 2 O was dehydrated by roasting at 450°C for 6 hours in an air atmosphere to obtain anhydrous iron phosphate powder. Take by weighing 100g pentaerythritol, 500g anhydrous iron phosphate and 350g lithium acetate (CH 3 COOLi.2H 2O) (Li: C: Fe=1.03: 1.11: 1), add 1000ml of water, mix 2hr in the high-speed ball mill in the basket ball mill, the ball mill rotating speed 1500rpm, form uniform slurry (solid content of slurry 49%), slurry The average particle diameter D50 of suspended solid particles in the medium is 0.6 microns. The obtained slurry is dried with an air-flow spray dryer, adopting a co-current drying method, and the atomization device adopts a double-flow nozzle. Feed with a peristaltic pump at a feed rate of 10ml / min. The gas flow rate of the nozzle is controlled by the pressure of the compressed air, atomization is generated at about 0.4MPa, the air inlet temperature is controlled to be 300°C, the outlet temperat...

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Abstract

The invention discloses a method for preparing a lithium ferrous phosphate material by a spray drying-carbothermic reduction method. The method comprises the following steps: (1) roasting and dewatering iron phosphate hydrate for 2-12 hours at 200-600 DEG C to obtain anhydrous iron phosphate powder; (2) weighing the anhydrous iron phosphate, lithium source compounds and carbon source compounds according to a stoichiometric proportion, adding pure water and ball milling at high speed to uniformly mix so as to obtain a slurry with the solid content of 20-50 percent, wherein the mean grain size D50 of suspended solid particles in the slurry is 0.1-1 micrometer; (3) spraying and drying the obtained slurry to obtain a mixed powder precursor, and carrying out heat treatment and carbothermic reduction on the precursor at 700-900 DEG C under the protection of inert gas to obtain a lithium ferrous phosphate powder material. The lithium ferrous phosphate material prepared by the method has uniform constituents and good batch stability. The 2C discharge specific capacity of the lithium ferrous phosphate material at room temperature is larger than 130mAh / g, thus the lithium ferrous phosphate material has great application value in the field of power type lithium ion batteries.

Description

technical field [0001] The invention relates to a method for preparing lithium iron phosphate material by a spray drying-carbothermal reduction method, which belongs to the technical field of material science. Background technique [0002] With the rapid development of the electronics and information industries, a large number of portable electronic products such as mobile communication equipment, notebook computers, and digital products have been widely used, making society put forward higher requirements for the performance of batteries, especially rechargeable secondary batteries: Higher capacity, smaller size, lighter weight and longer service life. Lithium-ion batteries have become a research hotspot due to their high energy density, high operating voltage, good load characteristics, fast charging speed, safety and pollution-free, and no memory effect. [0003] Cathode materials are an important part of lithium-ion batteries, mainly layered LiCoO 2 , LiNiO 2 、LiNi 0...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58C01B25/45
CPCY02E60/12Y02E60/10
Inventor 任建国蒲薇华武玉玲何向明王莉李建军高剑姜长印万春荣
Owner TSINGHUA UNIV
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