Lithium iron phosphate electrode material having three-dimensional hierarchical structure, and preparation method thereof

A hierarchical structure, lithium iron phosphate technology, applied in battery electrodes, structural parts, chemical instruments and methods, etc., can solve the problems of limited material application and difficult to obtain

Inactive Publication Date: 2014-07-30
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this material has outstanding advantages such as high specific capacity, high stability and high cycle life as a power battery, many researchers have devoted themselves to LiFePO 4

Method used

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  • Lithium iron phosphate electrode material having three-dimensional hierarchical structure, and preparation method thereof
  • Lithium iron phosphate electrode material having three-dimensional hierarchical structure, and preparation method thereof
  • Lithium iron phosphate electrode material having three-dimensional hierarchical structure, and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] 2 g polyvinylpyrrolidone K 30 and 0.98 g H 3 PO 4 Add in 15ml ethylene glycol solvent, magnetic stirring is even; Then the Fe(NO of 4.04 grams 3 ) 3 9H 2 O and 0.64 g Li 2 SO 4 ·H 2 O is dispersed in 10ml and 15ml of ethylene glycol, and magnetically stirred evenly; finally, the three solutions are quickly mixed and stirred evenly (at this time, the ion concentrations of phosphorus source compound, iron source compound and lithium source compound are all 0.25mol / L, and the number of moles The ratio is 1:1:1) into a 100ml reactor and reacted at 180°C for 24 hours. The resulting product was washed with absolute ethanol three times and then dried in vacuum at 80°C for 12 hours. Calcined for 10 hours under ambient conditions to obtain lithium iron phosphate with hierarchical structure. A high-magnification scanning electron microscope can clearly observe that the bird's nest-shaped lithium iron phosphate grains are assembled from smaller nanosheets ( figure 1 ), f...

Embodiment 2

[0049] 2 g polyvinylpyrrolidone K 90 and 0.98 g H 3 PO 4 Add 15ml of ethylene glycol and ethanol mixed solvent (volume ratio is 1:1), magnetically stir evenly; then respectively add 4.04g of Fe(NO 3 ) 3 9H 2 O and 0.64 g Li 2 SO 4 ·H 2 O is dispersed in 10ml and 15ml of mixed solvents, and magnetically stirred evenly; finally, the three solutions are quickly mixed and stirred evenly (at this time, the ion concentrations of the phosphorus source compound, the iron source compound and the lithium source compound are all 0.25mol / L, and the molar ratio 1:1:1) into a 100ml reactor and reacted at 180°C for 24 hours, the resulting product was washed 3 times with absolute ethanol and then vacuum-dried at 100°C for 12 hours, and then placed in a vacuum tube furnace at 700°C under Ar gas environment Calcined for 10 hours at the bottom to obtain lithium iron phosphate with hierarchical structure. The high-magnification scanning electron microscope can clearly observe that the flo...

Embodiment 3

[0051] 1 gram of cetyltrimethylammonium bromide and 2.03 grams of (NH 4 ) 3 PO 4 ·3H 2 O was added to 25ml deionized water and ethanol mixed solvent (the volume ratio of deionized water and ethanol was 1:2), and magnetically stirred evenly; then 2.5 grams of FeAc 2 4H 2 O and 1.69 grams of LiCl were dispersed in 15ml and 20ml mixed solvents, and magnetically stirred evenly; finally, the three solutions were mixed and stirred evenly (at this time, the ion concentrations of the phosphorus source compound, the iron source compound and the lithium source compound were 0.17, 0.17, 0.67mol / L, the molar ratio is 1:1:4) into a 100ml reactor and reacted at 200°C for 36 hours. Vacuum dried for 18 hours, and then in a vacuum tube furnace at 600 °C, N 2 Calcined under air environment for 8 hours to obtain lithium iron phosphate with hierarchical structure. The resulting shuttle-like lithium iron phosphate grains are assembled from finer nanorods to form a hierarchical structure. Th...

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Abstract

The present invention relates to a lithium iron phosphate electrode material having a three-dimensional hierarchical structure, and a preparation method thereof. The preparation method comprises: 1) sequentially adding a surfactant and a phosphorus source compound to a solvent, and uniformly stirring for use; 2) dispersing an iron source compound in a solvent, and uniformly stirring for use; 3) dispersing a lithium source compound in a solvent, and uniformly stirring for use; 4) mixing and stirring the solutions or suspensions of the phosphorus source compound, the iron source compound and the lithium source compound, and loading into a reaction kettle; 5) carrying out a reaction under a hydrothermal or solvothermal condition, and washing and drying the obtained product to obtain lithium iron phosphate with various hierarchical structures; and 6) calcining to obtain the hierarchical structure lithium iron phosphate material having high crystallinity. According to the present invention, the preparation method is the wet chemical method for preparing the lithium ion battery positive electrode material lithium iron phosphate (LiFePO4) by adopting the precursor directly obtained through the hydrothermal or solvothermal reaction, and the surface activity structure-oriented method is adopted to design and construct the electrode material having high specific surface area and excellent electrochemical property.

Description

technical field [0001] The invention relates to a three-dimensional hierarchical lithium iron phosphate electrode material with excellent electrochemical performance and a preparation method thereof. Background technique [0002] At present, the most widely used anode materials for lithium-ion batteries are mainly transition metal oxides of lithium, such as lithium cobalt oxide (LiCoO 2 ), lithium nickelate (LiNiO 2 ) and spinel lithium manganate (LiMn 2 o 4 )Wait. Currently mass-produced lithium-ion batteries mainly use LiCoO 2 As a positive electrode material, its energy density is high and its performance is stable, but because cobalt is a rare resource, lithium cobalt oxide is expensive, and its safety is not good, and it is easy to cause combustion or explosion accidents, so it is used in lithium-ion batteries, especially power lithium batteries. Applications in ion batteries are limited. LiNiO 2 It has the advantages of high specific capacity and abundant resour...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/1397
CPCC01B25/45H01M4/5825H01M10/0525Y02E60/10
Inventor 木士春张伟杨金龙康晓春胡林
Owner WUHAN UNIV OF TECH
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