Lithium iron phosphate positive electrode material as well as preparation method and application thereof

A technology for lithium iron phosphate and positive electrode materials, applied in the direction of positive electrodes, battery electrodes, active material electrodes, etc., to achieve the effects of improving diffusion capacity, improving electrical conductivity, and excellent electrochemical performance

Pending Publication Date: 2021-10-26
SUNWODA ELECTRIC VEHICLE BATTERY CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The main purpose of the present invention is to provide a lithium iron phosphate positive electrode material, its preparation method and application, so as to solve the shortcomings of lithium iron phosphate in the prior art in terms of capacity, life, safety, etc.

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  • Lithium iron phosphate positive electrode material as well as preparation method and application thereof
  • Lithium iron phosphate positive electrode material as well as preparation method and application thereof
  • Lithium iron phosphate positive electrode material as well as preparation method and application thereof

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preparation example Construction

[0028] According to another aspect of the present invention, there is also provided a method for preparing a lithium iron phosphate positive electrode material, which includes the following steps: preparing a mixed solvent of water and an organic solvent, adding a binary solution, a complexing agent solution and an acid solution therein , carry out the first stage reaction under the condition of pH value 1.8~2.4, form the intermediate reaction solution; adjust the pH value of the intermediate reaction solution to 2.6~3.2, carry out the second stage reaction, form Fe 3(PO 4 ) 2 Precursor; Wherein binary solution is the solution of soluble ferrous salt and phosphate ion-containing soluble compound; Fe 3 (PO 4 ) 2 Precursor dispersed to Li 3 PO 4 Nucleation growth in the crystal solution to obtain LiFePO 4 Precursor; LiFePO 4 The precursor and the carbon source are mixed, and then calcined under an inert atmosphere to obtain the lithium iron phosphate cathode material.

...

Embodiment 1

[0048] 1. Configure FeCl 2 and (NH 4 ) 2 HPO 4 binary aqueous solution, the total concentration of solute is 2mol / L, Fe 2+ with PO 4 3+ The mol ratio is 3:2; Citric acid aqueous solution is as complexing agent solution, and its molar concentration is 3mol / L; Carbonic acid aqueous solution is as acid solution, and its molar concentration is 0.2mol / L;

[0049] 2. Configure a mixed solvent of ethylene glycol and deionized water as the reaction solution, wherein the volume ratio of deionized water and ethylene glycol is 3:1, and at the same time add the above binary aqueous solution, citric acid aqueous solution and carbonic acid aqueous solution to the reaction solution , to carry out the reaction of stage 1 and stage 2, and continuously bubble high-purity N during the reaction process 2 to remove oxygen from the solution. Wherein, the add-on of binary solution is 85% of reaction solution volume, and the add-on of complexing agent solution is 15% of reaction solution volum...

Embodiment 2

[0056] 1. Configure FeSO 4 and NH 4 h 2 PO 4 binary aqueous solution, the total concentration of solute is 1.5mol / L, Fe 2+ with PO 4 3+ The mol ratio is 3.15:2; Aqueous oxalic acid is used as complexing agent solution, and its molar concentration is 5mol / L; Aqueous acetic acid is used as acid solution, and its molar concentration is 0.2mol / L;

[0057] 2. Configure the mixed solvent of polyethylene glycol 200 and deionized water as the reaction liquid, wherein the volume ratio of deionized water and polyethylene glycol is 2:1, and add the above-mentioned binary aqueous solution, oxalic acid aqueous solution and acetic acid aqueous solution to In the reaction solution, the reaction of stage 1 and stage 2 is carried out, and high-purity N is constantly bubbled in during the reaction 2 to remove oxygen from the solution. Wherein, the add-on of binary solution is 85% of reaction solution volume, and the add-on of complexing agent solution is 15% of reaction solution volume, ...

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Abstract

The invention provides a lithium iron phosphate positive electrode material as well as a preparation method and application thereof. The lithium iron phosphate positive electrode material comprises spherical lithium iron phosphate and carbon compounded on the surface of the spherical lithium iron phosphate, the spherical lithium iron phosphate is provided with an inner core and a surface layer located on the periphery of the inner core, the surface layer is coated with the carbon, and the porosity of the inner core is larger than that of the surface layer. The lithium iron phosphate positive electrode material provided by the invention has good dynamic performance (rate capability) and discharge gram capacity after being applied to the lithium ion battery, has excellent electrochemical performance, and has outstanding performance in the aspects of capacity, service life and safety.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium iron phosphate positive electrode material, a preparation method and application thereof. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) is currently one of the most successful commercialized cathode materials in the field of lithium-ion batteries due to its high safety performance and considerable electrochemical performance. However, its disadvantages such as low energy density, poor kinetic performance and lithium ion diffusion ability limit the commercial development and process of lithium iron phosphate. Cathode material is an important part of lithium-ion batteries, which is related to the capacity, life, cost and safety of lithium-ion batteries. Therefore, it is of great practical significance to develop lithium iron phosphate cathode materials with high reversible discharge capacity, excellent cycle performance and high thermal ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/58H01M4/136H01M10/0525
CPCH01M4/625H01M4/5825H01M4/136H01M10/0525H01M2004/028H01M2004/021Y02E60/10
Inventor 朱计划陈巍张耀
Owner SUNWODA ELECTRIC VEHICLE BATTERY CO LTD
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