Positive electrode containing low-swelling graphite coating and lithium battery

A graphite layer and swelling technology, applied in the direction of batteries, battery electrodes, secondary batteries, etc., can solve the problems of reducing the cycle life of electric vehicles, difficult charging and discharging of electric vehicles, and poor high-current discharge performance, so as to expand the power capacity. range, the effect of increasing the reversible specific capacity, reducing the risk of explosion or fire

Active Publication Date: 2018-11-06
JIANGSU ADVANCED MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Most of the positive electrode materials of lithium-ion batteries are mainly cobalt acid and lithium iron phosphate, among which resources such as Ni and Go are limited, and lithium iron phosphate is relatively safe, but has poor conductivity and low rate performance, which leads to the low temperature of electric vehicles. Difficulties in charging and discharging, etc., reduce the cycle life of electric vehicles
[0004] Graphite has the advantages of low price, wide range of sources, and good conductivity. In the past, there have been cases of using this material to improve the conductivity of the positive active material. However, graphite has a high selectivity to the electrolyte and has poor high-current discharge performance. , will cause graphite volume expansion or swelling, which will weaken the cycle performance of the electrode

Method used

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  • Positive electrode containing low-swelling graphite coating and lithium battery
  • Positive electrode containing low-swelling graphite coating and lithium battery
  • Positive electrode containing low-swelling graphite coating and lithium battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] 1) Mix 32g of phenolic resin-coated LSG, 6g of polyvinylidene fluoride, and 60g of deionized water and carry out planetary stirring at a temperature of 35°C, a rotation speed of 1500rpm / min, and a time of 2h; then add 2g of acetylene black and keep the temperature at 35°C. After stirring at 1000rpm / min for 1h, water-based graphite slurry was obtained;

[0058] 2) Mix and stir 40g lithium manganate and 50g NMP at a temperature of 40°C, a rotation speed of 2000rpm / min, and a time of 2h; add 5g of the above LSG under the same conditions and continue stirring for 1.5h; then add 4g of polyvinylidene fluoride and 1g of acetylene black, Keeping the temperature at 40°C and stirring at 1500rpm / min for 1h, the composite cathode slurry was obtained;

[0059] 3) After passing the above-mentioned water-based graphite slurry through a 100-mesh sieve, coat it on one side of an aluminum foil (10 μm thick) to form an LSG layer, dry it, and the coating thickness is 20 μm;

[0060] 4) Co...

Embodiment 2

[0063] 1) Mix 34g of PVDF-coated LSG, 4.8g of styrene-butadiene rubber, and 60g of deionized water and carry out planetary stirring at a temperature of 40°C and a rotation speed of 1000rpm / min for 1.5h; then add 1.2g of conductive carbon black and keep the temperature at 40 °C, after stirring at 1500rpm / min for 1h, an aqueous graphite slurry was obtained;

[0064] 2) Mix and stir 42.5g lithium cobaltate and 50g NMP at a temperature of 35°C and a rotation speed of 2500rpm / min for 3h; add 5g of the above LSG under the same conditions and continue stirring for 2h; then add 2g of styrene-butadiene rubber and 0.5g of conductive carbon black , keep the temperature at 35°C, and stir at 2000rpm / min for 0.5h to obtain the composite cathode slurry;

[0065] 3) After passing the above-mentioned water-based graphite slurry through a 100-mesh screen, coat it on one side of an aluminum foil (10 μm thick) to form an LSG layer, dry it, and the coating thickness is 25 μm;

[0066] 4) Coat the...

Embodiment 3

[0069] 1) Mix 31.5g of epoxy resin-coated LSG, 2.8g of styrene-acrylic emulsion, and 65g of deionized water and carry out planetary stirring at a temperature of 25°C and a rotation speed of 2500rpm / min for 2h; then add 0.7g of carbon fiber and keep the temperature at 25 °C, after stirring at 2000rpm / min for 1.5h, an aqueous graphite slurry was obtained;

[0070] 2) Mix and stir 31.5g lithium iron phosphate and 65g NMP at a temperature of 30°C and a rotation speed of 2000rpm / min for 3h; add 2.1g of the above LSG under the same conditions and continue stirring for 2.5h; then add 1.05g of styrene-acrylic emulsion, 0.35g Carbon fiber, keep the temperature at 30°C, and stir at 1500rpm / min for 1.5h to obtain the composite positive electrode slurry;

[0071] 3) Pass the above-mentioned water-based graphite slurry through a 100-mesh sieve, and coat it on one side of an aluminum foil (10 μm thick) to form an LSG layer, then dry it, and the coating thickness is 15 μm;

[0072]4) Coat t...

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Abstract

The invention relates to a positive electrode containing a low-swelling graphite coating and a lithium battery containing the positive electrode. The positive electrode comprises a positive electrodecurrent collector, a low-swelling graphite layer, a first composite coating and a second composite coating, wherein one side of the positive electrode current collector is coated with the low-swellinggraphite layer; the low-swelling graphite layer is coated with the first composite coating; the other side of the positive electrode current collector is coated with the second composite coating; each of the first composite coating and the second composite coating is an independent mixed coating formed by a positive electrode active substance and low-swelling graphite; and the tap density of thelow-swelling graphite is 0.9-1.4g/cm<3>. After the positive electrode is assembled into a battery, the charge and discharge cycle performance and the safety performance of the battery can be improved.

Description

technical field [0001] The disclosure relates to the technical field of lithium batteries, in particular to a positive electrode containing a low-swellable graphite coating and a lithium battery comprising the positive electrode. Background technique [0002] In recent years, in the field of new energy vehicles, the demand for lithium-ion batteries has increased year by year. Since the specific capacity of the positive electrode material is much smaller than that of the negative electrode material, but the capacity of the battery is determined by the capacity of the positive electrode material, it is imminent to develop a high capacity and high power type positive electrode material. [0003] Most of the positive electrode materials of lithium-ion batteries are mainly cobalt acid and lithium iron phosphate. Among them, resources such as Ni and Go are limited. Lithium iron phosphate has better safety, but poor conductivity and low rate performance, resulting in low temperatur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/131H01M4/136H01M4/1391H01M4/1397H01M4/04H01M10/0525
CPCH01M4/0404H01M4/131H01M4/136H01M4/1391H01M4/1397H01M10/0525H01M2220/20Y02E60/10
Inventor 杨浩田王晓明刘勇标黄云
Owner JIANGSU ADVANCED MATERIAL TECH CO LTD
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