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A kind of lithium titanate coated graphite composite material and preparation method thereof

A technology of lithium titanate coating and composite materials, which is applied in the field of lithium-ion batteries, can solve the problems of difficult formation of SEI film, limited low-temperature performance of batteries, and low initial charge-discharge efficiency, so as to improve the first-time charge-discharge efficiency and increase Structural stability and lithium ion transport rate, effect of improving low-temperature performance

Active Publication Date: 2017-06-20
RIGHTFUL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, the potential of lithium titanate is relatively high, about 1.55V. When used as a negative electrode material for batteries, it is difficult to form an SEI film with electrolyte decomposition products.
Therefore, coating lithium titanate on the surface of graphite material will hinder the formation of SEI film on the surface of graphite material, which is not conducive to the interface stability of graphite material when discharging at low temperature, resulting in limited low temperature performance of the battery and low initial charge and discharge efficiency.

Method used

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  • A kind of lithium titanate coated graphite composite material and preparation method thereof
  • A kind of lithium titanate coated graphite composite material and preparation method thereof
  • A kind of lithium titanate coated graphite composite material and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0053] The preparation method of the lithium titanate-coated graphite composite material of the present embodiment comprises the following steps:

[0054] 1) Solution preparation:

[0055] 40g tetrabutyl titanate, 0.4g LiAlO 2 Mix evenly with 90g ethanol to obtain solution A;

[0056] 10g CH 3 COOLi·2H 2 O, 0.5g K 2 CO 3 Mix with 90g ethanol to obtain solution B;

[0057] 2) Preparation of coating precursor:

[0058] Add 100g of graphite into 900g of ethanol to obtain graphite-ethanol mixed solution, and add solution A and solution B obtained in step 1) into the graphite-ethanol mixed solution at a rate of 50mL / min respectively. , stirring at a speed of 400 rpm, while applying ultrasonic vibration, mixing and reacting until the ethanol is completely evaporated to dryness, and the coated precursor powder is obtained.

[0059] 3) Sintering:

[0060] The coated precursor powder obtained in step 2) was sintered at 800° C. for 6 hours to obtain a lithium titanate coated gr...

Embodiment 2

[0063] The preparation method of the lithium titanate-coated graphite composite material of the present embodiment comprises the following steps:

[0064] 1) Solution preparation:

[0065] 30g of tetrabutyl titanate, 0.3g of LiAlO 2 Mix evenly with 80g ethanol to obtain solution A;

[0066] 10g CH 3 COOLi·2H 2 O, 0.1 g of K 2 CO 3 Mix with 80g ethanol to obtain solution B;

[0067] 2) Preparation of coating precursor:

[0068] Add 100g of graphite into 800g of ethanol to obtain graphite ethanol mixed solution, and add solution A and solution B obtained in step 1) into the ethanol mixed solution of graphite at a rate of 10mL / min respectively. , stirring at a speed of 300 rpm, while applying ultrasonic vibration, mixing and reacting until the ethanol is completely evaporated to dryness, and the coating precursor powder is obtained.

[0069] 3) Sintering:

[0070] The coated precursor powder obtained in step 2) was sintered at 700° C. for 8 hours to obtain a graphite com...

Embodiment 3

[0073] The preparation method of the lithium titanate-coated graphite composite material of the present embodiment comprises the following steps:

[0074] 1) Solution preparation:

[0075] 50g tetrabutyl titanate, 0.5g LiAlO 2 Mix evenly with 100g ethanol to obtain solution A;

[0076] 10g CH 3 COOLi·2H 2 O, 1g of K 2 CO 3 Mix with 100g ethanol to obtain solution B;

[0077] 2) Preparation of coating precursor:

[0078] Add 100g of graphite into 800g of ethanol to obtain graphite-ethanol mixed solution, and add the solution A and solution B obtained in step 1) into the graphite-ethanol mixed solution at a rate of 100mL / min, respectively. , stirred at a speed of 500 rpm, and applied ultrasonic vibration at the same time, mixed and reacted until the ethanol was completely evaporated to dryness, and the coated precursor powder was obtained.

[0079] 3) Sintering:

[0080] The coated precursor powder obtained in step 2) was sintered at 900° C. for 4 hours to obtain a grap...

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Abstract

The invention relates to a lithium titanate-coated graphite composite material and a preparation method thereof, and belongs to the technical field of lithium-ion batteries. The preparation method of the lithium titanate-coated graphite composite material comprises the following steps: mixing a titanium source, a first film-forming additive and ethanol to obtain a titanium source solution; mixing a lithium source, a second film-forming additive and ethanol to obtain a lithium source solution; adding graphite to ethanol to obtain an ethanol mixed solution of the graphite; simultaneously adding the obtained titanium source solution and the lithium source solution to the ethanol mixed solution of the graphite; carrying out a hybrid reaction at 20-50 DEG C until ethanol evaporates to dryness, so as to obtain coated precursor powder; and sintering the precursor powder at 700-900 DEG C for 4-8 hours, so as to obtain the Li4Ti5O12-coated graphite composite material LTO-G. According to the lithium titanate-coated graphite composite material prepared by the method, inorganic film-forming additives are added to a coating layer, so that the low-temperature performance and the initial charge-discharge efficiency of the material are improved.

Description

technical field [0001] The invention relates to a lithium titanate-coated graphite composite material and a preparation method thereof, belonging to the technical field of lithium-ion batteries. Background technique [0002] Lithium-ion battery has become the most widely used secondary battery due to its high energy density, good cycle performance and environmental friendliness, and its application fields are constantly expanding. With the continuous expansion of the application range of lithium-ion batteries, its shortcomings have gradually emerged, such as poor low-temperature performance, under low-temperature conditions, the discharge capacity is greatly affected, and the cycle performance is also sharply reduced, which cannot meet people's expectations for lithium-ion batteries. Requirements for use under low temperature conditions. [0003] Studies have found that at low temperatures, the transfer impedance of lithium ions increases. On the one hand, the mass transfer...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/485H01M4/62H01M10/0525H01M4/36
CPCH01M4/366H01M4/485H01M4/625H01M10/0525Y02E60/10
Inventor 程先桃
Owner RIGHTFUL TECH