Method of preparing lithium iron phosphate having high conductivity and superior low temperature discharge property

A technology of lithium iron phosphate and high conductivity, which is applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of poor low-temperature discharge performance and low conductivity of lithium iron phosphate, and achieve strong high-current discharge capability and enhanced Effect of low temperature discharge performance and good low temperature performance

Inactive Publication Date: 2011-04-27
HANGZHOU LONGWEI ENERGY TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention mainly aims to provide a method for preparing lithium iron phosphate with high conductivity and good low-temperature discharge performance for the defects of low electrical conductivity and poor low-temperature discharge performance of lithium iron phosphate prepared by the current method.

Method used

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  • Method of preparing lithium iron phosphate having high conductivity and superior low temperature discharge property
  • Method of preparing lithium iron phosphate having high conductivity and superior low temperature discharge property
  • Method of preparing lithium iron phosphate having high conductivity and superior low temperature discharge property

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Ferrous sulfate solution with a molar concentration of iron salt of 0.1mol / L is mixed with phosphoric acid solution, the mixing condition is iron: phosphorus molar ratio 3:2.5, and then rapidly neutralized with ammonia water with a molar concentration of 0.1mol / L at a temperature of -20°C And, stir the solution during neutralization to speed up the neutralization speed, and obtain ultra-fine Fe in an instant 3 (PO 4 ) 2 ·xH 2 O precipitation, ultrafine Fe 3 (PO 4 ) 2 ·xH 2 O precipitate particle size D 50 At 4 μm, the Fe 3 (PO 4 ) 2 ·xH 2 The O precipitate was washed and dried under vacuum, then mixed with Fe at a molar ratio of 1:1:0.1 3 (PO 4 ) 2 ·xH 2 O, lithium phosphate, conductive agent, the conductive agent is sucrose, mixed evenly, and sintered at 550°C for 20 hours to obtain lithium iron phosphate material, the particle size of lithium phosphate used in sintering is D 50 at 1 μm.

Embodiment 2

[0030] Ferrous sulfate solution with a molar concentration of iron salt of 0.25mol / L is mixed with phosphoric acid solution, the mixing condition is iron:phosphorus molar ratio 3:2.4, and then rapidly neutralized with ammonia water with a molar concentration of 0.5mol / L at a temperature of -10°C And, stir the solution during neutralization to speed up the neutralization speed, and obtain ultra-fine Fe in an instant 3 (PO 4 ) 2 ·xH 2 O precipitation, ultrafine Fe 3 (PO 4 ) 2 ·xH 2 O precipitate particle size D 50 At 3 μm, the Fe 3 (PO 4 ) 2 ·xH 2 The O precipitate was vacuum-dried and then mixed with Fe at a molar ratio of 1:1:0.1 3 (PO 4 ) 2 ·xH 2 O, lithium phosphate, conductive agent, the conductive agent is glucose, mixed evenly, and sintered at 600°C for 10 hours to obtain lithium iron phosphate material, the particle size of lithium phosphate used in sintering is D 50 at 5 μm.

Embodiment 3

[0032] Ferrous sulfate solution with a molar concentration of iron salt of 0.5mol / L is mixed with phosphoric acid solution, the mixing condition is iron: phosphorus molar ratio 3:2.3, and then at a temperature of 0°C, the sodium hydroxide solution with a molar concentration of 1mol / L is rapidly Neutralize, stir the solution during neutralization to speed up the neutralization speed, and obtain ultra-fine Fe in an instant 3 (PO 4 ) 2 ·xH 2 O precipitation, ultrafine Fe 3 (PO 4 ) 2 ·xH 2 O precipitate particle size D 50 At 5 μm, the Fe 3 (PO 4 ) 2 ·xH 2 The O precipitate was vacuum-dried and then mixed with Fe at a molar ratio of 1:1:0.1 3 (PO 4 ) 2 ·xH 2 O, lithium phosphate, conductive agent, the conductive agent is sucrose, mixed evenly, and sintered at 650°C for 5 hours to obtain lithium iron phosphate material, the particle size of lithium phosphate used in sintering is D 50at 3 μm.

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Abstract

The invention relates to a preparation method of lithium iron phosphate, in particular to a preparation method of the lithium iron phosphate having high conductivity and good low-temperature discharge performance. The method mainly aims at solving the defects of low conductivity, poor low-temperature discharge performance and the like of the lithium iron phosphate prepared by the existing method and provides the preparation method of the lithium iron phosphate having high conductivity and good low-temperature discharge performance. The main technical proposal of the preparation method is as follows: a soluble ferrous iron salt solution is adopted for mixing with a phosphoric acid solution or a soluble phosphate solution, then alkali is used for neutralization to obtain a superfine Fe3(PO4)2.xH2O precipitate with particle D50 being 1-5[mu]m, and then the precipitate is mixed with lithium phosphate and a conductive agent for sintering at high temperature.

Description

technical field [0001] The invention relates to a preparation method of lithium iron phosphate, in particular to a preparation method of lithium iron phosphate with high electrical conductivity and good low-temperature discharge performance. Background technique [0002] LiFePO 4 It is the material of choice for future power batteries, but the ionic conductivity and electronic conductivity of this material are very low, which is difficult to meet the actual needs. The main reason is that the preparation process leads to the decline of material properties. At present, the preparation methods of lithium iron phosphate mainly include the following types. [0003] The publication number is CN1581537, a mechanical solid-phase synthesis method of lithium iron phosphate, a positive electrode material for lithium ion batteries. The ratio is mixed evenly, placed in a ball mill container filled with an inert atmosphere, and ball milled for 18-36 hours; the obtained ball mill produc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/45
Inventor 吴雪峰骆宏钧蒋宝锡王胜奇
Owner HANGZHOU LONGWEI ENERGY TECH
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