Lithium iron phosphate composite electrode with metal oxide coating layer on surface

A technology of oxide coating and lithium iron phosphate, which is applied in electrode manufacturing, battery electrodes, circuits, etc., can solve problems affecting the structural stability of lithium iron phosphate, increase the difficulty of process processing, and increase the hygroscopicity of materials, so as to achieve heat suppression Effects of runaway reaction, reduction of dissolution, and inhibition of corrosion

Inactive Publication Date: 2018-01-26
SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Doping and modification can significantly improve the electronic conductivity of lithium iron phosphate and improve the high-rate charging performance of the material, but the surface coating process is generally more complicated and will significantly reduce the tap density of the material, and the doping of metal ions is bound to It will affect the structural s

Method used

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  • Lithium iron phosphate composite electrode with metal oxide coating layer on surface
  • Lithium iron phosphate composite electrode with metal oxide coating layer on surface
  • Lithium iron phosphate composite electrode with metal oxide coating layer on surface

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0025] Example 1

[0026] The lithium iron phosphate, acetylene black and polyvinylidene fluoride (PVDF) are uniformly mixed into a slurry, and the slurry is uniformly coated on the aluminum current collector with an automatic coating machine, dried, and rolled to prepare a lithium iron phosphate electrode sheet. The mass ratio of lithium iron phosphate: acetylene black: PVDF is 85:7:8, and the thickness of the rolled lithium iron phosphate pole piece is about 55 μm (with current collector).

[0027] Add 10g Al with particle size D50=300nm to 100g deionized water 2 O 3 Granules and 1g polyvinylpyrrolidone (PVP), mix well, stir and disperse with a planetary ball mill at 400rpm for 2h, then add 12g 50% solid content styrene butadiene rubber (SBR) and 1.5g sodium carboxymethyl cellulose (CMC) (The actual binder content is 7.5g), continue to use a planetary ball mill to continue to disperse for 12 hours at a speed of 400 rpm to obtain evenly dispersed Al 2 O 3 Slurry. The obtained sl...

Example Embodiment

[0033] Example 2

[0034] Add 15g SiO with particle size D50=50nm to 150g deionized water 2 The granules and 1g polyethylene glycol (PEG) are mixed uniformly and dispersed by a planetary ball mill at 400rpm for 24h, and then 60g sodium alginate aqueous solution (sodium alginate: water=1:5wt%) (actual binder content) 10g), continue to use planetary ball mill to stir and disperse at 600rpm for 12h to obtain uniformly dispersed SiO 2 Slurry. The obtained slurry was coated on the surface of the lithium iron phosphate pole piece by spin coating, the spin coating time was 180s, and the thickness of the deposited layer was about 3μm. After natural drying at 60℃, it was dried in a vacuum at 120℃ for 12h to obtain the surface SiO 2 Coated lithium iron phosphate composite electrode, the thickness of the pole piece increased by about 1μm, SiO 2 It accounts for about 0.5% of the weight of the pole piece.

Example Embodiment

[0035] Example 3

[0036] Add 15g Al with particle size D50=500nm into 100g ethanol 2 O 3 After mixing the particles and 1g PVP uniformly, use a planetary ball mill at 200rpm to stir and disperse for 2h, and then add 55g polyvinylidene fluoride (PVDF) acetone solution (PVDF: acetone=1:10wt%) (the actual binder mass is 5g), Continue to use a planetary ball mill to stir and disperse for 12 hours at 300 rpm to obtain evenly dispersed Al 2 O 3 Slurry. After the obtained slurry is heated to 40°C, it is coated on the surface of the lithium iron phosphate pole piece by dip coating. The thickness of the control electrode dip coating is 120μm during dip coating (the thickness of the pole piece increases by about 9.2μm after dip coating and drying, and the mass increases About 4.7%), after natural drying at 60℃, vacuum drying at 120℃ for 12h to obtain surface Al 2 O 3 Coated lithium iron phosphate composite electrode.

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Abstract

The invention relates to a lithium iron phosphate composite electrode with a metal oxide coating layer on a surface. The lithium iron phosphate composite electrode comprises a lithium iron phosphate pole plate and the coating layer, wherein the coating layer is formed by coating a metal oxide, a dispersing agent and a binding agent on the lithium iron phosphate pole plate, the grain size of the metal oxide is 50-500 nanometers, the thickness of the coating layer is 1-10 micrometers, and the mass of the coating layer accounts for 0.1-5% of the total mass of the composite electrode. The invention also relates to a preparation method of the lithium iron phosphate composite electrode. The preparation method comprises the following steps of S1, providing the lithium iron phosphate pole plate; S2, uniformly dispersing the metal oxide and the binding agent in a solvent by the dispersing agent to form paste; and S3, coating the paste on an outer surface of the lithium iron phosphate pole plateand performing drying to obtain the lithium iron phosphate composite electrode. The lithium iron phosphate composite electrode with the metal oxide coating layer on the surface has favorable cycle property and high safety.

Description

technical field [0001] The invention relates to a positive electrode material of a lithium ion battery, in particular to a lithium iron phosphate composite electrode with a metal oxide coating on the surface. Background technique [0002] As a new type of energy storage device, lithium-ion batteries have been widely used in the field of power and energy storage, which also puts forward higher requirements for the specific capacity, stability and safety of lithium-ion batteries. Lithium iron phosphate cathode material (LiFePO 4 ), non-toxic, environmentally friendly, rich sources of raw materials, theoretical specific capacity of 170mA / g, voltage platform of 3.5V; and because LiFePO 4 FePO obtained after delithiation 4 It has the same space group and crystal structure (there is a slight difference in the lattice constant), and the volume is only reduced by 6.81%, which will not cause deformation and breakage of the particles, and the electrical contact between particles and...

Claims

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Application Information

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IPC IPC(8): H01M4/04H01M4/136H01M4/1397H01M4/36H01M4/58H01M4/62H01M10/0525
CPCY02E60/10
Inventor 王倩杨成云罗海波张建谢晓华夏保佳
Owner SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
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