Synthesis method for preparing high-cost-performance lithium iron phosphate precursor by controlling crystallization

A lithium iron phosphate and crystallization control technology, which is applied in the direction of phosphorus compounds, chemical instruments and methods, structural parts, etc., can solve the problems of difficult industrialization and high requirements for the control of production conditions of lithium iron phosphate, and achieve high batch stability and synthesis The method is simple and fast, and the effect of reducing production cost

Active Publication Date: 2021-06-11
四川优源新能源有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of this application is to overcome the problems in the prior art that the preparation of lithium iron phosphate by the liquid phase method has high requirements on the control of production conditions and is difficult to industrialize, and to provide a synthesis method for the preparation of cost-effective lithium iron phosphate precursor with simple production process and controlled crystallization

Method used

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  • Synthesis method for preparing high-cost-performance lithium iron phosphate precursor by controlling crystallization
  • Synthesis method for preparing high-cost-performance lithium iron phosphate precursor by controlling crystallization
  • Synthesis method for preparing high-cost-performance lithium iron phosphate precursor by controlling crystallization

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Embodiment 1

[0027] The present invention discloses a synthesis method for preparing a cost-effective lithium iron phosphate precursor by controlling crystallization. In this embodiment, lithium sulfate, ferrous sulfate, and monoammonium phosphate are used as raw materials, and sulfuric acid and sodium hydroxide are used as the pH adjustment method. Acid and base preparation of lithium iron phosphate precursor, see figure 1 , its specific preparation method is as follows:

[0028] S1) preparing lithium ion concentration with deionized water is 300L of lithium sulfate solution of 0.9mol / L, and sulfuric acid adjusts the pH value to be less than 4; It is 300L of ferrous sulfate solution of 0.3mol / L to prepare ferrous ion concentration with deionized water, and sulfuric acid to adjust the pH value to be less than 4; prepare 300L of monoammonium phosphate solution with a phosphate ion concentration of 0.3mol / L with deionized water, and adjust the pH value to be less than 4 with sulfuric acid; ...

Embodiment 2

[0034] In this example, lithium iron phosphate precursors were prepared using lithium chloride, ferrous chloride, and sodium phosphate as raw materials, and hydrochloric acid and ammonia water as acids and bases to adjust the pH value. The specific preparation method is as follows:

[0035] S1) preparing lithium ion concentration with deionized water is 300L of lithium chloride solution of 3mol / L, and hydrochloric acid regulates pH value to be less than 4; It is 300L of ferrous chloride solution of 3mol / L to prepare ferrous ion concentration with deionized water, and hydrochloric acid to adjust the pH value to be less than 4; prepare 300L of sodium phosphate solution with a phosphate ion concentration of 3mol / L with deionized water, and adjust the pH value to be less than 4 with hydrochloric acid;

[0036] In a 1000L reaction kettle, sequentially add lithium salt solution, ferrous salt solution, and phosphate solution, stir and mix evenly to obtain a mixed solution;

[0037] S...

Embodiment 3

[0041] In this example, lithium nitrate, ferrous nitrate, and sodium phosphate were used as raw materials, and nitric acid and sodium hydroxide were used as acids and bases to adjust the pH value to prepare lithium iron phosphate precursors. The specific preparation method is as follows:

[0042]S1) prepare 300L of lithium nitrate solutions with a concentration of lithium ions of 3mol / L with deionized water, and adjust the pH value with nitric acid to be less than 4; Adjust the pH value to be less than 4; prepare 300L of sodium phosphate solution with a phosphate ion concentration of 2mol / L with deionized water, and adjust the pH value to be less than 4 with nitric acid;

[0043] In a 1000L reaction kettle, sequentially add lithium salt solution, ferrous salt solution, and phosphate solution, stir and mix evenly to obtain a mixed solution;

[0044] S2) Slowly add sodium hydroxide to the reaction kettle until the pH value is 6.5, heat to 120° C., keep the reaction kettle sealed...

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Abstract

The invention discloses a synthesis method for preparing a high-cost-performance lithium iron phosphate precursor by controlling crystallization, and relates to the technical field of battery materials, and the synthesis method comprises the following steps: S1) preparing a mixed solution of lithium salt, ferrous salt and phosphate, wherein the pH value of the mixed solution is less than 4; s2) stirring the mixed solution obtained in the step S1) at room temperature, slowly adding alkali to adjust the pH value to 6-7, heating and pressurizing the solution to a set temperature and a set pressure, and carrying out heat and pressure preservation reaction for 1-6 hours; s3) filtering the liquid to obtain a solid precipitate, and washing and drying the liquid to obtain a lithium iron phosphate precursor, wherein the set temperature ranges from 80 DEG C to 120 DEG C and the set pressure ranges from normal pressure to 0.3 MPa. The synthesis method of the lithium iron phosphate precursor disclosed by the invention is simple and rapid, the reaction conditions are easy to control, and the method is convenient to popularize and apply and beneficial to industrial implementation.

Description

technical field [0001] The invention relates to the technical field of battery materials, in particular to a synthesis method for preparing a cost-effective lithium iron phosphate precursor by controlling crystallization. Background technique [0002] In 1997, Padhi et al. obtained LiFePO with a regular olivine structure. 4 , its theoretical capacity is as high as 170mAh / g, excellent charge-discharge cycle performance, low price, excellent high-temperature performance, environment-friendly and pollution-free, so LiFePO 4 It is considered to be a very ideal cathode material for ion batteries. At present, the production technology of lithium iron phosphate can be generally divided into two types: solid-phase method and liquid-phase method. The solid-phase method is currently the most widely used and most mature method for synthesizing lithium iron phosphate. The iron source used in the solid-phase synthesis method is generally iron oxide, iron phosphate, etc., the lithium so...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/30C01B25/45H01M4/58
CPCC01B25/30C01B25/45H01M4/5825C01P2004/03C01P2002/72C01P2004/62Y02E60/10
Inventor 喻国强
Owner 四川优源新能源有限公司
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