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Method for preparing ferrous silicate lithium of anode material of lithium ion battery

A lithium ferrous silicate and lithium ion battery technology, which is applied in battery electrodes, silicates, alkali metal silicates, etc., can solve the problem of poor electrochemical performance of synthetic materials, limiting the process of lithium ferrous silicate, and controlling conditions Harsh and other problems, to achieve the effect of reducing material cost, good discharge performance, and short synthesis cycle

Inactive Publication Date: 2013-01-16
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these methods have some inherent disadvantages, such as: high synthesis temperature, long synthesis period, harsh control conditions, high cost, and poor electrochemical properties of the synthesized materials. These factors have greatly limited the lithium ferrous silicate industry. the process of

Method used

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  • Method for preparing ferrous silicate lithium of anode material of lithium ion battery
  • Method for preparing ferrous silicate lithium of anode material of lithium ion battery
  • Method for preparing ferrous silicate lithium of anode material of lithium ion battery

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Experimental program
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Effect test

Embodiment 1

[0020] Mix the raw materials 0.2mol tetraethyl orthosilicate, 0.2mol lithium carbonate, and 0.1mol iron oxide; add 0.2mol reducing agent malic acid, mix well, and activate mechanically for 0.5 hours according to the existing technology; then put it into a tube furnace, Under an argon atmosphere, the temperature was kept constant at 550°C, 650°C, 750°C, and 850°C for 16 hours, respectively. The resulting material is analyzed by X-ray diffraction to be the Pmn21 space group, which is Li 2 FeSiO 4 Structure. The particle size obtained by SEM is about 200nm. The obtained products were assembled into button batteries to measure their charge-discharge specific capacity and cycle performance. Charge and discharge were carried out at a rate of 0.1C. Their initial discharge capacity and discharge capacity after 30 cycles are shown in Table 1.

[0021]

Embodiment 2

[0023] Use 0.1mol iron nitrate, 0.2mol lithium formate, 0.1mol methyl silicate as raw materials; add reducing agent 0.6mol mandelic acid, mix well, and mechanically activate for 10 hours; then put it into a tube furnace, under hydrogen atmosphere , and the temperature was kept constant at 700° C. for 8 hours. The resulting material is analyzed by X-ray diffraction to be the Pmn21 space group, which is Li 2 FeSiO 4 Structure. The particle size of the product obtained by SEM is about 200nm. The obtained product was assembled into a button battery to measure its charge-discharge specific capacity and cycle performance, and the charge-discharge was carried out at a rate of 0.1C, and the discharge specific capacity was as high as 155 mAh·g -1 , the discharge capacity after 50 cycles is 152 mAh·g -1 .

Embodiment 3

[0025] Use 0.1mol iron carbonate, 0.2mol lithium oxide, 0.2mol silicon tetrachloride as raw materials; add reducing agent 4mol oxalic acid, 0.2mol isopropanol, mix well, and mechanically activate for 8 hours; then put it into a tube furnace , under a nitrogen atmosphere, the temperature was kept constant at 660° C. for 48 hours. The obtained material is analyzed by X-ray diffraction in the Pmn21 space group, which is Li 2 FeSiO 4 Structure. The obtained product was assembled into a button battery to measure its charge-discharge specific capacity and cycle performance, and the charge-discharge was carried out at a rate of 0.1C, and the initial discharge capacity was 152 mAh·g -1 , the discharge capacity after 50 cycles is 149 mAh·g -1 .

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Abstract

A method for preparing ferrous silicate lithium of anode material of a lithium ion battery comprises the following steps: mixing iron-source compound, silicon-source compound and lithium-source compound according to the mole ratio of iron, silicon and lithium being 1:1:2, mixing the mixture uniformly under room temperature, and adding reducing agent into the mixture according to the mole ratio ofthe reducing agent and the iron-source compound being 1:1-20:1; mechanically activating the mixture for 0.5-48h according to the prior art; under the condition of normal temperature and normal pressure, reducing ferric iron by the reducing agent and preparing amorphous Li2FeSiO4 with a smaller size, then heating the Li2FeSiO4 to the temperature of 550-850 DEG C under the non-oxidability atmosphere, forging the Li2FeSiO4 for 3-48h at a constant temperature, thus obtaining ferrous silicate lithium. Under the normal temperature and normal pressure, the reducing agent is utilized for directly reducing the ferric iron and synthesizing amorphous Li2FeSiO4, the synthesizing temperature is low, the synthesizing period is short, the synthesizing method is simple, the production cost is lowered greatly, and the industrialization is easy to realize. The prepared Li2FeSiO4 product has higher specific capacity and better rate discharging performance.

Description

technical field [0001] The invention relates to a preparation method of lithium ferrous silicate, a lithium ion cathode material. Background technique [0002] Li 2 FeSiO 4 It is a new type of cathode material for lithium-ion batteries. It has the advantages of high theoretical specific capacity, stable structure, excellent cycle performance, low price, and environmental friendliness. It is considered to be a very competitive cathode material for lithium-ion batteries in the future, and is expected to be widely used in lithium-ion power batteries. The traditional preparation methods mainly include the following: high-temperature solid-phase sintering method, sol-gel method, hydrothermal method, etc. However, these methods have some inherent disadvantages, such as: high synthesis temperature, long synthesis period, harsh control conditions, high cost, and poor electrochemical properties of the synthesized materials. These factors have greatly limited the lithium ferrous si...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/1397C01B33/32
CPCY02E60/10
Inventor 郑俊超张宝张佳峰
Owner CENT SOUTH UNIV