Preparation method of ferrous lithium phosphate cathode composite material

A technology of lithium ferrous phosphate and composite materials, which is applied in the direction of electrode manufacturing, phosphorus compounds, chemical instruments and methods, etc., can solve the problems of high raw material cost, low discharge capacity and difficult diffusion of lithium ferrous phosphate, and achieve optimal capacity and Rate performance, guaranteed electrochemical performance, good particle rate performance

Active Publication Date: 2009-09-09
JIANGXI SHENGHUA NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the production of lithium ferrous phosphate, ferrous iron and ferric iron are mostly used as iron sources. Lithium ferrous phosphate made from ferrous iron sources has good electrochemical performance, but the tap density is low, and ferrous iron sources such as oxalate The iron content of iron, ferrous acetate, etc. is low, and the cost of raw materials is high; the discharge capacity of lithium ferrous phosphate made from ferric iron source is low, mainly because the mass of iron ions is large and difficult to diffuse, so that the surface and internal iron of the particles The concentration difference of ferrous salt is large, which affects its capacity, but the advantage is that the tap density is higher, and the material cost is about half lower than that of ferrous salt.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0010] Example 1: Take 20kg of ferric oxide and add it to an ultrafine ball mill for 2 hours to make the particle size reach 100-500nm, then add 9.25kg of lithium carbonate, 28.75kg of dihydrogen phosphate, 0.4kg of titanium dioxide, 1.6kg of carbon black, Add 50kg of acetone as dispersant and ball mill for 3 hours, then dry it in a vacuum dryer for 3-6 hours to dry the material into red pellets. Then put the pellets into a nitrogen-protected atmosphere furnace and heat and sinter at 550°C for 10 After hours, the gray-black lithium iron phosphate is obtained, and then it is put into the ball mill and crushed for 1 hour, and then 4kg glucose and 40kg acetone dispersant are added for ball milling for 2 hours, and then dried in a vacuum dryer for 3-6 hours to form small balls , Then put it into a nitrogen-protected atmosphere furnace and sinter at 780°C for 12 hours to obtain a lithium iron phosphate cathode composite material. Finally, mechanical crushing, mechanical crushing, and c...

example 2

[0012] Example 2: Take 20kg of ferric oxide into an ultrafine ball mill and ball mill for 2 hours to achieve a particle size of 100-500nm, then add 26kg of lithium dihydrogen phosphate, 0.4kg of titanium dioxide and 1.6kg of carbon black, and then add 50kg of acetone dispersant Ball mill for 3 hours, dry in a vacuum dryer for 3-6 hours, and then put the red pellets into a nitrogen-protected atmosphere furnace at 550°C for 10 hours to heat and sinter to obtain gray-black lithium iron phosphate. Lithium iron is fed into the ball mill to be crushed for 1 hour, then 4kg glucose and 40kg acetone are added to the ball mill for 2 hours, then put into a vacuum dryer and dried for 3-6 hours to make into small balls, and then put into a nitrogen-protected atmosphere furnace and sintered at 780℃ After 12 hours, the final mechanical crushing, mechanical crushing, and classification operations are carried out to obtain the final lithium iron phosphate cathode composite product.

[0013] After ...

example 3

[0014] Example 3: Take 37.8kg of iron phosphate into an ultrafine ball mill and ball mill for 2 hours, then add 9.25kg of lithium carbonate, 0.4kg of titanium dioxide and 1.6kg of carbon black, and then add 50kg of acetone for ball milling for 3 hours, and place the resulting material in a vacuum dryer Drying for 3 to 6 hours; the resulting white pellets are then put into a nitrogen-protected atmosphere furnace and kept at 550°C for 10 hours to heat and sinter to obtain gray-black lithium iron phosphate (LiFePO) 4 ) Material, crush the gray-black lithium iron phosphate material in a ball mill for 1 hour, then add 4kg glucose and 40kg acetone and ball mill for 2 hours, then dry it in a vacuum dryer for 3-6 hours to make into small balls, and then put in nitrogen protection Sintered in an atmosphere furnace at 780°C for 12 hours, and finally performed mechanical crushing, mechanical crushing, and classification operations to obtain the final lithium iron phosphate cathode composite ...

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Abstract

The invention relates to a preparation method of a ferrous lithium phosphate cathode composite material. The method comprises the following steps: stocking a ferric iron-source compound, a lithium-source compound, phosphate, doped tantalum compounds and carbon black according to a certain proportion; firstly adding the ferric iron-source compound into an ultrafine ball mill so as to have the grain diameter of 100 nm to 500 nm by ball milling; then, adding other raw materials and using acetone as a dispersant for ball milling and mixing, drying in vacuum and sintering at a low temperature in an inert protective atmosphere oven to deacidize ferric iron; afterwards, adding a certain amount of conductive agent material to obtain ferrous lithium phosphate, ball milling, mixing and drying and sintering at a high temperature in the inert protective atmosphere oven; and finally, shattering, crushing and elutriating to obtain the ferrous lithium phosphate cathode composite material. The invention has the advantages that the materials ensure the tap density and can achieve favorable capacity and magnification performance, and secondary sintering enables the carbon coating to be more even and the granular magnification to be better.

Description

Technical field [0001] The invention relates to a method for preparing a lithium iron phosphate positive electrode composite material. Background technique [0002] Since the advent of lithium ion secondary batteries in the 1990s, they have developed rapidly due to their irreplaceable advantages. Cathode material is the main component of lithium ion secondary battery, the material currently mainly includes LiCoO 2 , LiMn 2 O 4 And LiFePO, which is currently a research hotspot 4 material. LiCoO 2 Due to its insufficient high-temperature safety performance and the scarcity of metal cobalt, it is restricted in the application of high-power and large-capacity power batteries; LiMn 2 O 4 Due to its poor high-temperature cycle performance and safety performance, it is also insufficient in application; LiFePO 4 (Lithium iron phosphate) has become one of the most promising cathode materials due to its advantages such as good cycle performance, moderate voltage platform, stable discharge,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/58H01M4/62C01B25/45
CPCY02E60/12Y02E60/10
Inventor 彭澎
Owner JIANGXI SHENGHUA NEW MATERIAL CO LTD
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