Preparation method of lithium iron phosphate/carbon nanotube composite material

A technology of carbon nanotubes and lithium iron phosphate, applied in nanotechnology, nanotechnology, nanotechnology for materials and surface science, etc., can solve the problem of low diffusion coefficient of lithium ions, inability to prevent particle aggregation, uneven size distribution, etc. Problems, to achieve simple process, improve electrochemical performance, increase diffusion coefficient and tap density

Inactive Publication Date: 2012-07-11
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Olivine LiFePO 4 There are three main problems in positive electrode materials: low electrical conductivity, low diffusion coefficient of lithium ions, and low tap density
Existing nanoscale LiFePO 4 There are mainly two kinds of preparation methods: hydrothermal method and solvothermal method. Although the particle size of the prepared granular material can reach the nanometer level, its shape is irregular and the size distribution is not uni

Method used

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  • Preparation method of lithium iron phosphate/carbon nanotube composite material
  • Preparation method of lithium iron phosphate/carbon nanotube composite material
  • Preparation method of lithium iron phosphate/carbon nanotube composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] 1) Mix deionized water and ethylene glycol (V 水 :V 乙二醇=1:1) to make a mixed solvent, and weigh the raw material according to the molar ratio of 1:1:3:3:6:6: 0.01mol FeSO 4 ·7H 2 O, 0.01mol H 3 PO 4 , 0.03mol LiOH·H 2 O, 0.03mol citric acid, 0.06mol polyvinylpyrrolidone K-30 (polyvinylpyrrolidone, PVP) or polyethylene glycol-400 low molecular weight (polyethylene glycol, PEG-400) and 0.06mol single-walled carbon nanotubes (CNT);

[0036] 2) Take 60ml of the mixed solvent prepared in step 1), first add LiOH·H 2 O and H 3 PO 4 Mix and stir with the mixed solvent in a beaker to prepare a solution with a total molar concentration of 0.67mol / L, and then place the beaker in an ultrasonic cleaner to ultrasonically disperse and dissolve the solution;

[0037] 3) Add FeSO to the solution obtained in step 2) while stirring 4 ·7H 2 O and citric acid are then ultrasonically dispersed and dissolved to obtain a mixed solution with a total molar concentration of 1.33mol / L;

...

Embodiment 2

[0044] Embodiment 2: deionized water and ethylene glycol (V 水 :V 乙二醇 =1:1) to prepare a mixed solvent, and weigh the raw material according to the molar ratio of 1:1:3:5 / 3:10 / 3:10 / 3: 0.01mol FeSO 4 ·7H 2 O, 0.01mol H 3 PO 4 , 0.03mol LiOH·H 2 O, 0.0167mol citric acid, 0.033mol polyvinylpyrrolidone K-30 (polyvinylpyrrolidone, PVP) or polyethylene glycol-400 low molecular weight (polyethylene glycol, PEG-400) and 0.033mol single-wall carbon nanotube (CNT); step The concentration of the lithium source and phosphate source in 2) is 0.5 mol / L, the concentration of the solution after adding the ferrous source and reducing agent in step 3) is 1.5 mol / L, and the amount of sucrose in step 7) is 1% of the precursor The mass percentage is 37%.

[0045] Other steps of material synthesis and preparation, electrode fabrication, battery assembly, characterization techniques, and test conditions are consistent with those in Example 1.

[0046] XRD analysis showed that LiFePO 4 It is a...

Embodiment 3

[0047] Embodiment 3: deionized water and ethylene glycol (V 水 :V 乙二醇 =1:1) to prepare a mixed solvent, and weigh the raw material according to the molar ratio of 1:1:3:1:2:2: 0.01mol FeSO 4 ·7H 2 O, 0.01mol H 3 PO 4 , 0.03mol LiOH·H 2 O, 0.01mol citric acid, 0.02mol polyvinylpyrrolidone K-30 (polyvinylpyrrolidone, PVP) or polyethylene glycol-400 low molecular weight (polyethylene glycol, PEG-400) and 0.02mol single-wall carbon nanotube (CNT); step The concentration of the lithium source and the phosphate source in 2) is 1.5 mol / L, the concentration of the solution after adding the ferrous source and the reducing agent in step 3) is 1 mol / L, and the amount of sucrose added in step 7) is the weight of the precursor The percentage is 40%.

[0048] Other steps of material synthesis and preparation, electrode fabrication, battery assembly, characterization techniques, and test conditions are consistent with those in Example 1.

[0049] XRD analysis showed that LiFePO 4 It i...

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Abstract

The invention provides a preparation method of a lithium iron phosphate/carbon nanotube composite material. The preparation method comprises the steps of: dissolving a lithium source and a phosphate source in a mixed liquor agent prepared from alcohol and water to prepare a reaction solution, then adding a ferrous source and a reducing agent, then adding a surfactant, finally adding carbon nanotubes, reacting for 6-8h in a polytetrafluoroethylene high-pressure reaction kettle at 160-200 DEG C to obtain a precursor, calcining the obtained precursor at 600-800 DEG C under the protection of inert gas to prepare the lithium iron phosphate/carbon nanotube composite material with favorable performance. The lithium iron phosphate prepared according to the invention has the advantages of high purity, small grain size, regular shapes and the like, and the carbon nanotubes are embedded into the interiors or cladded onto the surfaces of lithium iron phosphate particles to play a role of electric conductive network, so that the composite material achieves an excellent electrochemical property and is an ideal cathode material for preparing the lithium ion battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to a preparation method of lithium iron phosphate / carbon nanotubes, a positive electrode material of lithium ion batteries. Background technique [0002] In the past two decades, due to the high specific capacity and good safety performance of lithium-ion batteries, a technological revolution in portable electronic products has been set off. As the new energy vehicle industry has become one of the country's seven strategic emerging industries, batteries, as the source of power, have become a key bottleneck in the development of the new energy vehicle industry. The rapid development of lithium-ion batteries provides technical support for solving this bottleneck. At the same time, lithium-ion batteries are also the most effective way to store and use sustainable new energy. At present, the common cathode materials for lithium-ion batteries mostly use LiCoO 2 , LiNi 0.8...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/62B82Y30/00B82Y40/00
CPCY02E60/12Y02E60/10
Inventor 娄永兵朱林
Owner SOUTHEAST UNIV
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