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Preparation method of lithium titanate combined conductive agent of lithium ion battery cathode material

A composite conductive agent and lithium-ion battery technology, applied in electrode manufacturing, battery electrodes, circuits, etc., can solve the problems of large volume change, low electronic conductance and ion conductance, voltage hysteresis, etc., achieve large contact area and reduce polarization Effect

Inactive Publication Date: 2011-01-19
BEIJING JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the anode materials of lithium-ion batteries mostly use various lithium-intercalated carbon materials, but carbon materials still have some disadvantages as lithium-ion anode materials: the first charge and discharge efficiency is low; it is easy to chemically react with the electrolyte; there is obvious voltage hysteresis; The preparation method of carbon materials is relatively complicated; and, compared with carbon negative electrodes in lithium-ion batteries, alloy-type negative electrode materials generally have higher specific capacity, but repeated intercalation and extraction of lithium will lead to volume changes of alloy-type electrodes during charging and discharging. Larger, and gradually pulverized and failed, so the cycle performance is poor
[0009] However, since lithium-ion batteries use organic electrolytes, spinel-type lithium titanate Li 4 Ti 5 o 12 The material itself has the disadvantages of low electronic conductance and ion conductance, fast capacity decay and poor rate performance during high-current charging and discharging, which limit its application under high-current charging and discharging conditions.

Method used

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  • Preparation method of lithium titanate combined conductive agent of lithium ion battery cathode material
  • Preparation method of lithium titanate combined conductive agent of lithium ion battery cathode material
  • Preparation method of lithium titanate combined conductive agent of lithium ion battery cathode material

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Effect test

Embodiment 1

[0022] According to the lithium ion battery negative electrode material lithium titanate composite conductive agent preparation method of the present invention is as follows:

[0023] Put an appropriate amount of VGCF into the reaction vessel, then put the reaction vessel into the reaction furnace according to the procedure, pass in the inert gas Ar, heat to 150°C and maintain it for 10h, and pass in the fluoride F 2 2min, stop F 2 Pass in, cut off the power supply of the heating device, after the fluorinated product is cooled to room temperature, stop the inert gas Ar to feed in, take out the fluorinated material, and prepare the modified conductive material VGCF and acetylene black according to (0.5-3):(1 -3) The mass ratio is mixed into a composite conductive agent.

[0024] In this example, the prepared modified conductive material VGCF was mixed with acetylene black at a mass ratio of 1:2 to form a composite conductive agent. Using N-methyl-2-pyrrolidone as solvent, th...

Embodiment 2

[0028] Put an appropriate amount of VGCF into the reaction vessel, then put the reaction vessel into the reaction furnace according to the procedure, pass in the inert gas Ar, heat to 200 ° C and maintain it for 10 hours; pass the fluoride F 2 2min; stop F 2 After the fluorinated product is cooled to room temperature, stop the inert gas Ar, take out the fluorinated material, and mix it with acetylene black at a mass ratio of 1:2 to form a composite conductive agent.

[0029] Using N-methyl-2-pyrrolidone as solvent, the negative electrode material Li 4 Ti 5 o 12 Mix it with mixed conductive material and binder PVDF in a ratio of 6:2:2 and stir at high speed to make a slurry evenly, and apply the slurry evenly on the collector foam nickel; finally, place the wet electrode in a vacuum oven Dry at 120°C for 12 hours to make an electrode sheet.

[0030] The test results of the conventional lithium-ion battery negative electrode evaluation method show that the capacity and cycl...

Embodiment 3

[0032] Put an appropriate amount of VGCF into the reaction vessel, then put the reaction vessel into the reaction furnace according to the procedure, pass in the inert gas Ar, heat to 300 ° C and maintain it for 10 hours; pass the fluoride F 2 2min; stop F 2 After the fluorinated product is cooled to room temperature, stop the inert gas Ar, take out the fluorinated material, and mix it with acetylene black at a mass ratio of 1:2 to form a composite conductive agent.

[0033] Using N-methyl-2-pyrrolidone as solvent, the negative electrode material Li 4 Ti 5 o 12 Mix with mixed conductive material and binder PVDF according to the ratio of 6:2:2, stir at a high speed to make a slurry evenly, and apply the slurry evenly on the nickel foam of the current collector. The wet electrode was dried in a vacuum oven at 120° C. for 12 hours to make an electrode sheet.

[0034]The test results of the conventional lithium-ion battery negative electrode evaluation method show that the ca...

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Abstract

The invention provides a preparation method of lithium titanate combined conductive agent of lithium ion battery cathode material. Fluorinion is led into the surface of the existing conductive agent VGCF and has better consistency with active material and current collector by chemical reaction; modified conductive material VGCF after fluoridation is obtained, so that the invention can better perform the function of collecting micro current; the prepared modified conductive material VGCF is mixed with acetylene black according to certain mass ratio to prepare an electrode slice. According to the method of the invention, a favourable conductive network can form in the electrode, and the migration rate of the lithium ion in the electrode material can be effectively improved by matching the liner conductive agent VGCF with fluorinated surface with a granulous conductive agent acetylene black, so that the high-rate charge / discharge capacity of high cathode material Li4Ti5O12 can be improved.

Description

technical field [0001] The invention relates to the technical field of composite conductive agent for negative electrode materials of lithium ion batteries, in particular to a lithium ion battery negative electrode material Li 4 Ti 5 o 12 Modification method of the conductive agent used. Background technique [0002] Lithium-ion secondary batteries are favored by people for their excellent characteristics such as high voltage, high capacity, high cycle performance and high energy density, and are called the leading power source in the 21st century. In order to better meet the development needs of power batteries, the research on new positive and negative electrode materials with high performance and low cost is the key to the development of lithium-ion secondary batteries. [0003] At present, the anode materials of lithium-ion batteries mostly use various lithium-intercalated carbon materials, but carbon materials still have some disadvantages as lithium-ion anode materi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/04H01M4/62
CPCY02E60/12Y02E60/10
Inventor 康晓红
Owner BEIJING JIAOTONG UNIV