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Method for preparing graphene composite lithium-rich positive electrode material through solvent-assisted reducing agent method

A lithium-rich cathode material and graphene composite technology, applied in the direction of positive electrodes, battery electrodes, active material electrodes, etc., can solve the problems of poor cycle stability and low first-cycle efficiency, and achieve reduced polarization, rate performance and cycle performance Enhanced and compounded effect

Inactive Publication Date: 2018-11-16
SHANDONG UNIV OF TECH
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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 provide a method for preparing graphene composite lithium-rich positive electrode material by solvent-assisted reducing agent method. The method combines graphene and lithium-rich positive electrode material. The process flow is simple and mild, the composite material has high rate performance and discharge specific capacity. High, fully improve the shortcomings of low first-cycle efficiency and poor cycle stability of lithium-rich cathode materials

Method used

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  • Method for preparing graphene composite lithium-rich positive electrode material through solvent-assisted reducing agent method
  • Method for preparing graphene composite lithium-rich positive electrode material through solvent-assisted reducing agent method
  • Method for preparing graphene composite lithium-rich positive electrode material through solvent-assisted reducing agent method

Examples

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Effect test

Embodiment 1

[0022] In this example, glucose is used as the reducing agent, and the graphene composite cathode material prepared in ethanol solvent is 0.4Li2MnO3·0.4Li[Ni1 / 3Co1 / 3Mn1 / 3]O2 / GO.

[0023] Prepare 2mol / L Ni(CH3COO)2·4H2O, Co(CH3COO)2·4H2O and Mn(CH3COO)2·4H2O metal salt mixed solution A according to the stoichiometric ratio, prepare 4mol / L Na2CO3 and 1.5mol / L In a 5L reactor, A and B were mixed and co-precipitated, the pH of the reaction was controlled to be 9, the rotation speed was 800rpm / min, the temperature was 50 degrees, the reaction was 24h, and the stirring and aging was completed for 24h. Suction filter out the precipitate, dry it, weigh an excess of 5% Li2CO3 according to the metering ratio, mix and ball mill it, put it into a muffle furnace, raise the temperature from room temperature to 500°C in 3 hours, keep it warm for 5 hours, and then raise the temperature to 900°C in 5 hours. Keep it warm for 12 hours, then grind it for 20 minutes after cooling in the furnace to...

Embodiment 2

[0027] In this example, glucose is used as the reducing agent, and the graphene composite cathode material prepared in ethylene glycol solvent is 0.6Li2MnO3·0.1Li[Ni0.4Co0.2Mn0.2]O2 / GO.

[0028] Prepare 0.5mol / L Ni(CH3COO)2·4H2O, Co(CH3COO)2·4H2O and Mn(CH3COO)2·4H2O metal salt mixed solution A according to the stoichiometric ratio, prepare 1mol / L NaOH and 1.2mol / L Mix L of ammonia solution B, in a 1L beaker, mix and co-precipitate A and B, control the pH of the reaction to 11, rotate at 1000rpm / min, and temperature at 55 degrees, react for 4h, and finish stirring and aging for 24h. Suction filter out the precipitate, dry it, weigh an excess of 5% LiOH according to the metering ratio, mix and ball mill it, put it into a muffle furnace, raise the temperature from room temperature to 550°C in 3 hours, keep it warm for 5 hours, and then raise the temperature to 920°C in 5 hours. Keep it warm for 12 hours, then grind for 20 minutes after cooling in the furnace, and then obtain the...

Embodiment 3

[0032] In this example, ascorbic acid was used as the reducing agent, and the graphene composite cathode material prepared in NMP (nitrogen-methylpyrrolidone) solvent was 0.4Li2MnO3·0.4Li[Ni0.5Co0.2Mn0.3]O2 / GO.

[0033] Prepare 1mol / L Ni(CH3COO)2 4H2O, Co(CH3COO)2 4H2O and Mn(CH3COO)2 4H2O metal salt mixed solution A according to the stoichiometric ratio, prepare 2mol / L NaOH and 1.2mol / L In a 1L beaker, mix and co-precipitate A and B, control the pH of the reaction to 9, rotate at 900 rpm / min, and temperature at 50 degrees, react for 12 hours, and finish stirring and aging for 24 hours. Suction filter out the precipitate, dry it, weigh an excess of 5% Li2CO3 according to the metering ratio, mix and ball mill it, put it into a muffle furnace, raise the temperature from room temperature to 500°C in 3 hours, keep it warm for 5 hours, and then raise the temperature to 900°C in 5 hours. Keep it warm for 12 hours, then grind for 20 minutes after cooling in the furnace, and then obta...

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Abstract

The invention belongs to the technical field of lithium ion battery material and graphene composite material preparation, and specifically discloses a method for preparing a graphene composite lithium-rich positive electrode material through a solvent-assisted reducing agent method. The method comprises the following steps: (1) preparing a lithium-rich positive electrode material: taking an Ni-Co-Mn metal salt solution, sodium carbonate and an ammonia water solution into a reaction still to perform a coprecipitation reaction, cleaning and drying a precipitate, and after adding a lithium salt for ball-milling, carrying out high-temperature calcinations for several hours to obtain the lithium-rich positive electrode material; and (2) preparing a composite material: after dissolving oxidizedgraphene into a solvent, adding a reducing agent and the lithium-rich positive electrode material, and dropwise adding ammonia water to react so as to obtain the graphene composite lithium-rich positive electrode material. The graphene prepared in the invention is higher in purity and high in composition degree with the lithium-rich positive electrode material, the electronic conductivity of the material is improved through high conductivity and a special two-dimensional netted transmission structure, the polarization is reduced, and the rate capability and cycle performance of the lithium-rich positive electrode material are obviously improved.

Description

technical field [0001] The invention belongs to the technical field of preparation of lithium-ion battery materials and graphene composite materials, in particular to a method for preparing graphene composite lithium-rich cathode materials by a solvent-assisted reduction method. Background technique [0002] In recent years, in response to the negative impacts such as environmental pollution and the sharp consumption of oil resources brought about by the rapid development of the automobile industry, countries are actively carrying out research on electric vehicles EV and hybrid electric vehicles HEV using clean energy. With the vigorous development of new energy sources such as electric vehicles and energy storage power stations, people have put forward higher requirements for the energy density, power density and cycle life of the next generation of high-performance lithium-ion batteries. At present, commercial lithium-ion batteries mainly use LiCoO2 as the positive electro...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/505H01M4/525H01M4/62H01M10/0525
CPCH01M4/362H01M4/505H01M4/525H01M4/625H01M10/0525H01M2004/021H01M2004/028Y02E60/10
Inventor 温广武王桢
Owner SHANDONG UNIV OF TECH
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