Sol-gel method for preparing lithium ferrous phosphate anode material based on ferric phosphate

A technology for lithium ferrous phosphate and positive electrode materials, which is applied in electrode manufacturing, battery electrodes, electrical components, etc., can solve the problems that limit the large-scale industrialization of lithium ferrous phosphate, poor high-current discharge capacity of synthetic materials, and harsh control conditions. , to achieve the effect of excellent cycle performance, low price, uniform and stable performance

Inactive Publication Date: 2009-12-02
NANKAI UNIV
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Problems solved by technology

However, these methods have some inherent disadvantages, such as: high synthesis temperature, long synthesis cycle, harsh control conditions, high cost, and poor high-current discharge capacity of the synthesized materials.
These shortcomings have limited the large-scale industrialization of lithium iron phosphate

Method used

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  • Sol-gel method for preparing lithium ferrous phosphate anode material based on ferric phosphate
  • Sol-gel method for preparing lithium ferrous phosphate anode material based on ferric phosphate
  • Sol-gel method for preparing lithium ferrous phosphate anode material based on ferric phosphate

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preparation example Construction

[0019] In order to solve the technical problems, the present invention provides a sol-gel preparation method of lithium iron phosphate, a positive electrode material for lithium ion batteries based on iron phosphate. The specific implementation steps are: using iron phosphate and lithium source compounds as raw materials, Mix in proportion, add carbon source and organic complexing agent, dissolve in distilled water, heat and stir at 30-90°C for 0.5-5 hours until a sol is formed, dry the sol to obtain a xerogel, mix it evenly and put it into a tube In a type furnace, it is pre-calcined at a constant temperature of 300-450°C for 4-12 hours under the protection of an inert gas, and finally calcined at a constant temperature of 500-800°C for 4-24 hours under the protection of an inert gas.

[0020] The lithium source used in the present invention can be selected from one of lithium hydroxide, lithium oxide, lithium nitrate, lithium carbonate, lithium oxalate, lithium acetate, lithi...

Embodiment 1

[0029] Weigh 1.1213g iron phosphate, 0.7943g oxalic acid, 0.4344g lithium nitrate and 0.2248g sucrose, add distilled water to dissolve, stir at 65°C for 2 hours to form a gel, then put it into an oven to dry to obtain a xerogel; After grinding, it was pressed into tablets, put into a tube furnace and pre-fired at 300° C. for 6 hours under the protection of an inert gas to obtain a lithium iron phosphate precursor.

[0030] The precursor is ground and then pressed into tablets, put into a tube furnace and calcined at 600° C. for 8 hours under the protection of an inert gas to obtain a lithium iron phosphate cathode material.

[0031] figure 1 For the XRD pattern of the obtained material, a Rigaku D / Max III type X-ray diffractometer (Cu target ka ray, wavelength λ=0.15418 nm) was used. Compared with the standard card, it can be seen that the synthesized material is olivine (space group Pnma), and no diffraction peak of carbon is found in the spectrogram, indicating that the car...

Embodiment 2

[0035] Weigh 1.1213g iron phosphate, 0.2216g lithium carbonate, 1.3238g citric acid, add distilled water to dissolve, stir and evaporate at 90°C for 1 hour to form a gel, then put it in an oven to dry to obtain a xerogel; grind the xerogel Tablets were put into a tube furnace and pre-fired at 400° C. for 3 hours under the protection of an inert gas to obtain a lithium iron phosphate precursor.

[0036] The precursor was ground and then pressed into tablets, put into a tube furnace and calcined at 650° C. for 6 hours under the protection of an inert gas to obtain a lithium iron phosphate cathode material.

[0037] The resulting material is made into an electrode as follows:

[0038] Weigh the material obtained in Example 2, conductive carbon and polytetrafluoroethylene with a mass ratio of 85:10:5, mix them evenly and grind them, then make a circular pole piece with a diameter of 8mm, and dry it in a drying oven at 100°C 24 hours to obtain the positive electrode sheet, with pu...

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Abstract

The invention relates to a sol-gel method for preparing a lithium ferrous phosphate anode material based on ferric phosphate, which comprises the following steps: firstly, mixing the ferric phosphate with a lithium source compound according to a proportion; secondly, adding an organic complexant and a carbon source compound in the mixture, dissolving the mixture by adding water and stirring the mixture at a constant temperature to form a sol; thirdly, heating and drying the sol till a gel is formed; and after the gel is subjected to even mixing and full ball milling, presintering the gel in a tubular furnace at a certain temperature for a period of time under the protection of inert gas; and finally calcining the obtained product for certain time at a certain temperature under the protection of the inert gas to obtain the lithium ferrous phosphate anode material. The method uses the ferric phosphate as a raw material which has abundant source and is cheap and available, and greatly reduces the cost; and the sol-gel method allows reactants to realize the molecule-level mixing and greatly reduces the reaction temperature so as to reduce energy consumption and prepare the lithium ferrous phosphate anode material with excellent performance.

Description

【Technical field】 [0001] The invention relates to the field of lithium ion storage batteries, in particular to a sol-gel preparation method of iron phosphate-based lithium iron phosphate positive electrode material. 【Background technique】 [0002] Lithium-ion battery is a new type of green high-energy rechargeable battery that appeared in the early 1990s, and has become the focus of research and development all over the world. Common cathode materials for lithium-ion batteries include LiCoO 2 , LiNiO 2 , LiMn 2 o 4 etc., but LiCoO 2 Toxic, relatively low capacity, high raw material cost, and poor overcharge performance; LiNiO 2 It is difficult to prepare, the cost of raw materials is relatively high, and the preparation temperature is high, and the energy consumption is large; LiMn 2 o 4 The John-Teller effect is prone to occur during charge and discharge, and the structure is unstable. Therefore, the development of a cathode material with high capacity, low price, s...

Claims

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Application Information

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IPC IPC(8): H01M4/04H01M4/58
CPCY02E60/12Y02E60/10
Inventor 焦丽芳袁华堂王一菁彭文修高海燕孙均利
Owner NANKAI UNIV
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