Lithium iron phosphate-carbon nanotube composite material, preparation method, and application thereof

A technology of lithium iron phosphate and carbon nanotubes, which is applied in the preparation of lithium iron phosphate-carbon nanotube composite materials, in the field of lithium iron phosphate-carbon nanotube composite materials, to achieve the effect of improving dispersion and good crystal form

Active Publication Date: 2012-04-25
HUBEI RT ADVANCED MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved in the present invention is to provide a lithium iron phosphate-carbon nanotube composite material to solve the problem of LiFePO 4 The problem of the effective introduction of carbon nanotubes in the material, the preparation of a uniformly distributed carbon nanotube conductive network, the carbon layer and CNTs of the composite material are well crystallized, the overall carbon content is low, and the conductivity and specific capacity of the composite material are effectively improved, thereby greatly improving the material. Rate characteristics of composite materials

Method used

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  • Lithium iron phosphate-carbon nanotube composite material, preparation method, and application thereof
  • Lithium iron phosphate-carbon nanotube composite material, preparation method, and application thereof
  • Lithium iron phosphate-carbon nanotube composite material, preparation method, and application thereof

Examples

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Embodiment 1

[0047] with Fe 3 (PO 4 ) 2 ·8H 2 O. Li 3 PO 4 As a raw material, with absolute ethanol as a dispersant, the ratio of lithium source, iron source, and phosphorus source is weighed according to Li:Fe:P=1:1:1 (molar ratio), and the Fe 3 (PO 4 ) 2 ·8H 2 O 5kg, weighing Li 3 PO 4 1.2kg, adding 6L of absolute ethanol, mechanical ball milling for 8 hours and then drying to obtain the precursor powder. The catalyst components are 1g of nickel sulfate, 0.5g of ammonium heptamolybdate, and 10g of magnesium sulfate. The solution is prepared with 3kg of propanol, and the precursor powder is added and stirred evenly. The pH is adjusted to 8 with ammonia water. 30% slurry. Adjust the parameters of the spraying equipment, spray the above slurry into the rotary furnace at a uniform speed, the inert atmosphere is 3000 SCCM positive high-purity nitrogen, and the furnace temperature is stabilized at 700°C and kept warm. The feeding time lasts for 20 minutes. After the end, the high-...

Embodiment 2

[0050] FePO 4 2H 2 O. Li 2 CO 3 As the main raw material, weigh the raw material according to the mol ratio of 2:1, FePO 4 2H 2 O3.7kg, Li 2 CO 3 0.7kg, a total of 4kg, the dispersant is acetone 3L, mechanical ball milling for 3 hours and then drying to obtain the precursor powder. The catalyst is 2g of iron nitrate, 20g of magnesium nitrate, and 2kg of absolute ethanol, which are mixed with the precursor powder and fed with ammonia gas to adjust the pH value to 8 to make a slurry. Adjust the parameters of the spray equipment, spray the above slurry into the rotary furnace at a uniform speed, the inert atmosphere is 3000 sccm positive high-purity argon, and the furnace temperature is stable at 800°C. The feeding time lasts for 10 minutes. After the end, the high-pressure nitrogen flow will bring the powder into the rear section of the reaction furnace for deposition. After the nitrogen gas is kept at normal pressure for 6 hours, it is cooled and sampled to obtain LiFeP...

Embodiment 3

[0052] Weigh 2LiOH·H at a ratio of 1:2mol 2 O, FePO 4 2H 2 O is 2kg in total, using 2L of isopropanol as a dispersant to mix evenly, then blending with a solution of 2g of magnesium nitrate, 1g of nickel nitrate, and 0.4g of ammonium heptamolybdate dissolved in 50g of absolute ethanol, and adjusting the pH value to the catalyst group by using ammonia water After the sub-precipitation is complete, continue to add 8 kg of absolute ethanol to adjust the overall solid content of the slurry to 20%, and stir at a high speed to prepare a stable precursor slurry. Adjust the parameters of the spray equipment, spray the above slurry into the rotary furnace at a uniform speed, and the inert atmosphere is 2000 sccm forward high-purity argon. The feed reaction time was controlled to 12 minutes, and the floating CVD temperature was 700°C for the reaction; the composite precursor was kept at 730°C for 2 hours in the sintering section, and then cooled and sampled to obtain LFP-CNTs with a c...

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Abstract

The present invention discloses a lithium iron phosphate-carbon nanotube (LiFePO4-CNTs) composite material. The composite material comprises LiFePO4 particles, a nano-carbon layer and CNTs, wherein the nano-carbon layer is positioned outside the LiFePO4 particles, and the CNTs grow in the nano-carbon layer in an in situ growth manner by a chemical vapor deposition (CVD) process. In addition, the present invention further discloses a preparation method for the composite material. The method comprises: uniformly mixing and coating the prepared LiFePO4 precursor powder, a catalyst and liquid carbon source to prepare into the slurry; adopting a spraying feeding device to convey the slurry to a high-temperature reaction furnace to form a floating CVD process; carrying out heat insulation calcination for the resulting mixture so as to complete the treatments of granulation of the LiFePO4 precursor, in situ growth and coating of the CNTs and synthesis sintering of the LiFePO4 in one step, such that the uniform nano-carbon layer and the CNTs are formed on the surfaces of the LiFePO4 particles. In addition, the present invention further discloses an application of the composite material in battery preparation. According to the composite material of the present invention, the nano-carbon layer and the CNTs have good crystallization, the total carbon content is low, the electrical conductivity and the specific capacity are high so as to substantially increase the rate performance.

Description

technical field [0001] The invention belongs to the field of composite cathode materials for power batteries, and relates to a lithium iron phosphate-carbon nanotube composite material (LiFePO 4 -CNTs); In addition, the present invention also relates to the preparation method and application of the lithium iron phosphate-carbon nanotube composite material. Background technique [0002] Lithium iron phosphate (LiFePO 4 , referred to as LFP) as an emerging power battery cathode material is inexpensive and has broad application prospects. The conductivity of pure-phase lithium iron phosphate is very low, and it needs to be improved to have practical application value. Nanfang Chemical and A123 have disclosed methods for synthesizing one-dimensional nanocrystalline grains to improve their conductivity (CN 101155756A, CN101427402A, CN101361210A); and Nanfang Chemical has a patent for improving the performance of lithium iron phosphate by carbon layer coating (US7344659, US6855...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/1397
CPCY02E60/122Y02E60/10
Inventor 王科伟田强陈小刚安静张军
Owner HUBEI RT ADVANCED MATERIALS CO LTD
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