Preparation method of positive composite material of graphene-lithium battery

A technology of composite materials and positive electrode materials, which is applied in the field of preparation of graphene-lithium battery positive electrode composite materials, can solve the problems of weak coating layer force, poor electrolyte compatibility, and surface layer peeling, so as to improve volume specific capacity, Effects of high capacity stability and high cycle life

Inactive Publication Date: 2014-01-08
LUXI GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the weak force between the coating layers and poor compatibility with the electrolyte, solvent molecules will enter the coating layer during charging and discharging, causing the surface layer to peel off, and the electr

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Take 5Kg of lithium cobaltate and put it in a 100L reaction kettle, add 500g of graphene dry powder, 60L of distilled water, 20g of polyethylene glycol with a molecular weight of 400, add an aqueous solution of hydrogen chloride to adjust the acidity of the reaction solution to pH=2.6, stir, and heat the reaction solution to 50 °C for 4 hours; the resulting slurry was centrifuged to separate the solid from the liquid to obtain a solid product; the separated solid product was heated to 600 °C in a tube furnace under the protection of a nitrogen atmosphere, kept for one hour and then naturally cooled to obtain the product.

[0021] A charge-discharge instrument was used to conduct constant current charge-discharge tests to test the performance of lithium battery cathode materials. The experimental cells were assembled in an argon-filled glove box (H 2 O2 6 / EC+DMC+DEC (volume ratio 1:1:1); the diaphragm is Celgard2400 diaphragm; the counter electrode is metal lithium shee...

Embodiment 2

[0027] Take 5Kg of lithium iron phosphate and put it in a 100L reactor, add 125g of graphene, 80L of distilled water and a mixed solvent of dimethylformamide (the volume ratio of water and dimethylformamide is 3:1), 12.5g of polyvinyl alcohol, Add an anhydrous ethanol solution of lithium ethoxide to adjust the acidity of the reaction solution to pH=1.6, stir, and heat the reaction solution to 80°C for 14 hours; centrifuge the obtained slurry to separate the solid and liquid to obtain a solid product; the separated solid product Under the protection of nitrogen atmosphere in a tube furnace, the temperature was first raised to 200°C and kept for one hour; then the temperature was raised to 400°C and kept for 30 minutes; finally the temperature was raised to 600°C and kept for 90 minutes to obtain the product by natural cooling.

Embodiment 3

[0029] Take 8Kg of lithium manganate and put it in a 100L reaction kettle, add 100g of graphite milk, 70L of N-methylpyrrolidone, 160g of polyacrylamide, add an anhydrous ethanol solution of hydrogen chloride to adjust the hydrogen ion concentration to 1.0mol / L, stir, and heat to react liquid to 40°C for 40 hours; centrifuge the obtained slurry to separate the solid and liquid to obtain a solid product; heat the separated solid product to 500°C in a tube furnace under the protection of a nitrogen atmosphere, keep it for three hours and then cool it naturally get the product.

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Abstract

The invention discloses a preparation method of a positive composite material of a graphene-lithium battery. The preparation method comprises the following steps of (1) performing coprecipitation-loading on graphene, a graphene precursor, graphene powder or graphene dispersion and a positive material of a lithium battery, namely adding the graphene, the graphene precursor, the graphene powder or the graphene dispersion and the positive material of the lithium battery in the mass ratio of 1:8 to 1:100 into a solvent to keep the concentration at 1-120 g/L, then adding auxiliaries which is 1-10 mass percent of the grapheme, adjusting the hydrogen ion concentration to be 1.0*10<-5> to 1.0*10<2> mol/L through a pH value adjustment agent, and mixing at the temperature of 10-80 DEG C for 1-96 hours to obtain a loaded product; (2) performing centrifugal separation on the loaded product, wherein one product is a solid sample; (3) roasting the separated solid sample at the temperature of 400-700 DEG C for 0.5-4 hours, and performing activation to obtain the positive composite material of the graphene-lithium battery. The preparation method disclosed by the invention has the beneficial effects that the volume specific capacity and the attenuation resistance are improved, the cycle life is long, and the capacity stability is high.

Description

technical field [0001] The invention relates to a preparation method of a lithium battery cathode material, in particular to a preparation method of a graphene-lithium battery cathode composite material. Background technique [0002] Lithium batteries are now widely used in portable devices such as mobile phones, notebook computers and digital electronic products. Aspects such as stability and cycle life can no longer meet the needs of the market. [0003] At present, carbon coating is one of the most important methods to improve the capacity, rate performance and cycle stability of lithium battery cathode materials. The carbon coating uses inorganic or organic carbon sources, and its main function is to improve the conductivity of the lithium battery cathode material particles, so that the material can obtain good performance at high rates. However, due to the weak force between the coating layers and poor compatibility with the electrolyte, solvent molecules will enter t...

Claims

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Application Information

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IPC IPC(8): H01M4/505H01M4/525H01M4/58
CPCY02E60/122H01M4/366H01M4/505H01M4/525H01M4/5825H01M4/625H01M10/052Y02E60/10
Inventor 张文景海伟曹全福
Owner LUXI GRP
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