Solid phase-hydrothermal preparation method for lithium vanadium phosphate

A lithium vanadium phosphate and hydrothermal technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of low product yield, uneven distribution, cumbersome operation process, etc., and achieve high rate performance, excellent reaction The effect of mild conditions and simple operation process

Inactive Publication Date: 2012-11-14
SICHUAN UNIV
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

The solid-phase method is simple to operate, but the prepared material has large particles, uneven distribution, poor cycle stability and rate performance; the sol-gel method has a complicated process, large drying shrinkage, and the obtained material has irregular morphology and is easy to agglomerate ; At present, the hydrothermal method prepares lithium vanadium phosphate, and adopts V containing +5 valence V 2 o 5 and NH 4 VO 3 As a vanadium source, a strong reducing agent such as ascorbic acid needs to be added, and it is not easy to convert V 5+ fully restored to V 3+ , the product yield is low, the purity is not high, and the particle distribution is uneven. After the hydrothermal reaction is completed, the obtained precipitate needs to be treated with solid-phase carbon coating. The operation process is cumbersome and the carbon coating effect is not good.

Method used

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  • Solid phase-hydrothermal preparation method for lithium vanadium phosphate
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  • Solid phase-hydrothermal preparation method for lithium vanadium phosphate

Examples

Experimental program
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Effect test

Embodiment 1

[0042] In this example, Li 3 V 2 (PO 4 ) 3 The processing steps of the / C preparation method are as follows:

[0043] (1) Preparation of VPO 4 / C intermediate

[0044] The raw materials and their supplies are: 0.1 mol of vanadium (11.697 g of ammonium metavanadate), 0.1 mol of phosphate (11.503 g of ammonium dihydrogen phosphate), 0.1 mol of carbon (2.8524 g of sucrose);

[0045] Put the supply of the above-mentioned raw materials into the ball mill tank, and add 5mL of distilled water to ball mill to disperse for 0.5h. Heating under protection to 650°C for 10 hours, after the holding time is over, naturally cool to room temperature with the furnace to obtain VPO 4 / C intermediate;

[0046] (2) Hydrothermal preparation of lithium vanadium phosphate

[0047] The raw materials and their supplies are: Lithium 0.09mol (LiOH·H 2 O 3.7764g), phosphate radical 0.03mol (mass fraction 85% phosphoric acid 3.4588g), VPO 4 / C intermediate 0.06mol (8.9305g, carbon content 1.95%);...

Embodiment 2

[0054] In this example, lithium vanadium phosphate Li 3 V 2 (PO 4 ) 3 The processing steps of the / C preparation method are as follows:

[0055] (1) Preparation of VPO 4 / C intermediate

[0056] The raw materials and their supplies are: 0.1mol of vanadium (9.904g of vanadium pentoxide), 0.1mol of phosphate (13.206g of diammonium hydrogen phosphate), and 0.5mol of carbon (17.5117g of citric acid);

[0057] Put the supply of the above raw materials into the ball mill tank, and add 20mL of acetone to ball mill to disperse for 3h. Heating under protection to 900°C for 4 hours, after the holding time is over, naturally cool to room temperature with the furnace to obtain VPO 4 / C intermediate;

[0058] (2) Hydrothermal preparation of lithium vanadium phosphate

[0059] The raw materials and their supplies are: Lithium 0.09mol (LiOH·H 2 O 3.7764g), phosphate radical 0.03mol (ammonium dihydrogen phosphate 3.4509g), VPO 4 / C intermediate 0.06mol (9.4171g, carbon content 7.55%...

Embodiment 3

[0066] In this example, lithium vanadium phosphate Li 3 V 2 (PO 4 ) 3 The processing steps of the / C preparation method are as follows:

[0067] (1) Preparation of VPO 4 / C intermediate

[0068] The raw materials and their supplies are: 0.1mol of vanadium (11.697g of ammonium metavanadate), 0.1mol of phosphate (13.206g of diammonium hydrogen phosphate), and 0.2mol of carbon (3.16g of stearic acid);

[0069] Put the supply of the above-mentioned raw materials into the ball mill tank, and add 40mL of absolute ethanol to ball mill to disperse for 6h. Heated to 800°C for 6 hours under the protection of nitrogen, and after the holding time was over, naturally cooled to room temperature with the furnace to obtain VPO 4 / C intermediate;

[0070] (2) Hydrothermal preparation of lithium vanadium phosphate

[0071] The raw materials and their supplies are: lithium 0.09mol (lithium acetate 9.1818g), phosphate radical 0.03mol (mass fraction 85% phosphoric acid 3.4588g), VPO 4 / C ...

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Abstract

The invention provides a solid phase-hydrothermal preparation method for lithium vanadium phosphate. The method comprises the following process steps that (1) providing materials of vanadium, phosphate radicals and carbon are metered according to a mol ratio of vanadium: phosphate radicals: carbon being 1:1:(1-10), dispersing agents are added for ball milling, obtained paste is dried and is then crushed, the materials are heated to 650 to 900 DEG C for heat insulation for 4 to 10 hours under the inert gas protection, the materials are naturally cooled to the room temperature along with a furnace to obtain VPO4 / C intermediates; (2) providing materials of lithium and phosphate radicals and the intermediates are metered according to a mol ratio of lithium: phosphate radicals: intermediates being 3:1:2, the providing materials of lithium and phosphate radicals are respectively prepared into water solution, water solution of the providing materials of the phosphate radicals is added into the water solution of the providing materials of lithium to form mixing solution, the intermediates are added into the mixed solution, water is added for dilution, then, the materials are transferred to a sealed high-pressure reaction kettle, are heated to 200 to 280 DEG C for heat insulation for 2 to 20 hours and are filtered, and filter cake is subjected to vacuum drying to obtain black powder; and (3) the black powder is heated to 600 to 850 DEG C for heat insulation for 1 to 10 hours under the inert gas protection, and the lithium vanadium phosphate is obtained.

Description

technical field [0001] The invention belongs to the field of lithium vanadium phosphate preparation, in particular to a solid phase-hydrothermal preparation method of lithium vanadium phosphate. Background technique [0002] Due to its high theoretical capacity (197mAh g -1 ), high working voltage, excellent rate performance and other advantages have attracted more and more attention from the industry, and it is also one of the anode materials with great potential for lithium-ion power batteries. However, due to its low electrical conductivity and slow diffusion rate of lithium ions, its practical applications are hindered. At present, the following methods are mainly used to improve: (1) surface coating carbon or other conductive substances to increase its electrical conductivity; (2) doping metal elements to increase its intrinsic electrical conductivity; (3) reducing the particle size of the material To shorten the diffusion path of lithium ions so as to reduce the prop...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45
Inventor 郭孝东钟本和唐艳刘恒王雁英
Owner SICHUAN UNIV
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