Method for preparation of Li2FeSiO4 and Li2FeSiO4/C anode material

A lithium iron silicate and carbon positive electrode technology, which is applied in battery electrodes, electrical components, electrochemical generators, etc., can solve problems such as hindering industrial production, product agglomeration, and local heating too fast, so as to reduce synthesis conditions and raw materials The effect of cost, high cycle specific capacity, and good cycle stability

Inactive Publication Date: 2014-11-05
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Microwave heating is difficult to control, and it may cause local heating too fast, resulting in rapid crystal growth and product agglomeration, which greatly limits the electrochemical performance of the material
[0009] In addition, because the iron source for the synthesis of lithium iron silicate generally uses divalent iron salts, which increases the production cost, and the divalent iron salts are easily oxidized during the preparation of the precursor, which is not conducive to the synthesis of pure phases. The disadvantages have greatly hindered Li 2 FeSiO 4 industrial production

Method used

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  • Method for preparation of Li2FeSiO4 and Li2FeSiO4/C anode material
  • Method for preparation of Li2FeSiO4 and Li2FeSiO4/C anode material
  • Method for preparation of Li2FeSiO4 and Li2FeSiO4/C anode material

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Experimental program
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Effect test

Embodiment 1

[0031] (1) Add tetraethyl orthosilicate and ferric nitrate in a molar ratio of 1:1 to a mixed solution of a certain proportion of absolute ethanol and deionized water to form solution A, and the concentration of orthosilicate is 0.16 molL -1 ; Add polyethylene glycol 200 and ammonia water to a mixed solution of a certain proportion of absolute ethanol and deionized water to form solution B, and the concentration of polyethylene glycol 200 is 0.08 molL -1 , the pH value of solution B is 10;

[0032] (2) During the rapid stirring of solution B, pour into solution A to form a precipitate;

[0033] (3) Add lithium acetate with a relative stoichiometric ratio to the mixed solution obtained in step (2), mix well and place it under 80 ° C water bath conditions to evaporate and dry, and finally obtain a reddish-brown precursor;

[0034](4) The precursor in step (3) was calcined at 700 °C for 10 h in a mixed gas of hydrogen and argon, and after cooling, lithium iron silicate / carbon (L...

Embodiment 2

[0037] (1) Add silicon tetrachloride and ferric nitrate to a mixed solution of a certain proportion of absolute ethanol and deionized water in a molar ratio of 1:1 to form a solution A with a silicon tetrachloride concentration of 0.16 molL -1 ; Add polyethylene glycol 200 and ammonia water to a mixed solution of a certain proportion of absolute ethanol and deionized water to form solution B, and the concentration of polyethylene glycol 200 is 0.08 molL -1 , the pH value of solution B is 10;

[0038] (2) During the rapid stirring of solution B, pour into solution A to form a precipitate;

[0039] (3) Add lithium acetate with a relative stoichiometric ratio to the mixed solution obtained in step (2), mix well and place it under 80 ° C water bath conditions to evaporate and dry, and finally obtain a reddish-brown precursor;

[0040] (4) The precursor in step (3) was calcined at 700 °C for 10 h in an argon atmosphere, and after cooling, lithium iron silicate / carbon (Li 2 FeSiO ...

Embodiment 3

[0043] (1) Add tetraethyl orthosilicate and iron oxalate in a molar ratio of 1:1 to a mixed solution of a certain proportion of absolute ethanol and deionized water to form solution A, and the concentration of orthosilicate is 1 molL -1 ; Add polyethylene glycol 200 and ammonia water to a mixed solution of a certain proportion of absolute ethanol and deionized water to form solution B, and the concentration of polyethylene glycol 200 is 0.2 molL -1 , the pH value of solution B is 10;

[0044] (2) During the rapid stirring of solution B, pour into solution A to form a precipitate;

[0045] (3) Add lithium acetate with a relative stoichiometric ratio to the mixed solution obtained in step (2), mix well and place it under 80 ° C water bath conditions to evaporate and dry, and finally obtain a reddish-brown precursor;

[0046] (4) The precursor in step (3) was calcined at 900 °C for 10 h in an argon atmosphere, and after cooling, lithium iron silicate / carbon (Li 2 FeSiO 4 / C) C...

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Abstract

Belonging to the technical field of new energy materials and electrochemistry, the invention discloses a method for preparation of a Li2FeSiO4 and Li2FeSiO4/C anode material. The method provided by the invention adopts an inorganic trivalent iron salt as the iron source and takes an organic dispersant as the carbon source. In the process of introducing the organic dispersant into co-precipitation, the dispersant is adsorbed on the surface of the obtained precipitate, thus effectively preventing agglomeration of precipitate particles. In a calcination process, the organic dispersant undergoes in situ decomposition to generate amorphous carbon coating the particles, thereby preventing further growth of the particles. At the same time, the amorphous carbon forms a conductive network on the material surface, thus increasing electronic conduction of the material and improving the electrochemical performance of the material. The method provided by the invention has the advantages of cheap raw materials and simple preparation process, and is easy for industrial production. By adjusting the dispersant content, the synthesized Li2FeSiO4 and Li2FeSiO4/C material has uniform particle size, good dispersibility, and excellent electrochemical performance, thus being a lithium ion battery anode material with broad application prospects.

Description

technical field [0001] The invention belongs to the technical field of new energy materials and electrochemical materials, and in particular relates to a method for preparing lithium iron silicate and lithium iron silicate / carbon cathode materials. [0002] Background technique [0003] As a new type of green chemical power source, lithium-ion batteries have the advantages of high charge and discharge voltage, high specific energy, long life, low consumption, no pollution, no memory effect, small self-discharge, small internal resistance, high cost performance, and less pollution. At present, it is the secondary battery with the widest application range and the most likely large-scale application in electric vehicles. As the cathode material in the key material of lithium-ion batteries, its performance not only directly affects the performance of the battery, but also has very important practical significance for reducing the cost of the battery and realizing the industrial...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/136H01M4/1397H01M4/133H01M4/1393
CPCH01M4/366H01M4/5825H01M4/625H01M10/0525Y02E60/10
Inventor 赵海雷杜雪飞卢瑶高春辉张天厚
Owner UNIV OF SCI & TECH BEIJING
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