C3N4-carbon-coated lithium iron phosphate composite anode material and preparation method thereof

A carbon-coated lithium iron phosphate and composite cathode material technology, which is applied to battery electrodes, electrical components, circuits, etc., can solve problems such as failure to exhibit rate and cycle performance, incomplete carbon coating, and lack of conductive network connections. Achieve the effect of improving the overall electronic conductivity, low cost, and high cycle performance

Active Publication Date: 2015-12-30
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the traditional lithium iron phosphate production process, most of them adopt ion doping and simple carbon coating technology, and the obtained LiFePO 4 Due to the incomplete coating of carbon, and the coated LiFePO 4 Lack of conductive network connection between particles, thus can not show good rate and cycle performance

Method used

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  • C3N4-carbon-coated lithium iron phosphate composite anode material and preparation method thereof
  • C3N4-carbon-coated lithium iron phosphate composite anode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Example 1: C 3 N 4 Preparation of nanosheets

[0025] Weigh 20 grams of melamine or dicyandiamide or urea into a crucible, place it in a muffle furnace, heat it to 550°C at a rate of 2°C per minute, and keep it at 550°C for 5 hours. It was taken out and ground to give a yellow powder C 3 N 4 sample. Weigh 1 g of yellow C 3 N 4 Put the sample into a jar, add 100 ml of isopropanol, place it in an ultrasonic machine for 10 hours to form a suspension, then centrifuge the suspension at 3000 rpm for 10 minutes to remove the sediment, and then remove the upper layer The suspension was centrifuged at a high speed of 12,000 rpm to obtain a light yellow solid C 3 N 4 The nanosheets are about 0.7 grams.

Embodiment 2

[0027] At room temperature, 0.35 g C 3 N 4 The nanosheets were dispersed in 100ml of deionized water and stirred evenly to prepare C 3 N 4 nanosheet suspension, and then 11.21 grams of FeCl 3 ·6H 2 O was added to this suspension. Then 5.48 g (NH 4 ) 2 HPO 4 The mixed solution of pyrrole monomer was slowly added to FeCl 3 / C 3 N 4 in the mixed solution. The mixed solution was stirred for 3 hours, filtered, washed with deionized water, and dried to obtain C 3 N 4 -Fe 3 PO 4 Precursor powder. Weigh 4.23 g of CH 3 COOLi·2H 2 O is dissolved in the mixed solution of ethanol and water, and C is added 3 N 4 -Fe 3 PO 4 Precursor powder and 0.5 gram of sucrose, after evaporating the solvent to dry, place in a tube furnace, and use 99% nitrogen as a protective gas, and raise the furnace temperature to 700 °C at a heating rate of 3 °C per minute, at 700 °C Insulated for 8 hours, then naturally cooled to room temperature to obtain a gray-black final product.

[0028]...

Embodiment 3

[0032] At room temperature, 0.6 g of C 3 N 4 Nanosheets were dispersed in 100ml of deionized water, stirred evenly, and then 11.21 grams of FeCl 3 ·6H 2 O join this C 3 N 4 nanosheet suspension. 5.48 g (NH 4 ) 2 HPO 4 The mixed solution of pyrrole monomer was slowly added to FeCl 3 / C 3 N 4 In the mixed solution, the mixed solution was stirred for 3 hours and then filtered, washed with deionized water, and dried to obtain C 3 N 4 -Fe 3 PO 4 Precursor powder. Weigh 4.23 g of CH 3 COOLi·2H 2 O is dissolved in the mixed solution of ethanol and water, and C is added 3 N 4 -Fe 3 PO 4 Precursor powder and 0.9 g of sucrose, after evaporating the solvent to dry, place in a tube furnace, and use 99% nitrogen as a protective gas, and raise the furnace temperature to 700 °C at a heating rate of 3 °C per minute. Insulated for 8 hours, then naturally cooled to room temperature to obtain a gray-black final product. Subsequent electrode preparation and half-cell prepara...

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Abstract

The invention discloses a C3N4-carbon-coated lithium iron phosphate composite anode material. The C3N4-carbon-coated lithium iron phosphate composite anode material consists of a layered material C3N4 and carbon-coated lithium iron phosphate, wherein the weight percent of the C3N4 is 0.5 to 10 percent, the weight percent of non-C3N4 carbon is 0.2 to 10, and the weight percent of lithium iron phosphate is 80 to 99.3 percent. The preparation method comprises the following steps: preparing C3N4 in a sintering manner, ultrasonically stripping, and carrying out the nanocrystallization; adding an iron source and a phosphorus source into a C3N4 suspension solution, and filtering and washing a mixture precipitate; uniformly mixing a precipitate product with a lithium source and a carbon source, and calcining the mixture under the protection of inert gas at a high temperature to obtain the C3N4-carbon-coated lithium iron phosphate composite anode material. The anode material prepared in the method is small in primary particle size, high in ion electric conductivity and electron electric conductivity, high in discharge capacity and excellent in rate capability and cycling performance.

Description

technical field [0001] The invention belongs to the field of positive electrode materials for lithium ion secondary batteries, and in particular relates to a C 3 N 4 Composite carbon-coated lithium iron phosphate cathode material and a preparation method thereof. Background technique [0002] Lithium-ion battery technology has made great progress since Japan's Sony Corporation successfully produced commercial lithium-ion batteries in 1991. Lithium-ion batteries have long cycle life and good safety performance, making them have broad application prospects in portable electronic devices, electric vehicles, energy storage power stations, space technology, defense industry, etc., and have become a research hotspot that has attracted widespread attention in recent years. And it has a very broad application prospect. [0003] Lithium iron phosphate has an olivine structure. Due to its good electrochemical performance, the charging and discharging platform is very stable, the st...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62
CPCH01M4/366H01M4/5825H01M4/625Y02E60/10
Inventor 高二平
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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