Preparation method of rare earth compound doped lithium ferrous silicate cathode material

A technology of lithium ferrous silicate and rare earth compounds, 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, simple preparation process, and good discharge performance Effect

Inactive Publication Date: 2011-03-02
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 under low current is still poor. In recent years, attempts have been made to further improve the electrochemical performance of lithium ferrous silicate by doping.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The reactants are weighed lithium carbonate, ferrous oxalate, dilanthanum trioxide, tetraethyl silicate according to the molar ratio of lithium ion: ferrous ion: lanthanum ion: silicon ion is 1.90: 0.998: 0.04: 1, according to the mass of reactant 1% of the total weighted polypropylene.

[0021] Add tetraethyl silicate into hot water at a temperature of 50°C with an amount equal to 1 times the total solid volume of the reactants, add lithium carbonate, stir and mix, mix in all other reactants and polypropylene, and mix with a ball mill at a speed of 100rpm 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, heat from room temperature to 200°C at a heating rate of 0.5°C / min, and keep this temperature for sintering 3 hours, and then further heated to 550° C. at a heating rate of 0.5° C. / min, and kept at this temperature for sintering for 3 hours to prepare lithium ferrous silicat...

Embodiment 2

[0023] The reactant is weighed lithium hydroxide, ferrous chloride, praseodymium dioxide, trimethyl silicate according to the molar ratio of lithium ion: ferrous ion: praseodymium ion: silicon ion is 1.90: 0.90: 0.0125: 1, according to reactant 30% of the sum of mass weighs glucose.

[0024] Add trimethyl silicate into hot water at a temperature of 90°C. The amount of hot water is 20 times the total volume of the reactant solids, then add lithium hydroxide, stir and mix, mix in all other reactants and glucose, and use a speed of 900rpm Ball milling and mixing for 5 hours; drying in a vacuum at a temperature of 150°C and a pressure of 10132Pa to prepare a dry powder; place the dry powder in a carbon monoxide atmosphere, and heat it from room temperature to 500°C at a heating rate of 30°C / min. The temperature was sintered for 12 hours, and then further heated to 550°C at a heating rate of 30°C / min, and kept at this temperature for sintering for 24 hours to prepare lithium ferrou...

Embodiment 3

[0026] The reactants are weighed lithium chloride, ferrous sulfate, scandium nitrate, nano-silicon dioxide according to the molar ratio of lithium ion: ferrous ion: scandium ion: silicon ion: 2.05: 0.90: 0.067: 1 15% weighed sucrose.

[0027] Add nano-silica to ethanol aqueous solution at a temperature of 80°C. The ethanol aqueous solution is a mixed solution with a volume ratio of ethanol and water of 1:1. Lithium chloride is added, stirred and mixed, and all other reactants and sucrose are mixed in. The amount of the mixed solution of ethanol and water is 10 times the volume of the total solid volume of the reactant; it is mixed with a ball mill at a speed of 500rpm for 1 hour; it is dried in a vacuum at a temperature of 100°C and a pressure of 1010Pa to prepare a dry powder; the dry powder is placed in In a carbon dioxide atmosphere, heat from room temperature to 400°C at a heating rate of 20°C / min, keep this temperature for sintering for 10 hours, then further heat at a he...

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Abstract

The invention relates to a preparation method of rare earth compound doped lithium ferrous silicate cathode material. The preparation process includes the following steps: reactants of lithium compound, ferrous compound, rare earth element compound and silicon compound are weighed according to the mol ratio that lithium ion: ferrous ion: rare earth element ion: silicon ion is equal to (1.90-2.05): (1-y): z: 1, and a certain amount of carbon containing compound is added. Silicon compound and hot water or ethanol water are mixed, lithium compound is added, stirring and mixing are carried out, the other reactants and carbon containing compound are added, and vacuum drying is carried out. The dried powder is used for preparing lithium ferrous silicate by adopting two-stage sintering method. Discharging capacity of the prepared material at 3.0V region is obviously improved, and cycle performance at 0.3C current is good, thus laying good foundation 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 doped with a rare earth compound, which 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 the cathode material. 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 attracted attention. Lithium...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/32H01M4/58
CPCY02E60/10
Inventor 童庆松陈梅蓉伍仁强李秀华施继成黄行康郑华杰
Owner FUJIAN NORMAL UNIV
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