Method for preparing ferrous phosphate-based lithium salt

A ferrous phosphate, lithium iron phosphate technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of uneven dispersion of conductive agents, affecting the conductivity of positive active materials, etc., to achieve low production costs, The synthesis process is simple and easy, and the effect of high yield

Inactive Publication Date: 2013-02-06
IRICO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when using the solid-phase method, it is difficult to mix various solid components fully, so the various components in the obtained lithium iron phosphate positive electrode active material, especially the conductive agent, are not uniformly dispersed, which directly affects the conductivity of the positive electrode active material.

Method used

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  • Method for preparing ferrous phosphate-based lithium salt
  • Method for preparing ferrous phosphate-based lithium salt
  • Method for preparing ferrous phosphate-based lithium salt

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Use an analytical balance to accurately weigh (NH 4 ) 3 PO 4 149g, FeCl 2 126.9g of LiF and 78g of LiF were respectively dissolved in 500ml of water, and the mechanical stirring speed was set to 300r / min for full dissolution and mixing. After stirring for 20 minutes, the raw materials were completely dissolved without visually visible crystal particles. At this time, under the action of the mechanical stirring paddle (speed = 400 rpm), the (NH 4 ) 3 PO 4 Pour the two prepared solutions with LiF into a large round bottom flask, stir for 30min, and then add FeCl 2 At the same time, 1500ml of dimethyl sulfoxide was added, 6.54g of sodium sulfite was added as an antioxidant, and the concentration of 1mol / L lithium hydroxide was added to adjust the Ph=6.5 of the solution. Use an oil bath (this example uses silicone oil) to heat at 104°C for 2 hours, and while heating, use a mechanical stirrer (rotational speed = 400 rpm) to stir. After completion, filter and wash the ...

Embodiment 2

[0045] Use an analytical balance to accurately weigh H 3 PO 4 9.8g, FeSO 4 15.2g of LiOH and 7.2g of LiOH were respectively dissolved in 50ml of water, and the mechanical stirring speed was set to 200r / min to stir for full dissolution and mixing. When the drug is completely dissolved, no visible crystal particles can be seen visually. At this time, under the action of the mechanical stirring paddle (speed = 300 rpm), the H 3 PO 4 Pour the two prepared solutions with LiOH into a large round bottom flask, stir for 30min, and then add FeSO 4 At the same time, 150ml of dimethyl sulfoxide was added, and 0.65g of sodium sulfite was added as an antioxidant, and the pH of the solution was adjusted to 7 by using 30% ammonia water. Use an oil bath (silicon oil is used in this laboratory) to heat at 110°C for 4 hours, while heating, use a mechanical stirrer (speed = 300 rpm) to stir simultaneously, filter and wash the solid at the bottom of the flask 4 times, and finally get Precur...

Embodiment 3

[0051] Use an analytical balance to accurately weigh H 3 PO 4 9.8g, FeSO 4 15.2g of LiOH and 7.2g of LiOH were respectively dissolved in 50ml of water, and the mechanical stirring speed was set to 500r / min for full dissolution and mixing. When the drug is completely dissolved, no visible crystal particles can be seen visually. At this time, under the action of the mechanical stirring paddle (speed = 400 rpm), the H 3 PO 4 Pour the two prepared solutions with LiOH into a large round bottom flask, stir for 30min, and then add FeSO 4 , while adding isophorone 150ml, adding sodium sulfite 0.65g as an antioxidant, and adjusting the pH of the solution to 6.8 with a concentration of 15% ammonia water. Use an oil bath (silicon oil is used in this laboratory) to heat at 140°C for 10 hours, while heating, use a mechanical stirrer (speed = 600 rpm) to stir simultaneously, and repeatedly wash and filter the solid at the bottom of the flask to finally get Precursor.

[0052] The fil...

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Abstract

The invention relates to a method for preparing a lithium iron phosphate material through a solvothermal method, in particular to a method for preparing a ferrous phosphate-based lithium salt. The method is characterized by comprising the following steps of: (1) preparing primary nano-grade lithium iron phosphate particles; (2) atomizing to form secondary particles; and (3) sintering lithium iron phosphate: sintering the obtained secondary lithium iron phosphate particles, baking in a nitrogen atmosphere or a mixed atmosphere of nitrogen and hydrogen in the volume ratio of (1-5):(95-99) at the high temperature of 400-800 DEG C for 6-25 hours, and cooling. The method for preparing the ferrous phosphate-based lithium salt provided by the invention has the advantages of rich raw material source, low price, simple and practicable synthesizing process, safety, reliability, low production cost, high yield and freeness from environmental pollution; and a product has high electrochemical performance. A high-boiling-point solvent is adopted partially instead of water, so that preparation of nano-grade lithium iron phosphate through a normal-pressure low-temperature hydrothermal method is realized.

Description

technical field [0001] The invention relates to the preparation of lithium iron phosphate material by a solvothermal method, in particular to a method for preparing ferrous phosphate-based lithium salt. Background technique [0002] In the prior art, the positive electrode active material LiFePO is generally prepared by solid phase method or wet chemical method. 4 , such as Chinese patent CN 1401559A discloses a lithium iron phosphate (LiFePO 4 ) preparation method, in which lithium salt, ferrous salt and phosphate are ground and mixed evenly, then calcined at a high temperature, and after the calcining is completed, a conductive agent is added to grind and mix to obtain lithium iron phosphate. However, when using the solid-phase method, it is difficult to mix various solid components fully, so various components in the obtained lithium iron phosphate positive electrode active material, especially the conductive agent, are unevenly dispersed, which directly affects the cond...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45B82Y40/00H01M4/58
CPCY02E60/12Y02E60/10
Inventor 刘涛涛
Owner IRICO
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