Preparation method of graphene-coated lithium nickel cobalt manganate composite material

A nickel-cobalt lithium manganese oxide and graphene-coated technology, applied in the field of materials, can solve problems such as accumulation of solid electrolyte membranes, irreversible phase transitions, cracks in grains, etc., achieve pollution-free preparation, and solve the effects of low energy density

Active Publication Date: 2018-04-13
FUDAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the problems of irreversible phase transition, cracks in grains, and accumulation of solid electrolyte film during the charge and discharge process of lithium nickel cobalt manganese oxide, and provide an environmentally friendly, low-cost, and process-controllable graphene-coated Preparation method of nickel-cobalt lithium manganate composite material

Method used

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  • Preparation method of graphene-coated lithium nickel cobalt manganate composite material
  • Preparation method of graphene-coated lithium nickel cobalt manganate composite material
  • Preparation method of graphene-coated lithium nickel cobalt manganate composite material

Examples

Experimental program
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Effect test

Embodiment 1

[0030](1) Prepare 700 mL of 0.015 mol / L manganese sulfate aqueous solution and 0.15 mol / L ammonium bicarbonate aqueous solution with deionized water respectively, then add 70 mL of ethanol to the manganese sulfate aqueous solution, and then add the ammonium bicarbonate aqueous solution dropwise to Manganese sulfate aqueous solution, magnetically stirred for 1 h, suction filtered, washed with water, and freeze-dried to obtain manganese carbonate powder; then put the manganese carbonate powder in a tube furnace and calcined for 5 h in an air atmosphere at 400°C to obtain spherical manganese dioxide powder ;

[0031] (2) Using the manganese dioxide (0.054 mol / L) obtained in step (1) as a template, impregnate in a solution containing nickel acetate (0.013 mol / L), cobalt acetate (0.013 mol / L) and lithium hydroxide (0.12 mol / L) L) in an ethanol solution, ultrasonically dispersed and stirred at room temperature until the ethanol volatilized to obtain a mixture; then the mixture was g...

Embodiment 2

[0036] (1) Prepare 700 mL of 0.015 mol / L manganese sulfate aqueous solution and 0.15 mol / L ammonium bicarbonate aqueous solution with deionized water respectively, then add 105 mL of ethanol to the manganese sulfate aqueous solution, and then add the ammonium bicarbonate aqueous solution dropwise to Manganese sulfate aqueous solution, magnetically stirred for 1 h, suction filtered, washed with water, and freeze-dried to obtain manganese carbonate powder; then put the manganese carbonate powder in a tube furnace and calcined for 3 h in an air atmosphere at 400°C to obtain spherical manganese dioxide powder ;

[0037] (2) Using the manganese dioxide (0.055 mol / L) obtained in step (1) as a template, impregnate in a solution containing nickel acetate (0.015 mol / L), cobalt acetate (0.01 mol / L) and lithium hydroxide (0.12 mol / L) L) in an ethanol solution, ultrasonically dispersed and stirred at room temperature until the ethanol volatilized to obtain a mixture; then the mixture was ...

Embodiment 3

[0041] (1) Prepare 700 mL of 0.02 mol / L manganese sulfate aqueous solution and 0.2 mol / L ammonium bicarbonate aqueous solution with deionized water respectively, then add 70 mL of ethanol to the manganese sulfate aqueous solution, and then add the ammonium bicarbonate aqueous solution dropwise to Manganese sulfate aqueous solution, magnetically stirred for 1 h, suction filtered, washed with water, and freeze-dried to obtain manganese carbonate powder; then put the manganese carbonate powder in a tube furnace and calcined for 4 h in an air atmosphere at 400°C to obtain spherical manganese dioxide powder ;

[0042] (2) Using the manganese dioxide (0.054 mol / L) obtained in step (1) as a template, impregnate in a solution containing nickel acetate (0.013 mol / L), cobalt acetate (0.013 mol / L) and lithium hydroxide (0.12 mol / L) L) in an ethanol solution, ultrasonically dispersed and stirred at room temperature until the ethanol volatilized to obtain a mixture; then the mixture was gr...

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Abstract

The invention discloses a preparation method of a graphene-coated lithium nickel cobalt manganate composite material. The method comprises the following steps of preparing graphene with properties ofeasy separation, high water dispersity and high electrical conductivity in a green and efficient manner by combination of a water phase "intercalation-expansion-oxidization" method and a gamma-ray irradiation reduction technology; by adopting a high-temperature calcining method and by taking spherical manganese dioxide as a template, skillfully preparing a spherical ternary material which has a hollow structure and is formed by nanometer lithium nickel cobalt manganate primary particles, and performing surface modification treatment on the spherical ternary material; and further controlling proper conditions to enable graphene to be uniformly and firmly coated on the surface of lithium nickel cobalt manganate to obtain the target composite material. The raw materials involved in the invention are low in cost, the preparation process is high in controllability, and adopted water or an ethyl alcohol solvent is environment friendly; the composite material is excellent in electrochemical performance; the specific capacity can be as high as 265 mAh g<-1>; and after 500 cycles, the capacity retention rate can be 86%, so that the composite material can be widely applied to the lithium ionbattery and other electrochemical energy storage devices.

Description

technical field [0001] The invention belongs to the technical field of materials, and relates to a preparation method of a graphene-coated nickel-cobalt-lithium manganese oxide composite material. Specifically, it combines the water phase "intercalation-expansion-oxidation" method and the γ-ray irradiation reduction technology to prepare green and efficient graphene that is easy to separate, has good water dispersibility, and high conductivity. Using the high-temperature calcination method and using spherical manganese dioxide as a template, a spherical ternary material with a hollow structure and nano-sized nickel-cobalt-lithium manganese oxide primary particles is cleverly prepared, and its surface is modified. Then control the appropriate conditions so that the graphene can be evenly and firmly coated on the surface of nickel-cobalt-lithium manganese oxide, and the target composite material can be obtained. The composite material has excellent electrochemical properties an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36
CPCH01M4/362Y02E60/10
Inventor 卢红斌孙敏强
Owner FUDAN UNIV
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