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Method for preparing lithium iron phosphate/nanometer carbon composite anode material

A composite positive electrode material, lithium iron phosphate technology, applied in the direction of electrode manufacturing, battery electrodes, electrical components, etc., can solve the problems of carbon nanotube agglomeration increasing the amount of raw materials, difficulty in fully dispersing carbon nanotubes, and reducing the capacity of composite materials, etc. , to improve the reversible discharge capacity, prevent agglomeration, and improve the ion conductivity

Inactive Publication Date: 2009-09-16
CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Lithium-ion battery slurry has very high solid content and high viscosity. It is difficult to fully disperse carbon nanotubes by this method
Therefore, the current method of using carbon nanotubes cannot give full play to its advantages. At the same time, due to the serious agglomeration of carbon nanotubes, the amount of raw materials has to be increased, which increases the cost and reduces the capacity of the composite material.

Method used

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  • Method for preparing lithium iron phosphate/nanometer carbon composite anode material
  • Method for preparing lithium iron phosphate/nanometer carbon composite anode material
  • Method for preparing lithium iron phosphate/nanometer carbon composite anode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039]Weigh 3 grams of nickel powder, 37 grams of lithium carbonate, 173 grams of ferrous oxalate, and 116 grams of ammonium dihydrogen phosphate, and use absolute ethanol as a dispersant to ball mill in a ball mill for 6 hours; the mixed precursor is vacuum dried at 50°C 12 Hours; the precursor is put into the tube furnace, vacuumed, and then high-purity nitrogen (N 2 Purity ≥99.999%), the nitrogen flow rate is 100sccm, and the temperature is increased to 750°C at a rate of 20°C / min; when the temperature rises to 750°C, the LPG is introduced and the nitrogen is turned off at the same time. The LPG flow is 100sccm. The carbon nanotubes were grown at the above temperature at a constant temperature for 60 minutes; the nitrogen flow was restored while the carbon source gas was turned off, and the nickel-doped lithium iron phosphate was prepared at a constant temperature of 750°C for 24 hours. Then, it is naturally cooled to room temperature under the protection of nitrogen atmosphere...

Embodiment 2

[0042] The liquefied petroleum gas in Example 1 was replaced with ethylene, and the main components of the prepared composite material were nickel-doped lithium iron phosphate and carbon nanotubes, the mass percentage of nickel-doped lithium iron phosphate was 92%, and the mass percentage of carbon nanotubes was 8%. The mixing, heating, constant temperature, electrode production, battery assembly and test conditions are the same as those in Example 1. The discharge capacity is 145mAh·g at 1C rate -1 , Reaching 95% of 0.2C discharge rate. See figure 2 As can be seen from the electron microscope photos, a large number of carbon nanotubes grow around the lithium iron phosphate, and there is no agglomeration of carbon nanotubes. It shows that the lithium iron phosphate / carbon nanotube composite cathode material can be successfully prepared under this condition, and the prepared carbon nanotubes are uniformly dispersed around the lithium iron phosphate particles, forming a lithium iro...

Embodiment 3

[0044] The liquefied petroleum gas in Example 1 was replaced with methane, and the protective atmosphere nitrogen was replaced with argon. The main components of the prepared composite material are nickel-doped lithium iron phosphate and carbon nanotubes, the mass percentage of nickel-doped lithium iron phosphate is 97%, and the mass percentage of carbon nanotubes is 3%. The mixing, heating, constant temperature, electrode production, battery assembly and test conditions are the same as those in Example 1. The discharge capacity is 130mAh·g at 1C rate -1 , Reaching 92% of 0.2C discharge rate. See image 3 As can be seen from the electron microscope photos, a large number of carbon fibers grow around the lithium iron phosphate, and there is no agglomeration of carbon fibers. It shows that the lithium iron phosphate / carbon fiber composite cathode material can be successfully prepared under this condition, and the prepared carbon fibers are evenly dispersed around the lithium iron ph...

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Abstract

The invention provides a method for preparing lithium iron phosphate / nanometer carbon composite anode material, which is characterized by comprising the steps as follows: 1) a precursor is pretreated, raw materials are weighed according to the components and weight percentage as follows: 0.2%-15% of catalyst, 5%-15% of lithium salt, 40%-60% of iron salt and 25%-45% of phosphate; the catalyst is one or several kinds of metal Fe, Co and Ni; the raw materials are added with dispersant and then are ball-milled in a ball grinder to prepare the precursor; 2) a carbon nano tube or carbon fiber grows; and 3) lithium iron phosphate or adulterant lithium iron phosphate is prepared. The invention solves the problem that the carbon nano tube is difficult to be dispersed in high-viscosity high-solid lithium iron phosphate slurry, and the invention provides the method for growing the carbon nano tube or the carbon fiber synchronously during the process of preparing the lithium iron phosphate and improves the specific capacity and the cycle life of the lithium iron phosphate under the condition of charging and discharging.

Description

Technical field [0001] The invention belongs to the field of lithium ion battery composite electrode materials, and relates to a preparation method of lithium iron phosphate / nano carbon composite positive electrode material. Background technique [0002] Lithium cobalt oxide as a cathode material for lithium-ion batteries has shown excellent performance in portable electronic products such as mobile phones, camcorders, notebook computers, digital cameras, media players, etc. However, it is easy to release oxygen at higher temperatures. Serious safety hazards. Now the scientific and industrial circles generally believe that lithium cobalt oxide is not suitable as a cathode material for high-power and high-capacity lithium-ion batteries for electric vehicles. At the same time, due to the high price of lithium cobalt oxide, lead-acid batteries have overwhelmingly occupied most of the market for many years. Therefore, looking for low-cost, high-performance cathode materials is the ne...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/58H01M4/62
CPCY02E60/12Y02E60/10
Inventor 陈召勇朱华丽
Owner CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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