Lithium/carbon pyrophosphate coated lithium iron phosphate composite and preparation method thereof

A technology of carbon-coated lithium iron phosphate and composite materials, which is applied to electrical components, battery electrodes, circuits, etc., can solve problems affecting battery processing, etc., to improve electrical conductivity and ion conductivity, improve power performance, and uniform particle size Effect

Active Publication Date: 2013-12-11
QINGHAI TAIFENG XIANXING LITHIUM ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the excess of Li in the sintering process, easily in LiFePO 4 Li produced on the surface 2 O, LiOH, and Li 2 CO 3

Method used

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  • Lithium/carbon pyrophosphate coated lithium iron phosphate composite and preparation method thereof
  • Lithium/carbon pyrophosphate coated lithium iron phosphate composite and preparation method thereof
  • Lithium/carbon pyrophosphate coated lithium iron phosphate composite and preparation method thereof

Examples

Experimental program
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Example Embodiment

[0028] Example 1:

[0029]Weigh 111.16g of lithium carbonate, 493.57g of ferrous oxalate, and 310.80g of ammonium dihydrogen phosphate according to the molar ratio of lithium, iron, and phosphorus to 1:0.9:0.9 for the first mixing. Add ammonium dihydrogen phosphate, lithium carbonate, and ferrous oxalate to a 10L blue grinder with 3kg of ethanol in turn every half hour, at a speed of 1500r / min, and grind for 2 hours until the particle size reaches D50<4um. The material is introduced into the sand mill, and after the sand grinding particle size reaches 300-400nm, the slurry is poured into a tray and placed in a fume hood for static drying, and then crushed after complete drying. Under a nitrogen atmosphere, the crushed material was placed in a tube furnace for the first sintering at a sintering temperature of 400°C and kept at a constant temperature for 2 hours. Add 70g of the pre-calcined product to a 2L blue grinder containing 1000ml of ethanol for the second mixing at a spe...

Example Embodiment

[0032] Experimental example 2

[0033] Lithium hydroxide, iron oxide, and diammonium hydrogen phosphate were weighed and mixed for the first time according to the molar ratio of lithium, iron, and phosphorus elements being 1:0.8:0.0.8. Add diammonium hydrogen phosphate, lithium hydroxide, and iron oxide to a 10L blue grinder filled with 3kg of methanol in sequence every half hour, at a speed of 1500r / min, and grind for 2 hours until the particle size reaches D50<4um. The material is introduced into the sand mill, and after the sand grinding particle size reaches 300-400nm, the slurry is poured into a tray and placed in a fume hood for static drying, and then crushed after complete drying. Under a helium atmosphere, the crushed material was placed in a tube furnace for the first sintering at a temperature of 600 degrees and kept at a constant temperature for 2 hours. Add 70g of the pre-calcined product to a 2L blue grinder containing 1000ml of ethanol for the second mixing at ...

Example Embodiment

[0034] Experimental example 3

[0035] Weigh lithium acetate, iron citrate, and phosphoric acid for the first mixing according to the molar ratio of lithium, iron, and phosphorus elements being 1:0.94:0.94. Add phosphoric acid, lithium acetate, and ferric citrate to a 10L blue grinder filled with 3kg of acetone in turn every half hour at a speed of 1500r / min, and grind for 2 hours until the particle size reaches D50<4um, then import the slurry into the sand In the mill, after the sand grinding particle size reaches 300-400nm, pour the slurry into a tray and place it in a fume hood for static drying, and then crush it after drying completely. Under an argon atmosphere, the crushed material was placed in a tube furnace for the first sintering at a sintering temperature of 400°C and kept at a constant temperature for 10 hours. Add 70g of the pre-calcined product to a 2L blue grinder containing 1000ml of N-methyl-2-pyrrolidone for the second mixing at a speed of 1000r / min. After ...

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Abstract

The invention discloses a lithium/carbon pyrophosphate coated lithium iron phosphate composite and a preparation method thereof. The preparation method comprises the steps of preparing Li2O coated lithium iron phosphate, and obtaining the lithium/carbon pyrophosphate coated lithium iron phosphate composite through in-situ solid phase reaction of excessive LiO2 and excessive phosphor salt. Smooth-faced lithium iron phosphate is prepared by the fluxing action of Li2O in a first sintering process, a certain phosphorus source and a carbon source are added in a second mixing process, the added phosphorus source reacts with excessive Li2O in a second sintering process to produce lithium pyrophosphate, and finally the lithium/carbon pyrophosphate coated lithium iron/carbon phosphate composite is prepared. Lithium pyrophosphate is a vitreous fast ionic conductor, and can greatly improve power performances of lithium iron phosphate.

Description

technical field [0001] The invention belongs to the technical field of cathode materials for lithium ion batteries, and in particular relates to a lithium pyrophosphate / carbon-coated lithium iron phosphate composite material and a preparation method thereof. Background technique [0002] Since the advent of lithium-ion batteries in the early 1990s, they have been widely favored by people due to their high energy density, stable discharge voltage, and long working life. The research and application of lithium-ion batteries have also been paid more and more attention. As an important part of lithium-ion batteries, cathode materials play a key role in battery safety, voltage, and capacity, and directly determine the performance of lithium-ion batteries. At present, the widely studied cathode materials for lithium-ion batteries are mainly some transition metal oxides, including LiCoO with a hexagonal layered structure. 2 , LiMnO 2 and spinel-structured LiMn 2 o 4 ; and some ...

Claims

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Application Information

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IPC IPC(8): H01M4/58
CPCY02E60/10
Inventor 黄长靓周恒辉张卫东王丹唐春霞岳艳花
Owner QINGHAI TAIFENG XIANXING LITHIUM ENERGY TECH CO LTD
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