Preparation method of graphene-multi-element metal positive electrode material

A cathode material and multi-metal technology, which is applied in the field of graphene-multi-metal cathode material preparation, can solve problems such as accelerated electrolyte decomposition, and achieve the effects of long service life, high specific capacity, improved electrical conductivity and cycle stability

Inactive Publication Date: 2014-05-21

詹炳辉

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AI-Extracted Technical Summary

Problems solved by technology

Li-Mn-O and Li-Ni-Co-O materials are slightly better than Li-Co-O when they are overcharged, but the Mn or Ni ions produced...

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Abstract

The invention relates to a preparation method of a graphene-multi-element metal positive electrode material. The method comprises the following steps: (1) weighing lithium hydroxide, magnesium oxide, manganese oxide, aluminium hydroxide, cobaltous oxide and zirconia according to the molar weights of Li, Mg, Mn, Al, Co and Zr in the chemical formula of Li(1-x)MgxMn(1-y)AlyCo(1-z)ZrzO4, wherein x is equal to 0.2-0.25, y is equal to 0.1-0.3, and z is equal to 0.05-0.1, mechanically mixing, carrying out ball milling, and drying so as to obtain powder, crushing, and sintering so as to obtain the multi-element metal positive electrode material; (2) preparing powdery graphene; and (3) mixing the powdery graphene and a polyethylene glycol solution, ultrasonically dispersing the mixture into ethyl alcohol to form a conductive graphene dispersive liquid; mixing the multi-element metal positive electrode material with the conductive graphene dispersive liquid, carrying out ball milling, drying, and sintering so as to prepare the graphene-multi-element metal positive electrode material. According to the graphene-multi-element metal positive electrode material prepared by the invention, active substances are formed by utilizing the multi-element metal material, and the surface of the graphene-multi-element metal positive electrode material is coated with a graphene material prepared by a specific method, and the activity and the stability of the material are improved.

Application Domain

Cell electrodesSecondary cells

Technology Topic

Cvd grapheneManganese oxide +10

Examples

Experimental program(2)
Comparison scheme(1)

Example Embodiment

[0020] Embodiment one

[0021] The chemical formula of the multi-element metal cathode material is Li 0.8 Mg 0.2 mn 0.9 Al 0.1 co 0.95 Zr 0.05 o 4 According to the molar weight of Li, Mg, Mn, Al, Co, Zr in the above chemical formula, lithium hydroxide, magnesium oxide, manganese oxide, aluminum hydroxide, cobalt oxide and zirconium oxide were weighed, mechanically mixed, and placed in a planetary ball mill Ball mill at a speed of 400r/min for 8 hours; after ball milling, put it in a vacuum dryer and dry at a temperature of 150°C for 18 hours to obtain a powder, and crush the obtained powder with a crushing equipment; put the crushed powder in a reducing atmosphere furnace at 900 Sintering at a temperature of ℃ for 6h to obtain a multi-element metal positive electrode material.

[0022] Weigh graphite and potassium permanganate according to the mass ratio of 1:3, first add graphite to the mixed solution of 95wt% concentrated sulfuric acid and 60wt% concentrated nitric acid with a volume ratio of 2:1, and then gradually add permanganese Potassium acid, carry out oxidation reaction, control the reaction temperature at 1 °C, after 36 hours of reaction, wash with 15wt% dilute hydrochloric acid solution and deionized water repeatedly until no chloride ion is detected and the pH value reaches neutral, then dry in vacuum , pulverized to obtain graphite oxide powder.

[0023] The graphite oxide powder is subjected to rapid heat treatment for 20 seconds at 1000°C under an air atmosphere to obtain exfoliatable graphite. Disperse the exfoliatable graphite in absolute ethanol, place it under the ultrasonic condition of 300W power and disperse for 3 hours to obtain a graphene suspension, and then dry it in vacuum at low temperature to obtain powdered graphene.

[0024] The above powdered graphene is mixed with polyethylene glycol at a weight ratio of 1:1 and ultrasonically dispersed into ethanol to form a conductive graphene dispersion. Mix the above-mentioned multi-component metal cathode material with the conductive graphene dispersion in a ratio of 100:3 by weight, and ball mill the mixture for 15 hours at a speed of 400r/min in a planetary ball mill; Carry out heat treatment and sintering at a temperature of 5°C/min, sinter at a constant temperature of 750°C for 15 hours, and cool down at 10°C/min to prepare the product.

Example Embodiment

[0025] Embodiment two

[0026] The chemical formula of the multi-element metal cathode material is Li 0.75 Mg 0.25 mn 0.7 Al 0.3 co 0.9 Zr 0.1 o 4 According to the molar weight of Li, Mg, Mn, Al, Co, Zr in the above chemical formula, lithium hydroxide, magnesium oxide, manganese oxide, aluminum hydroxide, cobalt oxide and zirconium oxide were weighed, mechanically mixed, and placed in a planetary ball mill Ball mill at a speed of 500r/min for 6 hours; after ball milling, place in a vacuum dryer and dry at 200°C for 12 hours to obtain powder, and crush the obtained powder with a crushing equipment; place the crushed powder in a reducing atmosphere furnace at 1000 Sintering at a temperature of ℃ for 5h to obtain a multi-element metal positive electrode material.

[0027] Weigh graphite and potassium permanganate according to the mass ratio of 1:5, first add graphite to the mixed solution of 95wt% concentrated sulfuric acid and 60wt% concentrated nitric acid with a volume ratio of 3:1, and then gradually add permanganese Potassium acid, carry out oxidation reaction, control the reaction temperature at 2°C, after 24 hours of reaction, wash with 15wt% dilute hydrochloric acid solution and deionized water repeatedly until no chloride ion is detected and the pH value reaches neutral, then dry in vacuum , pulverized to obtain graphite oxide powder.

[0028] The graphite oxide powder is subjected to a rapid heat treatment at 1100°C for 10 seconds under an air atmosphere to obtain exfoliatable graphite. Disperse the exfoliatable graphite in absolute ethanol, place it under ultrasonic conditions of 500W power and disperse for 2 hours to obtain a graphene suspension, and then dry it in vacuum at low temperature to obtain powdered graphene.

[0029] The above powdered graphene is mixed with polyethylene glycol at a weight ratio of 1:2 and ultrasonically dispersed into ethanol to form a conductive graphene dispersion. Mix the above-mentioned multi-element metal positive electrode material with the conductive graphene dispersion in a ratio of 100:5 by weight, and ball mill the mixture for 10 h at a speed of 500 r/min in a planetary ball mill; Carry out heat treatment and sintering in 10°C/min, heat up at a rate of 10°C/min, sinter at a constant temperature of 800°C for 10h, and cool down at 15°C/min to prepare the product.

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Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Improve electrical conductivity and cycle stability
Improve activity and stability

Preparation method of coated lithium iron phosphate positive electrode material

InactiveCN107123798AImprove electrical conductivity and cycle stabilityHigh first discharge reversible capacityCell electrodesSecondary cellsLiquid phaseElectrode material

Owner:SUZHOU SICHUANGYUANBO ELECTRONICS TECH CO LTD

Preparation method of graphene-multi-element metal positive electrode material

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Examples

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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