Composite LiFePO4/C cathode material for lithium ion battery and preparation method for composite LiFePO4/C cathode material

A composite cathode material, lithium-ion battery technology, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of poor processing performance, low conductivity, low density, etc., to eliminate voids and looseness, improve uniformity, Density-enhancing effect

Active Publication Date: 2015-01-28
四川浩普瑞新能源材料股份有限公司
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0005] In view of the defects of low density, low electrical conductivity and poor processability of lithium iron phosphate materials in the prior art, starting from the practical application of materials, the present invention provides a micron-sized LiFePO with an in-situ carbon conductive network. 4 The preparation method of the / C composite positive electrode material takes into account the electrochemical performance and processing performance of the lithium iron phosphate material, and according to the method of the present invention, a high-density, high-rate, high-capacity lithium-ion battery positive electrode material can be obtained

Method used

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  • Composite LiFePO4/C cathode material for lithium ion battery and preparation method for composite LiFePO4/C cathode material
  • Composite LiFePO4/C cathode material for lithium ion battery and preparation method for composite LiFePO4/C cathode material
  • Composite LiFePO4/C cathode material for lithium ion battery and preparation method for composite LiFePO4/C cathode material

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Effect test

Embodiment 1

[0035] Lithium carbonate, ferrous oxalate, and ammonium dihydrogen phosphate were weighed according to the Li:Fe:P molar ratio of 1.03:0.97:1.006. Firstly, ferrous oxalate, ammonium dihydrogen phosphate and glucose accounting for 5wt% of the mixed material were added to the oblique mixer, and the homogeneous mixture was heat-treated at 570° C. for 4 hours after oblique mixing ball milling for 4 hours to obtain a composite precursor. The obtained precursor was mixed with the weighed lithium carbonate and graphite oxide accounting for 3wt% of the mixed material by ball milling in an oblique mixer for 3 hours, and then pressed to form under a pressure of 12 MPa. Put the formed body in a pressure sintering furnace protected by a 0.7MPa nitrogen-hydrogen atmosphere, calcinate at 760°C for 2 hours, cool to room temperature, and obtain micron-sized LiFePO after crushing. 4 / C composite cathode material. The carbon content in the composite cathode material detected by a carbon-sulfur...

Embodiment 2

[0037] Lithium carbonate, iron phosphate dihydrate, and lithium phosphate were weighed according to the Li:Fe:P molar ratio of 1.02:0.98:1.004. First, ferric phosphate dihydrate and starch accounting for 6wt% of the mixed material were added into the oblique mixer, and the obtained homogeneous mixture was heat-treated at 550° C. for 2 h to obtain a composite precursor after an oblique-mix ball mill. The obtained precursor was mixed with weighed lithium carbonate, lithium phosphate and superconducting carbon black accounting for 2.0 wt% of the mixed material by ball milling in an oblique mixer for 5 hours, and then pressed to form under a pressure of 14 MPa. Put the molded body in an atmosphere furnace, calcinate at 700°C for 0.5h under the protection of 0.5MPa argon, cool to room temperature, and obtain LiFePO after crushing 4 / C composite cathode material. Detecting that the carbon content in the composite positive electrode material is 3.5wt%, the particle size observed und...

Embodiment 3

[0039] Lithium hydroxide monohydrate, ferric oxide, and diammonium hydrogen phosphate were weighed according to the Li:Fe:P molar ratio of 1.05:0.95:1.01. Firstly, ferric oxide, diammonium hydrogen phosphate and polypropylene accounting for 15wt% of the mixed material were added into the oblique mixer, and after oblique mixing ball milling for 4 hours, the obtained homogeneous mixture was heat-treated at 650° C. for 5 hours to obtain a composite precursor. The obtained composite precursor was mixed with weighed lithium hydroxide monohydrate and graphite oxide accounting for 1.5wt% of the mixed material by ball milling in an oblique mixer for 6 hours, and then pressed into shape under a pressure of 9 MPa. Put the molded body in a 0.6MPa atmosphere-protected pressure sintering furnace, calcinate at 720°C for 1h under the protection of argon-hydrogen, cool to room temperature, and obtain LiFePO after crushing. 4 / C composite cathode material. It is detected that the carbon conte...

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Abstract

The invention relates to a preparation method for a micron-sized composite LiFePO4 / C cathode material for a lithium ion battery. The method comprises the following steps of uniformly mixing an iron source, a phosphorus source and an organic carbon source, and pre-sintering the mixture to obtain a composite iron phosphate / carbon precursor; uniformly mixing the obtained composite precursor, a lithium source and an inorganic carbon source, performing compression molding, preserving heat for a certain time under 700 to 800 DEG C and certain inert gas pressure in a sintering furnace, and performing crushing to obtain the composite LiFePO4 / C cathode material after temperature reduction. The invention also relates to the micron-sized composite LiFePO4 / C cathode material obtained by the method and with a nano carbon conducting network. The material has the characteristics of high purity, high tap density, high consistency, high processability and high rate discharge performance.

Description

technical field [0001] The present invention relates to the preparation technology of positive electrode material for lithium ion batteries, in particular to a micron-sized LiFePO 4 The preparation method of / C composite cathode material and the LiFePO obtained by this method 4 / C composite cathode material. Background technique [0002] In the past few decades, with the increasing consumption of resources and the strengthening of environmental protection awareness, the global demand for new energy materials has increased year by year. Lithium battery materials have attracted widespread attention because of their high specific energy, environmental protection, safety, and repeatable charge and discharge. and R&D. After more than ten years of development, lithium-ion batteries are expected to become ideal energy storage devices for electric vehicles and hybrid vehicles. Therefore, lithium iron phosphate batteries with the advantages of high safety performance, excellent cy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58
CPCH01M4/364H01M4/5825H01M4/587Y02E60/10
Inventor 石迪辉周宏祥贺天江唐世国周少江方义
Owner 四川浩普瑞新能源材料股份有限公司
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