A method for preparing an in-situ nitrogen-doped carbon-coated lithium iron phosphate- cathode material

A technology of carbon-coated lithium iron phosphate and positive electrode material is applied in the field of in-situ nitrogen-doped carbon-coated lithium iron phosphate positive electrode material and its preparation field, which can solve the problem of no research report on lithium iron phosphate positive electrode material, and achieve improved uniformity and The effect of charge-discharge rate performance

Active Publication Date: 2019-01-18
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0004] At present, there is no related research report on the use of in-situ dopi

Method used

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  • A method for preparing an in-situ nitrogen-doped carbon-coated lithium iron phosphate- cathode material
  • A method for preparing an in-situ nitrogen-doped carbon-coated lithium iron phosphate- cathode material

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Experimental program
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Effect test

Embodiment 1

[0019] (1) Put urea in a crucible, wrap it tightly with 3 layers of tinfoil paper, and sinter it in a tube furnace at 500°C for 5 hours, cool it down to room temperature naturally, and prepare a dispersion with a solid content of 45%. Ultrasonic stripping was then performed, and after rotary evaporation and freeze-drying, a layered g-C with a thickness of 50nm was obtained. 3 N 4 ;

[0020] (2) Weigh the g-C of step (1) according to the mass ratio of 120:92.4:1 3 N 4 , Py, and FePc were added to tetrahydrofuran solvent, and reacted at 60°C for 8 hours under the condition of avoiding light and darkness, and g-C was obtained after centrifugation and freeze-drying. 3 N 4 Axial complex g-C with iron phthalocyanine 3 N 4 -Py-FePc;

[0021] (3) According to the stoichiometric ratio Li:Fe:P:g-C 3 N 4 -Py-FePc=1:0.86:1:0.14, weigh lithium source, ferrous oxalate, phosphorus source and g-C 3 N 4 -Py-FePc, carried out ball milling dispersion treatment in ethanol or deionized ...

Embodiment 2

[0025] (1) Put the urea in the crucible, wrap it tightly with 2 layers of tinfoil paper in a sealed state, sinter in a tube furnace at 450°C for 4 hours, cool naturally to room temperature, and prepare a dispersion with a solid content of 40%. Ultrasonic stripping was then performed, and after rotary evaporation and freeze-drying, a layered g-C with a thickness of 60nm was obtained. 3 N 4 ;

[0026] (2) Weigh the g-C of step (1) according to the mass ratio of 120:92.4:1 3 N 4 , Py and FePc were added to the tetrahydrofuran solvent, and reacted at a constant temperature of 50°C for 6 hours under the condition of avoiding light and darkness, and g-C was obtained after centrifugation and freeze-drying. 3 N 4 Axial complex g-C with iron phthalocyanine 3 N 4 -Py-FePc;

[0027] (3) According to the stoichiometric ratio Li:Fe:P:g-C 3 N 4 -Py-FePc=1:0.92:1:0.08, weigh lithium source, ferrous oxalate, phosphorus source and g-C 3 N 4 -Py-FePc, ball-milling and dispersing in e...

Embodiment 3

[0031] (1) Put urea in a crucible, wrap it tightly with 5 layers of tinfoil paper in a sealed state, sinter in a tube furnace at 550°C for 6 hours, cool naturally to room temperature, and prepare a dispersion with a solid content of 50%. Ultrasonic stripping was carried out again, and after rotary evaporation and freeze-drying, a layered graphite phase carbon nitride powder (g-C) with a thickness of 80nm was obtained. 3 N 4);

[0032] (2) Weigh the g-C of step (1) according to the mass ratio of 120:92.4:1 3 N 4 , Py and FePc were added to the tetrahydrofuran solvent, and reacted at a constant temperature of 70°C for 9 hours under the condition of avoiding light and darkness, and g-C was obtained after centrifugation and freeze-drying. 3 N 4 Axial complex g-C with iron phthalocyanine 3 N 4 -Py-FePc;

[0033] (3) According to the stoichiometric ratio Li:Fe:P:g-C 3 N 4 -Py-FePc=1:0.8:1:0.2, weigh lithium source, ferrous oxalate, phosphorus source and g-C 3 N 4 -Py-FePc...

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Abstract

The invention provides a method for preparing an in-situ nitrogen-doped carbon-coated lithium iron phosphate cathode material. Namely, the graphite phase carbon nitride (g-C 3N 4) and iron phthalocyanine (FePc) are used as the main nitrogen source and carbon source, and part of the iron source is provided. In-situ nitrogen doping carbon coating is used to improve the uniformity of coating and theperformance of charge/discharge rate. The method mainly comprises the following steps: firstly, obtaining g- C3N 4 through a urea pyrolysis method, and then combining the g-C 3N 4 and the FePc in axial coordination manner through a carboxyl pyridine (Py) to obtain g-C3N4-Py-FePc;Using ethanol as dispersant, ball-milling and dispersing ferrous oxalate, lithium source, phosphorus source and complex,and then performing drying in vacuum. The in-situ nitrogen-doped lithium iron phosphate coated cathode material was prepared by sintering and pulverizing the dried material.

Description

technical field [0001] The invention relates to a lithium ion battery cathode material, in particular to an in-situ nitrogen-doped carbon-coated lithium iron phosphate cathode material and a preparation method thereof. Background technique [0002] With the continuous development of the automobile industry, the pollution caused by fuel emissions is becoming more and more serious. As a new energy battery, lithium batteries have attracted extensive attention from researchers. Among many cathode materials for lithium batteries, lithium iron phosphate (LiFePO 4 ) With its excellent cycle life and safety, it plays an important role in the cathode material of power vehicles. But LiFePO 4 The problems of low electrical conductivity and ion mobility in the actual use of the material limit its further application. In recent years, in order to improve LiFePO 4 The electrical properties of the material, the carbon coating method is considered to be an effective method for LiFePO 4...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCH01M4/366H01M4/5825H01M4/62H01M10/0525Y02E60/10
Inventor 陈霞刘兴亮程蒙汪伟伟万宁陈峰彭家兴
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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