Method for preparing lithium phosphate/carbon-coated lithium iron phosphate composite material

A technology of carbon-coated lithium iron phosphate and composite materials, which is applied to electrical components, electrochemical generators, battery electrodes, etc. Problems such as poor consistency, to achieve the effect of improving electronic conductivity, high conductivity, and high performance

Active Publication Date: 2014-04-16
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

The lithium pyrophosphate-coated lithium phosphate particles prepared by the first method are controllable, but there are also certain shortcomings. The solid-state reaction of the added lithium source and phosphorus source may not all form lithium pyrophosphate during the secondary sintering process, and may Other miscellaneous items will be generated, which may affect the uniform distribution of carbon sources and the electrochemical performance of lithium iron phosphate
However, the second method uses lithium iron phosphate coated with lithium phosphate salt prepared by a one-step method, which has disadvantages such as uncontrollable material particle size, uneven carbon coating, and poor material consistency.

Method used

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  • Method for preparing lithium phosphate/carbon-coated lithium iron phosphate composite material
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  • Method for preparing lithium phosphate/carbon-coated lithium iron phosphate composite material

Examples

Experimental program
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Effect test

Embodiment 1

[0033]Weigh 111.16g of lithium carbonate, 539.41g of ferrous oxalate, and 345.36g of ammonium dihydrogen phosphate according to the molar ratio of lithium, iron, and phosphorus to 1:1:1 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 600°C and kept at a constant temperature for 2 hours. Add 74.14g of the pre-calcined product to a 2L blue grinder containing 1000ml of ethanol for the second mixing at a speed of 1000r / min. After...

experiment example 2

[0037] Lithium hydroxide, iron oxide, and diammonium hydrogen phosphate were weighed for the first mixing according to the molar ratio of lithium, iron, and phosphorus elements being 1:0.9:0.95. 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 sintering temperature of 500 degrees for 2 hours at a constant temperature. Add 71.78g of the pre-calcined product to a 2L blue grinder containing 1000ml of ethanol for the second mixing at a speed of 1000r / min. After grinding f...

experiment example 3

[0040] Weigh lithium acetate, iron citrate, and phosphoric acid for the first mixing according to the molar ratio of lithium, iron, and phosphorus elements being 1:0.97:0.98. 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 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 69.41g 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 grinding for half an hour, calculate ...

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Abstract

The invention discloses a method for preparing a high-performance lithium phosphate/carbon-coated lithium iron phosphate composite material. The method mainly comprises the processes of preparing lithium iron phosphate not subjected to carbon coating and preparing the lithium phosphate/carbon-coated lithium iron phosphate composite material. The method comprises the following steps: performing primary sintering to prepare lithium iron phosphate not subjected to carbon coating, and adding a certain amount of lithium phosphate and carbon source in the secondary mixing process to finally prepare the lithium phosphate/carbon-coated lithium iron phosphate composite material. The lithium phosphate is a fast ionic conductor, the aim of improving the electrical conductivity of lithium iron phosphate is achieved, and the aim of improving the overall performance of the lithium iron phosphate is also achieved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery cathode materials, and in particular relates to a preparation method of a high-performance lithium phosphate / carbon-coated lithium iron phosphate composite material. Background technique [0002] Lithium-ion batteries have been receiving a lot of attention since their introduction in 1991. As an important part of lithium-ion batteries, cathode materials have gradually become the focus of material research. At present, the research on cathode materials mainly focuses on lithium-containing transition metal oxides, such as LiC with hexagonal layered structure. O o 2 , LiMnO 2 and spinel-structured LiMn 2 o 4 and multi-element transition metal oxide LiNi 1-x-y C Ox wxya 2 Wait. [0003] Due to the abundance of iron in the earth's crust and its environmental friendliness, in recent years, more and more people have studied iron-containing lithium salts to replace the current cathode...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCH01M4/366H01M4/5825H01M4/625H01M10/0525Y02E60/10
Inventor 黄长靓张卫东周恒辉唐春霞岳艳花王丹
Owner QINGHAI TAIFENG XIANXING LITHIUM ENERGY TECH CO LTD
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