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A kind of coated graphite lithium ion battery negative electrode material and preparation method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, batteries, secondary batteries, etc., can solve the problems of poor capacity retention and high working voltage of full batteries, and achieve the purpose of inhibiting the diffusion of oxygen vacancies, improving discharge capacity, and reducing The effect of electrochemical internal resistance

Active Publication Date: 2020-08-04
SOUTH CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The assembled full battery with manganese-based materials paired with graphite has high operating voltage but poor capacity retention

Method used

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  • A kind of coated graphite lithium ion battery negative electrode material and preparation method thereof
  • A kind of coated graphite lithium ion battery negative electrode material and preparation method thereof
  • A kind of coated graphite lithium ion battery negative electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Example 1: Preparation method of coated graphite lithium ion battery negative electrode material

[0035] Include the following steps:

[0036] (1) Pretreatment of graphite: Disperse 0.6g of artificial graphite in 100ml of deionized water (the concentration of graphite dispersed in deionized water is 6g / L), add cationic surfactant cetyltrimethylammonium bromide ( CTAB) 0.02g, ultrasonic dispersion 30min obtains the dilute suspension of graphite;

[0037] (2) Precursor solution Al(OH) 3 Preparation of : at 20 °C, 0.02 g of Al(NO 3 ) 3 ·9H 2 O dissolved in deionized water, and 0.2 mol / L NH 3 ·H 2 The O solution was added dropwise to the three-necked flask at the same time, and the 3 ) 3 ·9H 2The titration rate of the O solution to adjust the titration rate of the ammonia solution in order to adjust the pH=7 (the titration rate should not be too fast to avoid the formation of Al(OH) 3 together). The suspension was then aged with vigorous stirring for an addition...

Embodiment 2

[0047] Example 2: Preparation method of coated graphite lithium ion battery negative electrode material

[0048] Include the following steps:

[0049] (1) Pretreatment of graphite: Disperse 1g of artificial graphite in 100ml of deionized water (the concentration of graphite dispersed in deionized water is 10g / L), add cationic surfactant dodecyldimethylbenzylammonium chloride (1227) 0.05g, ultrasonic dispersion 30min obtains the dilute suspension of graphite;

[0050] (2) Precursor solution Al(OH) 3 Preparation: At 70 °C, dissolve 0.006833 g of aluminum sulfate octadecahydrate in deionized water, and 0.2 mol / L NH 3 ·H 2 The O solution was added dropwise to the three-necked flask at the same time, and the titration rate of the ammonia solution was adjusted at a constant titration rate of the aluminum sulfate solution so as to adjust pH=7 (the dropping rate should not be too fast to avoid the generated Al(OH) 3 together). The suspension was then aged with vigorous stirring f...

Embodiment 3

[0054] Example 3: Refer to Example 2, except that the mass of the cationic surfactant dodecyldimethylbenzylammonium chloride (1227) is 0.0009 g.

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Abstract

The invention discloses a coated graphite lithium ion battery negative electrode material and a preparation method thereof. Under the condition of adding a surfactant, the progress of the coating reaction is effectively controlled by a precipitation conversion method. The surface of the graphite is coated with a layer of nano-scale uniform and dense aluminum phosphate coating, and the ratio of the mass of the aluminum phosphate coating to the mass of the graphite is between 0.1%wt and 10%wt. The aluminum phosphate protective layer can avoid the direct contact between the electrolyte and the graphite, and at the same time prevent the dissolved manganese ions from being reduced to manganese metal on the surface of the graphite. Such a coating layer can improve the cycle stability of the manganese-based cathode material / graphite matched full battery and improve the electrochemical performance of the full battery.

Description

Technical field: [0001] The invention relates to a lithium ion battery, in particular to a negative electrode material of a coated graphite lithium ion battery and a preparation method thereof. Background technique: [0002] Over the past ten years, various types of electric vehicles have occupied an increasing proportion of the market, including hybrid electric vehicles (PHEV) and pure electric vehicles (EV). Lithium-ion batteries are an important enabler in electrifying vehicles due to their high energy density and high power. Commercial lithium-ion batteries (LIBs) use graphite-based carbon anode materials, which have a low charge-discharge platform, but the theoretical specific capacity is only 372 mAh / g, which limits the development of lithium-ion batteries. Since the first reported discovery, high-pressure spinel-type oxide LiNi 0.5 Mn 1.5 O 4 (LNMO) has emerged as an attractive choice for next-generation Li-ion battery cathodes due to its high operating voltage (4...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/583H01M4/62H01M10/0525
CPCH01M4/366H01M4/583H01M4/62H01M4/628H01M10/0525H01M2220/20Y02E60/10
Inventor 吕东生曾环娜陈志祥方丹扬何佳
Owner SOUTH CHINA NORMAL UNIVERSITY
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