Boron containing lithium iron phosphate/carbon composite material and preparation thereof

A carbon composite material, lithium iron phosphate technology, applied in chemical instruments and methods, electrode manufacturing, chemical/physical processes, etc. damage and other problems, to achieve the effect of simple mixing technology, good comprehensive performance and high tap density

Active Publication Date: 2009-02-11
杭州金马新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a boron-containing lithium iron phosphate/carbon composite material and its preparation method, which mainly solves the difficulties in the ultrafine pulverization, uniform dispersion and mixing of raw materials in the prior art, and the coated carbon layer The bonding strength with the surface of lithium iron phosphate is not high enough, the crushing and grading process will damag

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Embodiment 1: a kind of boron-containing lithium iron phosphate / carbon composite material of this example, its molecular formula is:

[0026] LiFePO 4 3.769×10 -2 B 2 o 3 / C

[0027] Its preparation method steps are:

[0028] a. In the ball mill jar that 820g dehydrated alcohol is housed, add 3.540g non-ionic polymer borate ester surfactant PBE (average weight relative molecular weight Mw=28400), fully stir, then add 0.5 mole Li respectively 2 CO 3 36.945g, 1.0 mole FeC 2 o 4 2H 2 O 179.900g, 1.0 mol NH 4 h 2 PO 4 115.000g, 19.500g glucose and 2.624g B 2 o 3 , mix; add 5mm zirconia balls to the mixed solid powder, the mass ratio of solid powder to zirconia balls is 1:8, stir and ball mill for 7 hours at a speed of 300 rpm;

[0029] b'. After evaporating ethanol to dryness, the solid powder produced in step a is sintered at 400° C. under the protection of a mixed gas of high-purity nitrogen with a volume ratio of 92:8. The heat treatment procedure is: 3 ho...

Embodiment 2

[0033] Embodiment 2: a kind of boron-containing lithium iron phosphate / carbon composite material of this example, its molecular formula is:

[0034] LiFePO 4 0.070 LiBO 2 / C

[0035] Its preparation method steps are:

[0036] a. In the ball mill jar that 820g dehydrated ethanol is housed, add 3.583g non-ionic polymer borate ester surfactant PBE (weight-average relative molecular weight Mw=28400), fully stir, then add 0.535 moles of Li respectively 2 CO 3 39.531g, 1.0 mole FeC 2 o 4 2H 2 O 179.900g, 1.0 mol NH 4 h 2 PO 4 115.000g, 19.500g glucose and 0.070 mole H 3 BO 3 4.327g, mixed;

[0037] All the other steps are the same as in Example 1.

[0038] According to the stoichiometric ratio, the obtained boron-containing lithium iron phosphate carbon composite material contains LiBO 2 0.070 mol, ie ζ = 0.070. The laser particle size analyzer measured that the average particle size of the solid particles in the slurry after ball milling in step b for 7 hours was...

Embodiment 3

[0039] Embodiment 3: a kind of boron-containing lithium iron phosphate / carbon composite material of this example, its molecular formula is:

[0040] LiFePO 4 0.25B 2 o 3 / C

[0041] Its preparation method steps are:

[0042] a. In the ball mill jar that 820g dehydrated alcohol is housed, add 3.688g non-ionic polymer borate ester surfactant PBE (average weight relative molecular weight Mw=28400), fully stir, then add 0.5 mole of Li respectively 2 CO 3 36.945g, 1.0 mole FeC 2 o 4 2H 2 O 179.900g, 1.0 mol NH 4 h 2 PO 4 115.000g, 19.500g glucose and 17.405g B 2 o 3 , to mix;

[0043] All the other steps are the same as in Example 1.

[0044] According to the stoichiometric ratio, the obtained boron-containing lithium iron phosphate carbon composite material contains B 2 o 3 0.25 mol, ie ξ=0.25.

[0045] The carbon content in the boron-containing lithium iron phosphate / carbon composite material measured by the HCS-140 high-frequency infrared carbon-sulfur analyze...

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Abstract

The invention relates to an anode material for secondary lithium batteries, in particular to a lithium iron phosphate/carbon composite material containing boron, and the preparation method thereof, and mainly solves the technical problems of lower bonding strength of coating the carbon layer and the lithium iron phosphate surface, relatively low product tap density, rapid growth of the grain size, non-uniform and non-centralized distribution, and poor uniformity in the electrical property of lithium iron phosphate and the product quality, etc., in the prior art. The chemical formula of the lithium iron phosphate/carbon composite material is Li1-xMxFe1-yNyP1-zSizO4.XiB2O3/C or Li1-xMxFe1-yNyP1-zSizO4.ZetaLiBO2/C. The preparation method comprises the following steps: adding a boric acid ester surface active agent or/and a fluxing agent to a ball milling tank filled with a solvent; stirring uniformly; further adding iron-source compounds, lithium-source compounds, phosphorus-source compounds and carbon-coated carbon source respectively and mixing; evaporating the solvent to dryness and sintering the obtained solid powder under the protection of inert gases; cooling and taking out; and pulverizing, grading and obtaining the finished product.

Description

technical field [0001] The invention relates to a secondary lithium battery cathode material, in particular to a boron-containing lithium iron phosphate / carbon composite material and a preparation method thereof. Background technique [0002] Since Sony first launched lithium-ion batteries on the market in the early 1990s, lithium-ion batteries have been known for their high operating voltage (more than 3 volts relative to metal lithium), high specific energy, low self-discharge rate, no memory effect and excellent The cycle stability and other advantages have become the preferred power source for small electronic devices such as mobile communications, notebook computers and cameras (cameras). At present, the application range of lithium-ion batteries has been expanded to large-capacity, high-power power supplies such as electric tools, miner's lamps, electric bicycles, electric vehicles, hybrid electric vehicles, satellites and weaponry, and has a very huge market prospect....

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/48H01M4/04B01J19/00
CPCY02E60/10
Inventor 龚金保余爱水戴康泉王伯良王叶滔陆越兴卢宇驰萧张兴
Owner 杭州金马新能源科技有限公司
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