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A kind of natural graphite modification method for negative electrode material of lithium ion battery

A lithium-ion battery and natural graphite technology, applied in the field of lithium-ion battery material preparation, can solve problems such as low specific capacity, high platform voltage, and restrictions on the development of LTO, and achieve the effects of reducing decomposition reactions, improving stability, and reducing irreversible capacity

Active Publication Date: 2017-04-12
LUOYANG YUEXING NEW ENERGY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1) The platform voltage is too high, such as 1.55v ys Li+ / Li;
[0005] 2) The specific capacity is too low, the theoretical value is 175mAh / g
[0006] The above two shortcomings restrict the development of LTO in the field of lithium-ion batteries
[0007] The method of coating natural graphite with LTO / carbon nanotubes to make the prepared negative electrode material has high initial charge and discharge efficiency, high gram capacity and improved rate has not yet been reported.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Weigh 15 grams of Ti(OC 4 h 9 ) 4 and 15 g CH 3 COOLi·2H 2 O, mixing and stirring at low speed for 10 min, then adding 1.0 g of carbon nanotubes, and ultrasonically dispersing for 30 min; then adding 450 g of natural graphite and stirring at low speed for 10 min, and then adding 300 g of ethanol to form a sol-gel at 50 ° C; continue heating for 80 ℃ to volatilize the ethanol to obtain a gel; continue heating to 120 ℃ to evaporate all the ethanol to obtain a brown solid powder; dry at 150 ℃ for 8 hours to obtain a solid powder of the LTO precursor; put the solid powder of the LTO precursor in N 2 Under protection, the temperature was raised to 750° C. at a heating rate of 10° C. / min and sintered for 8 hours to obtain a negative electrode material coated with natural graphite by LTO nanospheres / carbon nanotubes.

Embodiment 2

[0027] Weigh 10 grams of Ti(OC 4 h 9 ) 4 and 20 g CH 3 COOLi·2H 2 O, mixed and stirred at low speed for 10 minutes, then added 2.0 grams of carbon nanotubes, and ultrasonically dispersed for 10 minutes; then added 400 grams of natural graphite and stirred at low speed for 10 minutes, and then added 400 grams of ethanol to form a sol-gel at 50 ° C; continue heating, Ethanol volatilizes to obtain a gel; continue heating until all the ethanol evaporates to obtain a brown solid powder; dry at 150 ° C for 8 hours to obtain a solid powder of the LTO precursor; put the solid powder of the LTO precursor in N 2 Under protection, the temperature was raised to 750° C. at a heating rate of 10° C. / min and sintered for 8 hours to obtain a negative electrode material coated with natural graphite by LTO nanospheres / carbon nanotubes.

Embodiment 3

[0029] Weigh 20 grams of Ti(OC 4 h 9 ) 4 and 10 g CH 3 COOLi·2H 2 O, mixed and stirred at low speed for 60 minutes, then added 0.5 grams of carbon nanotubes, and ultrasonically dispersed for 10 minutes; then added 500 grams of natural graphite and stirred at low speed for 10 minutes, and then added 250 grams of ethanol to form a sol-gel at 50 ° C; continue heating, Ethanol volatilizes to obtain a gel; continue heating until all the ethanol evaporates to obtain a brown solid powder; dry at 150 ° C for 8 hours to obtain a solid powder of the LTO precursor; put the solid powder of the LTO precursor in N 2 Under protection, the temperature was raised to 750° C. at a heating rate of 10° C. / min and sintered for 8 hours to obtain a negative electrode material coated with natural graphite by LTO nanospheres / carbon nanotubes.

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Abstract

A natural graphite modification method for a lithium ion battery negative electrode material comprises the following steps: taking Ti(OC4H9)4 and CH3COOLi.2H2O according to mass proportions, carrying out low speed stirring for 10min, adding carbon-nanotube, carrying out ultrasonic dispersion for 10-60min to obtain an LTO nanosphere / carbon nanotube, adding natural graphite, carrying out low speed stirring for 10min, adding ethanol to form sol-gel at 50DEG C, continuously heating on the basis of 50DEG C until ethanol is completely evaporated in order to obtain brown solid powder, drying the brown solid powder at 150DEG C for 8h to obtain LTO precursor solid powder, heating the LTO precursor solid powder under the protection of nitrogen according to a heating rate of 10DEG C / min until the temperature rises 750DEG C, and sintering for 8h to obtain the LTO nanosphere / carbon nanotube coated natural graphite negative electrode material. The method improves the electric conductivity and the structure stability of a natural graphite coating layer.

Description

technical field [0001] The invention belongs to the technical field of preparation of lithium ion battery materials, in particular to a natural graphite modification method for negative electrode materials of lithium ion batteries. Background technique [0002] Natural graphite has the advantages of high capacity, flat charge-discharge curve, and low cost. It is an ideal anode material for lithium-ion batteries. However, natural graphite has disadvantages such as low initial charge-discharge efficiency, poor cycle performance, and high selectivity to electrolytes. Due to the structural characteristics of natural graphite with anisotropic layered structure and weak van der Waals force between layers, the anisotropic layered structure determines that the passivation SEI film formed by natural graphite during the first lithium intercalation process is not dense, lacks elasticity, It cannot prevent the co-intercalation of solvated lithium ions, thus reducing the initial charge-d...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/587H01M4/62B82Y30/00B82Y40/00
CPCB82Y30/00B82Y40/00H01M4/587H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 徐军红陈和平
Owner LUOYANG YUEXING NEW ENERGY TECH
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