Method for preparing carbon-coated lithium iron phosphate anode material of lithium ion battery

A carbon-coated lithium iron phosphate and lithium-ion battery technology, which is applied to battery electrodes, circuits, electrical components, etc., can solve the problems of reducing the content of active materials and reducing the overall capacity, and achieves excellent cycle performance and excellent super-large rate performance , the effect of excellent size magnification performance

Inactive Publication Date: 2011-04-20
SOUTH CHINA UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But this is also a disadvantage, because in order to achieve a good complexing effect, a certain amount of complexing agent must be used, and this amount will often make the product contain too much carbon, thereby reducing the content of active substances and reducing the overall capacity

Method used

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  • Method for preparing carbon-coated lithium iron phosphate anode material of lithium ion battery
  • Method for preparing carbon-coated lithium iron phosphate anode material of lithium ion battery
  • Method for preparing carbon-coated lithium iron phosphate anode material of lithium ion battery

Examples

Experimental program
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Effect test

Embodiment 1

[0035] 1.039g LiH 2 PO 4 , 4.041gFe(NO 3 ) 3 9H 2 O, 6.3g of citric acid monohydrate, 1.6g of ethylene glycol, and 3.2g of ammonium nitrate were dissolved in water to form a sol, heated and evaporated to dryness to form a gel, and then the gel was ignited and burned to obtain an intermediate. Figure 1-Figure 3 It is the SEM picture of the intermediate body, it can be seen that the intermediate body is highly porous sponge, its particle size is about 10nm, and the diameter of the hole is about 500nm. After the intermediate was mixed with 0.4g glucose and 8g acetone ball milled for 8h, the 2 , and calcined at 700°C for 8 hours to obtain carbon-coated lithium iron phosphate. Figure 4 with Figure 5 The SEM and TEM images of the carbon-coated lithium iron phosphate obtained in this example respectively show that the particle size of the carbon-coated lithium iron phosphate synthesized by the sol-gel-combustion method under this condition is in the range of submicron and mi...

Embodiment 2

[0038] 0.689gLiNO 3 , 4.041gFe(NO 3 ) 3 9H 2 O, 1.15gNH 4 h 2 PO 4 , 4.2g citric acid monohydrate, 9.48g ethylene glycol, and 3.2g ammonium nitrate were dissolved in water to form a sol, heated and evaporated to dryness to form a gel. Then ignite and burn the gel to obtain the intermediate. After the intermediate was mixed with 0.16g sucrose and 3.16g ethanol ball milled for 10h, in H 2 10% N 2 / H 2 Calcined at 850°C for 1 h in a mixed gas to obtain carbon-coated lithium iron phosphate.

Embodiment 3

[0040]1.039g LiH 2 PO 4 , 1.268gFeCl 2 , 21g citric acid monohydrate, 8.0g ethylene glycol, and 12.64g ammonium nitrate were dissolved in water to form a sol, heated and evaporated to dryness to form a gel. Then ignite and burn the gel to obtain the intermediate. After the intermediate was mixed with 0.8g glucose and 31.6g acetone ball milled for 6h, it was mixed in H 2 5% Ar / H 2 Calcined at 550°C for 24 hours in a mixed gas to obtain carbon-coated lithium iron phosphate.

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Abstract

The invention relates to a method for preparing carbon-coated lithium iron phosphate anode material of a lithium ion battery, which is characterized by comprising the following steps of: putting a plurality of compounds including three elements of lithium, ferrum and phosphor and citric acid complexing agent in water to form sol; adding ethylene glycol combustion-supporting agent and ammonium nitrate oxidizing agent for dissolution; heating and boiling down to obtain gel; igniting the gel in air; wet-milling and mixing an intermediate obtained by combustion and a carbon source, finally, calcining in an inert atmosphere or reducing atmosphere to obtain lithium iron phosphate which is carbon-coated lithium iron phosphate since the outer layer of the prepared lithium iron phosphate is coated with a layer of carbon. The method not only utilizes the advantages of a sol-gel method, which mixes materials with even molecular level, but also overcomes the problems of the sol-gel method, in which all parts of the gel have uneven water loss during drying and sever expansion in calcination and the content of product carbon is difficult to control. The carbon-coated lithium iron phosphate prepared by the method has excellent large and small multiplying power performance, especially has excellent super-large multiplying power performance, and excellent cycle performance.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery materials, and in particular relates to a preparation method of carbon-coated lithium ferrous phosphate, a cathode material of lithium ion batteries. Background technique [0002] Due to the wide source of lithium iron phosphate raw materials, low price, no environmental pollution, good thermal stability and structural stability of the material, the prepared battery has outstanding safety performance and long cycle life, making it suitable for various mobile power sources, especially The field of large-scale power supply required by new energy vehicles has great market prospects. This large-scale power supply has high requirements on the price, safety, service life and environmental performance of materials, so that lithium iron phosphate has become the most developed A new generation of cathode materials for lithium-ion batteries with potential applications. [0003] The sol-gel meth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1397H01M4/58
CPCY02E60/122Y02E60/12Y02E60/10
Inventor 王海辉余灵辉张乐
Owner SOUTH CHINA UNIV OF TECH
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