Method for preparing spherical LFP (lithium iron phosphate)/carbon doped composite powder

A lithium iron phosphate and carbon composite technology, used in electrical components, battery electrodes, circuits, etc., can solve the problems of large material particles, difficulty in obtaining high-purity cathode materials, uneven mixing, etc., to improve conductivity and consistency. , to ensure the effect of uniformity

Inactive Publication Date: 2011-05-04
LANZHOU JINCHUAN NEW MATERIAL SCI & TECH
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Problems solved by technology

However, it is difficult to obtain high-purity cathode materials due to the large particles and unev

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  • Method for preparing spherical LFP (lithium iron phosphate)/carbon doped composite powder
  • Method for preparing spherical LFP (lithium iron phosphate)/carbon doped composite powder
  • Method for preparing spherical LFP (lithium iron phosphate)/carbon doped composite powder

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preparation example Construction

[0024] A preparation method of a spherical doped lithium iron phosphate / carbon composite powder, the molecular formula of the spherical doped lithium iron phosphate / carbon composite powder is: Li 1-x m x Fe 1-y M' y PO 4 / C (M , M' represent dopant ions). Its preparation method comprises the following steps:

[0025] (1) Raw material preparation: Ferric nitrate nonahydrate, phosphoric acid, lithium carbonate, doped metal ion salts and carbon source are used as raw materials, according to Li 1-x m x Fe 1-y M' y PO 4 (M, M' represent doping ions, x=0-0.05, y=0-0.05) Weigh the above-mentioned raw materials; carbon source is weighed according to the total mass ratio of raw materials of 5%-30%.

[0026] (2) Solution preparation: Add ferric nitrate nonahydrate to deionized water to make a solution with an iron ion concentration of 0.5-2.0mol / L; add phosphoric acid to deionized water to make a solution with a mass concentration of 30-50%.

[0027] (3) Slurry preparation: fi...

Embodiment 1

[0033] 1212.0g ferric nitrate nonahydrate was made into a solution of 1.0mol / L, and 345.9g of phosphoric acid was made into a solution with a concentration of 50%. Add ferric nitrate solution and phosphoric acid solution into deionized water and stir for 4 hours, control system pH to 2.0 and temperature to 45° C. to obtain ferric phosphate suspension. Then, 110.7 g of lithium carbonate and 68.2 g of glucose were added to the suspension, and ground in a vertical stirring mill for 10 hours to obtain a mixed slurry. The mixed slurry was spray-dried with an inlet temperature of 180° C., an outlet temperature of 79° C., and a flow rate of the mixed slurry of 15 ml / min to obtain spherical precursor particles. Precursors in high-purity N 2 Calcined under air atmosphere, the temperature was first raised to 300 ° C for 5 hours, and then the temperature was raised to 750 ° C for 12 hours to obtain spherical LiFePO 4 / C composite powder.

[0034] The battery performance tests of the o...

Embodiment 2

[0036]1212.0g ferric nitrate nonahydrate was made into a solution of 1.0mol / L, and 345.9g of phosphoric acid was made into a solution with a concentration of 50%. Add ferric nitrate solution and phosphoric acid solution into deionized water and stir for 4 hours, control the pH value of the system to 2.0, and the temperature to 55° C. to obtain ferric phosphate suspension. Then, 108.9 g of lithium carbonate, 8.9 g of magnesium oxalate and 68.2 g of glucose were added to the suspension, and ground in a vertical stirring mill for 10 hours to obtain a mixed slurry. The mixed slurry was spray-dried, the inlet temperature was 180°C, the outlet temperature was 80°C, and the flow rate of the mixed slurry was 15ml / min to obtain spherical precursor particles (see the attached figure 1 ). The precursor was calcined in a high-purity nitrogen atmosphere, and the temperature was first raised to 300°C for 5 hours, and then heated to 750°C for 12 hours to obtain spherical magnesium-doped Li ...

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Abstract

The invention discloses a method for preparing spherical LFP (lithium iron phosphate)/carbon doped composite powder, which relates to a method for preparing spherical LFP (lithium iron phosphate) for lithium-electron anode materials. The method is characterized in that the spherical LFP (lithium iron phosphate)/carbon doped composite powder is prepared by using ferric nitrate nonahydrate, phosphorous acids, lithium carbonates, doping metal ion salts and carbon sources as raw materials through the steps of (1) adding deionized water into the ferric nitrate nonahydrate and the phosphoric acid, reacting the obtained mixture so as to prepare an iron phosphate suspension; (2) adding the lithium carbonates, the doped metal ion salts and the carbon sources into the prepared suspension, grinding the obtained mixture so as to obtain mixed stock; and (3) carrying out spray drying on the mixed stock so as to obtain a precursor, then calcinating the precursor in an inert atmosphere or a weak reduction atmosphere so as to obtain the spherical LFP (lithium iron phosphate)/carbon doped composite powder. The appearance of the spherical LFP (lithium iron phosphate)/carbon doped composite powder synthesized by using the method of the invention seems like a spheroid, the composite powder has LFP (lithium iron phosphate) materials with good electrochemical performance, and the process is simple, therefore, the composite powder is suitable for industrial mass production.

Description

technical field [0001] The invention discloses a method for preparing spherical doped lithium iron phosphate / carbon composite powder, and relates to a method for preparing spherical lithium iron phosphate used as a cathode material for lithium ion batteries. Background technique [0002] Lithium iron phosphate batteries have the advantages of rich raw materials, environmental friendliness, high potential and theoretical specific capacity, stable discharge voltage, good cycle performance, high safety and thermal stability, etc., and are considered to be the most likely to be widely used Lithium-ion power batteries have broad market prospects in fields such as electric vehicles and hybrid electric vehicles. However, the ionic conductivity and electronic conductivity of lithium iron phosphate are both low, which is only suitable for charging and discharging at low current density. The decrease in specific capacity during high-rate charging and discharging is a big problem in ba...

Claims

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Application Information

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IPC IPC(8): H01M4/1397
CPCY02E60/10
Inventor 闫忠强蒙延双朱用雷军鹏李德胜袁超群吴利军王宇陶冶朱再立吴静敬军臣
Owner LANZHOU JINCHUAN NEW MATERIAL SCI & TECH
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