Sodium fluoride impregnated and coated vanadium-doped porous structure sodium ferric pyrophosphate positive electrode material and preparation method thereof

A technology of sodium iron pyrophosphate and positive electrode materials, which is applied in the field of lithium-ion battery technology and electrochemistry, can solve the problems of low specific capacity, achieve the effects of improving electrical conductivity, avoiding structural collapse, and excellent cycle performance

Inactive Publication Date: 2021-06-04
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The preparation method of sodium ferric pyrophosphate material is simple and the cycle performance is good, but its specific capacity is lower than other sodium ion cathode materials

Method used

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  • Sodium fluoride impregnated and coated vanadium-doped porous structure sodium ferric pyrophosphate positive electrode material and preparation method thereof
  • Sodium fluoride impregnated and coated vanadium-doped porous structure sodium ferric pyrophosphate positive electrode material and preparation method thereof
  • Sodium fluoride impregnated and coated vanadium-doped porous structure sodium ferric pyrophosphate positive electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Embodiment 1, prepare Na 2 FeP 2 o 7 Material

[0032] First, take 0.9085g (5mmol) of ferrous oxalate dihydrate and 1.2121g (10mmol) of anhydrous sodium dihydrogen phosphate, put them into a polytetrachlorethylene ball mill jar, add acetone and ball mill for 6 hours, and then place them in a vacuum drying oven at 50°C After drying for 2 hours and grinding for 1 hour, the precursor powder was obtained.

[0033] The precursor powder is heated to 560°C at a heating rate of 2°C / min in a tube furnace with argon gas for 12 hours, and then cooled with the furnace. After the obtained product is ground, Na 2 FeP 2 o 7 Material.

[0034] Adjust the sintering temperature in the above preparation method to 600°C and 640°C respectively, and prepare Na 2 FeP 2 o 7 Material. figure 1 Na obtained under the condition of 600℃ 2 FeP 2 o 7 The SEM image of the material, it can be seen from the image that the sodium iron pyrophosphate positive electrode material shows agglomera...

Embodiment 2

[0037] Embodiment 2, prepare Na 2 Fe 1-1.5x V x P 2 o 7 Material

[0038] First take 0.7722g (4.25mmol) of ferrous oxalate dihydrate, 1.2121g (10mmol) of anhydrous sodium dihydrogen phosphate and 0.0591g (0.5mmol) of ammonium metavanadate, put them into a polytetrachlorethylene ball mill jar, add acetone After ball milling for 6 hours, drying in a vacuum oven at 50°C for 2 hours, and grinding for 1 hour to obtain the precursor powder.

[0039] The precursor powder was heated to 600°C at a heating rate of 2°C / min in a tube furnace with argon gas for 12 hours, and then cooled with the furnace. The obtained product was ground to obtain Na 2 Fe 0.85 V 0.1 P 2 o 7 Material.

[0040] The amount of raw materials in the above preparation method is adjusted to 0.7041g (3.875mmol) ferrous oxalate dihydrate, 1.2121g (10mmol) anhydrous sodium dihydrogen phosphate, 0.0886g (0.75mmol) ammonium metavanadate, according to the same method as above Preparation of vanadium-doped sodiu...

Embodiment 3

[0044] Embodiment 3, preparation NaF@Na 2 Fe 0.775 V 0.15 P 2 o 7

[0045] First take 0.7041g (3.875mmol) of ferrous oxalate dihydrate, 1.2121g (10mmol) of anhydrous sodium dihydrogen phosphate and 0.0886g (0.75mmol) of ammonium metavanadate, put them into a polytetrachloroethylene ball mill tank, add acetone After ball milling for 6 hours, drying in a vacuum oven at 50°C for 2 hours, and grinding for 1 hour to obtain the precursor powder.

[0046] The precursor powder was heated to 600°C at a heating rate of 2°C / min in a tube furnace with argon gas for 12 hours, and then cooled with the furnace. The obtained product was ground to obtain Na 2 Fe 0.775 V 0.15 P 2 o 7 Material.

[0047] Na 2 Fe 0.775 V 0.15 P 2 o 7 The material and 0.0294g (0.49mmol) sodium chloride were added to deionized water, stirred evenly by ultrasonic, and then 49mL 0.01mol / L potassium fluoride aqueous solution was added dropwise through a peristaltic pump to obtain a suspension; the suspen...

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Abstract

The invention discloses a sodium fluoride impregnated and coated vanadium-doped porous structure sodium ferric pyrophosphate positive electrode material and a preparation method thereof, the positive electrode material is obtained by impregnating and coating sodium fluoride on the surface of sodium ferric pyrophosphate doped with vanadium in situ, and the structural general formula is NaF (at) Na2Fe1-1.5 xVxP2O7. The Na2FeP2O7 material is coated with a proper amount of sodium fluoride and doped with a proper amount of vanadium, so that the crystal structure of the ferric sodium pyrophosphate with a triclinic crystal structure can keep high stability in the process of embedding and de-embedding sodium ions, and the material has excellent cycle performance and good coulombic efficiency; sharp reduction of circulation caused by structure collapse after sodion deintercalation is effectively avoided,the stability of the material is improved, the conductivity is improved to a certain extent, thereby being beneficial to improving the electrochemical performance of the material.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery technology and electrochemistry, and in particular relates to a sodium fluoride-impregnated and coated vanadium-doped porous structure sodium iron pyrophosphate positive electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries are a new type of chemical power source that are considered most attractive for electric vehicles (EVs) and hybrid electric vehicles (HEVs) due to their high energy, high power density, long cycle life, low self-discharge, and high cost performance. strong candidate materials. However, due to the low content of lithium in the earth's crust, large-scale energy storage cannot be performed, so sodium-ion batteries have become one of the promising materials. [0003] Compared with lithium-ion batteries, although sodium-ion batteries have advantages and opportunities, the two are also very different: the radius of sodium ions is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M10/054
CPCH01M4/364H01M4/366H01M4/582H01M4/5825H01M10/054H01M2004/021H01M2004/028Y02E60/10
Inventor 张大伟宋莹
Owner HEFEI UNIV OF TECH
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