Method for preparing doped ferrous-lithium metasilicate anode material from micro silicon powder

A technology of lithium ferrosilicate and cathode material, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of slow lithium ion diffusion and low electronic conductivity, and achieve good cycle performance, high charge-discharge capacity, wide The effect of the application foreground

Inactive Publication Date: 2012-06-20
LANZHOU UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Li 2 FeSiO 4 The main disadvantage is its extremely low electronic conductivity (6×10 -14 S cm), the diffusion of lithium ions is slow, and it is necessary to p

Method used

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  • Method for preparing doped ferrous-lithium metasilicate anode material from micro silicon powder
  • Method for preparing doped ferrous-lithium metasilicate anode material from micro silicon powder
  • Method for preparing doped ferrous-lithium metasilicate anode material from micro silicon powder

Examples

Experimental program
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Effect test

Embodiment 1

[0026]Weigh 4.72g of silica fume, put it into a 100ml beaker filled with 50m / 4mol / L hydrochloric acid solution, heat to boiling, and remove the contained Fe 2 o 3 、Al 2 o 3 , MgO, CaO and NaO, the main content is Fe 2 o 3 , filtered and washed until the filtrate was colorless, then dried to obtain 3.59g of treated silica fume, Fe 2 o 3 The weight of etc. is 1.13g, and content is 24%. Weigh 1.00 g of the micro-silicon powder, and measure the carbon content of the micro-silicon powder as 5% by the 800° C. high temperature ignition weight loss method. Therefore, SiO in silica fume 2 The content is 71%.

[0027] Weigh ferrous oxalate (4.66g), microsilica (3.39g), lithium carbonate (2.96g) and sucrose (0.70g) into a ball mill jar, ball mill and mix in absolute ethanol, then vacuum dry at 60°C A precursor mixture is obtained. The precursor is pressed into tablets, pre-calcined at 400°C for 3 hours in nitrogen, and then roasted at 750°C for 8 hours. During the solid-state r...

Embodiment 2

[0030] According to the SiO of the microsilica powder of embodiment 1 2 content, designed to prepare ion-doped Li 2 FeSiO 4 / C composite cathode material. Weigh ferrous oxalate (4.66g), microsilica (3.39g), lithium carbonate (2.96g) and sucrose (3.91g) into a ball mill jar, ball mill and mix in absolute ethanol, then vacuum dry at 60°C A precursor mixture is obtained. The precursor is pressed into tablets, pre-calcined at 400°C for 3 hours in nitrogen, and then roasted at 750°C for 8 hours. During the solid-state reaction at high temperature, the ferric iron is reduced to ferrous iron by carbon (the carbon is sucrose pyrolysis Carbon or the carbon contained in microsilica powder), to obtain ion-doped Li 2 FeSiO 4 / C composite positive electrode material, the dopant ion is Al contained in micro-silicon powder 3+ , Mg 2+ , Ca 2+ and Na + Wait. Assemble the button battery according to the method described in Example 1, and under the charge and discharge voltage range of...

Embodiment 3

[0032] Weigh ferrous oxalate (4.66g), microsilica (3.41g), lithium carbonate (2.96g) and sucrose (7.10g) into a ball mill jar, ball mill and mix in absolute ethanol, then vacuum dry at 60°C A precursor mixture is obtained. The precursor is pressed into tablets, pre-calcined at 400°C for 3 hours in nitrogen, and then roasted at 750°C for 8 hours. During the solid-state reaction at high temperature, the ferric iron is reduced to ferrous iron by carbon (the carbon is sucrose pyrolysis carbon or the carbon contained in microsilica powder), to obtain Li 2 FeSiO 4 / C composite cathode material. Assemble the button battery according to the method described in Example 1, and under the charge and discharge voltage range of 1.5 ~ 4.8V, the discharge specific capacity measured when it is charged and discharged at 0.1C, 0.5C and 1C is 134.30mAh / g, 122.30mAh / g, 103.80mAh / g. The SEM images of the prepared samples are shown in figure 1 , see the cycle curve at 1C figure 2 , see the c...

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Abstract

The invention relates to a method for preparing a doped ferrous-lithium metasilicate anode material from micro silicon powder. According to the method, the micro silicon powder, a carbon source, a lithium source and an iron source are subjected to a solid phase reaction in an inert atmosphere to prepare a metal ion doped Li2FeSiO4/C cathode material, wherein in the process of the solid phase reaction, the trivalent Fe in the micro silicon powder is deoxidized into bivalent Fe. The micro silicon powder used in the method disclosed by the invention is a rejected material generated during production of a ferrous-silicon enterprise and is a low-price silicon source, the particle size of the micro silicon powder is 50 to 500 nm, and the micro silicon powder is doped with a variety of metal ions and a certain amount of carbon, so that the micro silicon powder is an ideal silicon source for preparing the doped Li2FeSiO4 cathode material with a low price and fine quality, and has a wide application prospect.

Description

technical field [0001] The invention relates to a preparation method of a positive electrode material of a lithium ion battery. technical background [0002] Silicate-based cathode material Li 2 FeSiO 4 It is a new type of positive electrode material that has appeared in recent years. It has the same properties as LiFePO 4 Similar molecular formula, stable structure, good overcharge resistance; in addition, Si is more abundant than P resources, Li 2 FeSiO 4 Cathode materials will be cheaper. With the development of technology, rust and sand may be used to prepare high-performance Li batteries in the future. 2 FeSiO 4 Cathode material. Therefore, Li 2 FeSiO 4 The cathode material is an ideal cathode material for power batteries. Once the cheap high-performance Li 2 FeSiO 4 With the successful development of cathode materials, electric vehicles may enter our daily life and become our effective means of transportation. However, currently the Li 2 FeSiO 4 Most of th...

Claims

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Application Information

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IPC IPC(8): H01M4/1397H01M4/58
CPCY02E60/122Y02E60/10
Inventor 张庆堂冯辉霞赵永乐李明洋刘小育
Owner LANZHOU UNIVERSITY OF TECHNOLOGY
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