A method for preparing olivine-type lithium iron phosphate cathode material

A technology of lithium iron phosphate and positive electrode materials, which is applied in the direction of phosphate, phosphorus oxyacids, chemical instruments and methods, etc., can solve problems such as neglect, and achieve the effect of simple method and ensuring batch stability and consistency

Active Publication Date: 2020-02-07
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the industry pays attention to the impact of battery-grade anhydrous iron phosphate impurities, particle size and morphology on lithium iron phosphate, but the influence of iron phosphate crystal structure is often ignored

Method used

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  • A method for preparing olivine-type lithium iron phosphate cathode material
  • A method for preparing olivine-type lithium iron phosphate cathode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] The method for preparing the olivine-type lithium iron phosphate positive electrode material, its specific steps are as follows:

[0016] Step 1. At room temperature, weigh lithium carbonate, anhydrous iron phosphate and carbon source according to a certain molar ratio, add a certain amount of water ball mill and mix for 6 hours, wherein the solid content is 50%, and the molar ratio of Li / Fe / P is 1.02:1:1, anhydrous iron phosphate is iron phosphate with tripartite structure, and the carbon source is sucrose;

[0017] Step 2. After the ball-milled material is dried, it is sintered at 700° C. for 16 hours under a nitrogen atmosphere, and the sintered product is cooled to below 60° C. to obtain an olivine-type lithium iron phosphate positive electrode material.

[0018] figure 1 a is the XRD pattern of the olivine-type lithium iron phosphate cathode material prepared in this example, indicating that the prepared material is a single olivine-type phase and has good crystal...

Embodiment 2

[0020] The method for preparing the olivine-type lithium iron phosphate positive electrode material, its specific steps are as follows:

[0021] Step 1. At room temperature, weigh lithium carbonate, anhydrous iron phosphate and carbon source according to a certain molar ratio, add a certain amount of water ball mill and mix for 6 hours, wherein the solid content is 50%, and the molar ratio of Li / Fe / P is 1.02:1:1, anhydrous iron phosphate is a mixed phase of monoclinic structure iron phosphate and trigonal structure iron phosphate with a molar ratio of 0.5:0.5, and the carbon source is sucrose;

[0022] Step 2. After the ball-milled material is dried, it is sintered at 700° C. for 16 hours under a nitrogen atmosphere, and the sintered product is cooled to below 60° C. to obtain an olivine-type lithium iron phosphate positive electrode material.

[0023] figure 1 b is the XRD pattern of the olivine-type lithium iron phosphate positive electrode material prepared in this example...

Embodiment 3

[0025] The method for preparing the olivine-type lithium iron phosphate positive electrode material, its specific steps are as follows:

[0026] Step 1. At room temperature, weigh lithium carbonate, anhydrous iron phosphate and carbon source according to a certain molar ratio, add a certain amount of water ball mill and mix for 6 hours, wherein the solid content is 50%, and the molar ratio of Li / Fe / P is 1.02:1:1, anhydrous iron phosphate is a mixed phase of hexagonal structure iron phosphate and trigonal structure iron phosphate with a molar ratio of 0.5:0.5, and the carbon source is sucrose;

[0027] Step 2. After the ball-milled material is dried, it is sintered at 700° C. for 16 hours under a nitrogen atmosphere, and the sintered product is cooled to below 60° C. to obtain an olivine-type lithium iron phosphate positive electrode material.

[0028] figure 1 c is the XRD pattern of the olivine-type lithium iron phosphate positive electrode material prepared in this example,...

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Abstract

The invention relates to a method for preparing an olivine type lithium iron phosphate positive electrode material, and belongs to the technical field of lithium ion battery electrode materials. The method comprises the steps: at room temperature, adding water to lithium carbonate, anhydrous iron phosphate and a carbon source and carrying out ball milling mixing, wherein the solid content is 30-70%, the molar ratio of Li to Fe to P is x to 1 to 1, 1<=x<=1.05, anhydrous iron phosphate is a mixed phase of monoclinal structure iron phosphate and tripartite structure iron phosphate with the molarratio of y:(1-y) or a mixed phase of hexagonal structure iron phosphate and tripartite structure iron phosphate with the molar ratio of y:(1-y), and 0<=y<=0.8; and after the ball-milled material is dried, sintering in a nitrogen atmosphere to obtain the olivine type lithium iron phosphate positive electrode material. The invention provides the method comprising that anhydrous iron phosphate havingspecific crystal structure is used as a raw material for preparing lithium iron phosphate, so as to further optimize the synthesis and performance of LiFePO4.

Description

technical field [0001] The invention relates to a method for preparing an olivine-type lithium iron phosphate positive electrode material, belonging to the technical field of lithium ion battery electrode materials. Background technique [0002] As a cathode material for lithium-ion batteries, olivine-type phosphate material LiMPO 4 (M=Fe, Mn, Co, Ni) have received great attention since they were first reported in 1997. They have the advantages of wide source of raw materials, good stability and high safety, and have good application prospects. Lithium iron phosphate (LiFePO 4 ) has a 3.4 V voltage platform, which has been commercialized many years ago and is currently widely used in power and energy storage batteries. [0003] At present, the methods for industrial production of lithium iron phosphate are solid-phase method and hydrothermal method. Among them, the solid-phase method is simple and easy to implement, and is currently the main method for the production of li...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/525H01M4/58H01M10/0525C01B25/26C01B25/45C01B25/37
CPCC01B25/26C01B25/375C01B25/45H01M4/525H01M4/58H01M10/0525Y02E60/10
Inventor 方海升龚鄢武良
Owner KUNMING UNIV OF SCI & TECH
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