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Composite modified graphite negative electrode material and preparation method thereof

A graphite negative electrode and composite modification technology, which is applied in the direction of graphite, chemical instruments and methods, nickel compounds, etc., can solve the problems of reducing ion conductivity, high equipment requirements, and difficulty in expanding production, and achieve volume specific capacity. Large-scale production, avoiding the effect of poor cycle performance

Active Publication Date: 2021-02-19
昆明云大新能源有限公司
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  • Claims
  • Application Information

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Problems solved by technology

The rate performance and cycle performance of the obtained manganese oxide-small-sized micro-diffusion layer natural graphite anode have been significantly improved compared with natural flake graphite, but due to the use of concentrated sulfuric acid as an intercalation agent, some of the obtained anode materials will be Sulfur element remains, and the intermediate product of sulfur during charging and discharging will dissolve into the electrolyte, increasing the viscosity of the electrolyte and reducing the ion conductivity. At the same time, the combination product of sulfur and lithium ions, Li 2 S n It is electronically insulating and insoluble in the electrolyte. It is deposited on the conductive framework to reduce the conductivity of the entire negative electrode, resulting in poor performance of the entire negative electrode. It is currently not suitable for use in the field of lithium-ion batteries
[0005] The commercialized graphite negative electrode has low specific capacity, poor rate performance, and poor cycle performance, and the existing schemes for modifying graphite have complex operations, high costs, high equipment requirements, difficulty in expanding production, and insignificant product performance improvement. There are problems such as defects in the composition, which seriously hinders the development of high-performance lithium-ion batteries

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  • Composite modified graphite negative electrode material and preparation method thereof
  • Composite modified graphite negative electrode material and preparation method thereof
  • Composite modified graphite negative electrode material and preparation method thereof

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preparation example Construction

[0039] A kind of preparation method of composite modified graphite negative electrode material of the present invention comprises the following steps:

[0040] 1) Mix graphite with oxidant and intercalant according to a certain mass ratio to obtain a mixed solution;

[0041] 2) stirring the mixed solution under constant temperature conditions to obtain intercalation products;

[0042] 3) Repeatedly washing the intercalation product with deionized water until the pH of the filtrate is between 5-7, then drying the washed intercalation product, and then calcining in an inert atmosphere to raise the temperature to the target temperature and keep it warm for a specific time After that, the target object is obtained.

[0043] In the step 1, the mass ratio of graphite to oxidant and intercalant is 1:1-10:1-10.

[0044] The graphite is a mixture of one or more of natural graphite, artificial graphite, spherical graphite, graphite mesophase, the particle size of the graphite is 1-60 ...

Embodiment 1

[0054] Artificial graphite anode materials with a particle size of 20 μm and a purity of 99wt% were mixed with 99.99% potassium permanganate and 50% nitric acid at a ratio of 1 g: 0.4 g: 4 mL, and stirred at 40 °C at a speed of 1000 rpm for 12 h, then use deionized water to wash and filter the product solid at room temperature until the pH of the filtrate is 5, and dry the product solid at 30 °C for 24 h, then heat up to 1 °C / min in a tube furnace under a nitrogen atmosphere. Calcined at 650 °C for 2 h to obtain a composite modified graphite anode material, that is, manganese oxide-loaded sulfur-free micro-expanded graphite for lithium-ion battery anode materials.

Embodiment 2

[0056] Artificial graphite anode material with a particle size of 20 μm and a purity of 89wt% was mixed with 99% potassium permanganate and 70% concentrated nitric acid at a ratio of 1 g: 1.46 g: 4 mL, and stirred at 40 °C at a speed of 1000 rpm for 12 h, then use deionized water to wash and filter the product solid at room temperature until the pH of the filtrate is 6, dry the product solid at 60°C for 12 h, then heat up at 10°C / min in a tube furnace under an argon atmosphere Calcined at 650 °C for 12 h to obtain composite modified graphite anode material.

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Abstract

The invention discloses a composite modified graphite negative electrode material and a preparation method thereof. The preparation method comprises the following steps: 1) mixing graphite, an oxidantand an intercalator according to a certain mass ratio to obtain a mixed solution; 2) carrying out stirring reaction on the mixed solution under a constant temperature condition to obtain an intercalation product; and 3) repeatedly washing the intercalation product with deionized water until the pH value of the filtrate is 57, drying the washed intercalation product, heating to a target temperature in an inert atmosphere, and keeping the temperature for a specific time to obtain the target object. The composite modified graphite negative electrode material prepared by the method disclosed by the invention is manganese oxide loaded sulfur-free micro-expanded graphite, and has nanopores and properly enlarged graphite lamellar spacing. The method has the advantages of being high in operability, easy to produce, low in equipment requirement and good in repeatability, and the prepared composite modified graphite negative electrode material has high specific capacity, excellent rate capability and long cycling stability and is easier to use in the field of commercial lithium ion batteries.

Description

technical field [0001] The invention belongs to the technical field of graphite materials, and in particular relates to a composite modified graphite negative electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] Compared with other electrochemical batteries (such as lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries), lithium-ion batteries have higher energy density and power density, long cycle life, high working voltage, good safety performance and environmental friendliness And other characteristics, has been widely used in portable electronic devices, and is being gradually promoted into new energy vehicles, renewable energy storage, energy saving and emission reduction and other fields. Structurally, lithium-ion batteries can be divided into four parts: the positive electrode that provides the lithium source, the negative electrode that can intercalate lithium, the separator that prevents...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G53/00C01B32/22C01B32/225C01G45/02H01M4/36H01M4/50H01M4/587H01M10/0525H01M10/058
CPCC01G53/006C01B32/22C01B32/225C01G45/02H01M4/366H01M4/502H01M4/587H01M10/058H01M10/0525C01P2002/72C01P2004/03Y02E60/10Y02P70/50
Inventor 卢文向富维刘哲栋陈小春
Owner 昆明云大新能源有限公司
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