Preparation method for ferrous silicate lithium cathode material simultaneously doped with fluorine and zirconium

A technology for lithium ferrous silicate and positive electrode materials, which is applied in the direction of silicate, alkali metal silicate, battery electrodes, etc., can solve the problems of poor discharge performance, achieve low raw material cost, good cycle performance, and wide source of raw materials Effect

Inactive Publication Date: 2011-04-13
FUJIAN NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] As a result of the Li prepared by the above method 2 FeSiO 4 The discharge performance at a lower rate is still poor. In recent years, many researchers have tried to use doping methods to further improve the electrochemical performance of lithium ferrous silicate.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The reactants weigh lithium carbonate, ferrous oxalate, zirconium dioxide, tetraethyl silicate, Lithium fluoride, weigh polypropylene according to 1% of the total mass of reactants.

[0022] Mix tetraethyl silicate with hot water at a temperature of 50° C., add lithium carbonate, stir and mix, and then mix in all other reactants and polypropylene. The amount of hot water used is 0.10 times the total volume of the solids of all reactants. Mix by ball milling at a speed of 100rpm for 10 minutes; dry in a vacuum at a temperature of 50°C and a pressure of 10Pa to prepare a dry powder, place the dry powder in a nitrogen atmosphere, and heat it from room temperature to 200°C, keep this temperature for sintering for 3 hours, then further heat to 550°C at a heating rate of 0.5°C / min, keep this temperature for sintering for 3 hours, and prepare lithium ferrous silicate.

Embodiment 2

[0024] The reactant is weighed lithium hydroxide, ferrous acetate, zirconium hydroxide, tetramethyl silicate according to the molar ratio of lithium ion: ferrous ion: zirconium ion: silicon ion: fluorine ion is 2.05: 0.90: 0.10: 0.90: 0.10 , Sodium fluoride, weigh polyacrylamide according to 30% of the total mass of reactants.

[0025]Mix tetramethyl silicate with hot water at a temperature of 98°C, add lithium hydroxide, stir and mix, and then mix in all other reactants and polyacrylamide. The amount of hot water used is the total solid volume of all reactants 10 times the volume, mixed with a ball mill at a speed of 900 rpm for 5 hours, and dried in a vacuum at a temperature of 150° C. and a pressure of 10132 Pa to prepare a dry powder. Place the dried powder in an argon atmosphere, heat it from room temperature to 500°C at a heating rate of 30°C / min, keep this temperature for sintering for 12 hours, and then further heat it to 850°C at a heating rate of 30°C / min. Keep this...

Embodiment 3

[0027] The reactants are lithium oxalate, ferrous hydroxide, potassium fluozirconate, nanometer dioxide Silicon, ammonium fluoride, weigh flour based on 15% of the total mass of reactants.

[0028] Mix nano-silica with hot water at a temperature of 80°C, add lithium oxalate, stir and mix, and then mix in all other reactants and flour. The amount of hot water is 5 times the volume of the total solid volume of all reactants. Mixed by ball milling at a speed of 600 rpm for 3 hours, and dried in a vacuum at a temperature of 100° C. and a pressure of 1010 Pa to prepare a dry powder. Place the dry powder in a carbon monoxide atmosphere, heat from room temperature to 400°C at a heating rate of 10°C / min, keep this temperature for sintering for 8 hours, and then further heat to 750°C at a heating rate of 15°C / min, keep This temperature was sintered for 24 hours to prepare lithium ferrous silicate.

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PUM

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Abstract

The invention relates to a preparation method for a ferrous silicate lithium cathode material simultaneously doped with fluorine and zirconium, which is characterized by comprising the following steps of: weighing a lithium compound, a ferrous compound, a zirconium compound, a silicon compound and a fluorine compound as reactants in accordance with the molar ratio of lithium ion to ferrous ion to zirconium ion to silicon ion to fluorine ion being (1.90-2.05): (1-y): x: (1-z): k; weighing a carbon-containing compound or carbon powder based on 1-30 percent of total mass of the reactants; mixing the silicon compound with hot water, adding the lithium compound, then mixing all other reactants and the carbon-containing compound or the carbon powder, carrying out ball mill mixture process and vacuum drying to prepare dry powder; and placing the dry powder in an inert atmosphere or a weakly reducing atmosphere, and then preparing ferrous silicate lithium through the two-stage sintering process. The cycle performance of the prepared material is excellent in the 1C-rate current, and a good foundation can be built for industrialization.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery electrode materials, and relates to a preparation method of a lithium ferrous silicate cathode material that is doped with fluorine and zirconium at the same time and can be used for lithium-ion batteries, lithium batteries and supercapacitors. technical background [0002] Lithium-ion batteries are widely used in mobile communications, notebook computers, portable electric tools, and are also the preferred power source for electric vehicles. The main factor affecting the performance and price ratio of lithium-ion batteries is the performance of its cathode materials. Since 2000, Armand et al [Patent US 6085015] have applied for a patent for the preparation of lithium ferrous silicate, Nytén et al [Nyten A, et al., Electrochem.Commun., 2005, 7 (2): 156-160.] The orthorhombic structure of lithium ferrous silicate has been reported, and the research on lithium ferrous silicate has attra...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1397C01B33/32
CPCY02E60/122Y02E60/12Y02E60/10
Inventor 童庆松张贵萍陈梅蓉吴永文郑华杰常美娟
Owner FUJIAN NORMAL UNIV
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