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Preparation method of carbon-coated lithium iron phosphate composite material and carbon-coated lithium iron phosphate composite material

A technology of carbon-coated lithium iron phosphate and composite materials, which is applied to structural parts, electrical components, battery electrodes, etc., can solve the problem of uneven coating on the surface of lithium iron phosphate, reduce the electrochemical performance of lithium iron phosphate Coverage is difficult to control and other issues

Active Publication Date: 2021-06-08
SHENHUA ZHUNNENG RESOURCE COMPREHENSIVE DEV COMPANY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, the conventional method of coating carbon with lithium iron phosphate is to directly mix the carbon source with lithium iron phosphate and then treat it at high temperature. The advantage of this method is that it is suitable for large-scale industrial production. The disadvantage is that the coating degree of the surface of lithium iron phosphate is not uniform. , and the coating amount of carbon is not easy to control
This deficiency will reduce the electrochemical performance (such as capacity density, rate performance, etc.) of lithium iron phosphate material

Method used

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  • Preparation method of carbon-coated lithium iron phosphate composite material and carbon-coated lithium iron phosphate composite material
  • Preparation method of carbon-coated lithium iron phosphate composite material and carbon-coated lithium iron phosphate composite material
  • Preparation method of carbon-coated lithium iron phosphate composite material and carbon-coated lithium iron phosphate composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0067] Example 1 (S1)

[0068] Follow the steps below to prepare a carbon-covered phosphate composite material:

[0069] (1) 4.4621 g of lithium chloride (lithium source), 16.2204 g of iron chloride (iron source), 9.7994 g of phosphoric acid (phosphorus source) is mixed into ethanol (solvent) to obtain a mixed liquid; mixed liquid at 65 ° C The mixture is stirred in a water bath to obtain a wet gel; the wet gel is vacuum drying at 65 ° C for 12 h, resulting in a dry gel; the dry gel is ground to obtain a dry gel fine powder, i.e., lithium iron phosphate precursor The molar ratio of lithium source, iron source and phosphorus source is about 1: 0.95: 0.95;

[0070] (2) A argon atmosphere (inert atmosphere) at a flow rate of 1 ml / min (carbon source), and then the dry gel fine powder obtained by step (1) is placed in the upper wind with sucrose (carbon sources) In an argon atmosphere (an inert atmosphere), a high temperature heat treatment was carried out at 600 ° C for 12 h, cooled...

Embodiment 2-10

[0080] Example 2-10 (S2-10)

[0081] According to the method of Example 1, the carbon content of the carbon coated phosphate composite compound A2-A10 and detected the carbon content therefrom, and the materials used in Examples 1-10 were shown in Table 1, and the conditions in Examples 1-10 and The resulting carbon coated phosphate is shown in Table 2.

[0082] Table 1 Embodiment 1-10

[0083]

[0084]

[0085] Table 2: Conditions of each step in Examples 1-10 and the resulting carbon coated phosphate composite material

[0086]

[0087] result

[0088] The thickness of the carbon content and carbon cladding layer in the obtained carbon coated phosphate composite A2-10 is detected;

[0089]According to the method of Example 1, the resulting carbon coated phosphate composite material A2-A10 and metal lithium were assembled to test 2025 battery B2-B10, and the discharge test was performed under different conditions, and recorded its first and 2000 times. Discharge capacity de...

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Abstract

The invention relates to a preparation method of a carbon-coated lithium iron phosphate composite material and the carbon-coated lithium iron phosphate composite material prepared by the preparation method. The preparation method comprises the steps of preparing a lithium iron phosphate precursor from a lithium source, an iron source and a phosphorus source, and then carrying out high-temperature heat treatment on the lithium iron phosphate precursor in an inert atmosphere with a carbon source in a windward place, wherein the carbon source is an organic matter. The preparation method is simple and easy to implement, reduction and carbon coating are completed at a time, the carbon coating amount is low and controllable, and coating is uniform. The obtained carbon-coated lithium iron phosphate composite material has a thin and uniform carbon coating layer, can be used for assembling a lithium ion battery, and can maintain the electrochemical performance, such as capacity density and rate capability, of the lithium ion battery when being used in the lithium ion battery.

Description

Technical field [0001] The present invention belongs to the field of electrochemical energy materials, and more particularly to the preparation method of carbon-covered phosphate composites and carbon-covered phosphate composite composite. Background technique [0002] The pure phase of lithium iron phosphate has an insufficient electron conductivity, which cannot be directly used as an electrode material for the battery, and needs to be coated modified. Lithium iron phosphate surface coated is a proper amount of carbon is currently mainstream. Carbon materials have good electron conductivity, chemical and electrochemical stability, low density, high mechanical strength, and low content of 0.5 to 2% by weight, the electron conductivity of the iron-lithium electrode material can be significantly improved. [0003] There are 3 o'clock in the coated carbon layer. 1) Prevent lithium iron phosphate surfaces from erosion and oxidation of hydrogen fluoride. Lithium iron phosphate batter...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/58H01M4/583H01M10/0525
CPCH01M4/366H01M4/5825H01M4/583H01M10/0525Y02E60/10
Inventor 张云峰苗家兵范瑞成常宁高进李世春贾秀丽陈东
Owner SHENHUA ZHUNNENG RESOURCE COMPREHENSIVE DEV COMPANY