Doping modified sodium vanadium fluorophosphates positive electrode material and preparation method thereof

The technology of sodium vanadium fluorophosphate and positive electrode material is applied in the field of doping and modified sodium vanadium fluorophosphate positive electrode material and its preparation, and can solve the problems of high synthesis temperature of sodium vanadium fluorophosphate, long sintering time at high temperature, material agglomeration and the like, Achieve the effect of improving charge-discharge specific capacitance and rate performance, low synthesis cost, and improving ionic conductivity

Inactive Publication Date: 2018-11-27
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Patent CN107819115A proposes calcium ion doping modification for sodium vanadium phosphate, in which calcium ion replaces vanadium site, expands the unit cell volume, increases the transport channel of sodium ion, and improves the rate performance of the material, but the introduction of calcium ion does not It will participate in the process of sodium intercalation and deintercalation reaction. The synthesis temperature of the doped modified sodium vanadium phosphate prepared by this method is relatively high, and the sintering time at high temperature is long, and the material prepared by blast drying at 80 ° C will produce more serious agglomeration phenomenon , so the process has disadvantages such as high energy consumption

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  • Doping modified sodium vanadium fluorophosphates positive electrode material and preparation method thereof
  • Doping modified sodium vanadium fluorophosphates positive electrode material and preparation method thereof

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Embodiment 1

[0031] 1) Sodium fluoride, potassium fluoride, ammonium metavanadate and ammonium dihydrogen phosphate are mixed and dissolved in the desulfurized adding oxalic acid with a molar ratio of 2:1 to vanadium in ammonium metavanadate in ionized water, and mixing at room temperature to prepare a uniformly mixed precursor solution;

[0032] 2) Transfer the precursor solution to a -40°C refrigerator for 12 hours, and then freeze-dry it for 24 hours to prepare the precursor powder; place it in a non-oxidizing atmosphere tube furnace for 2 hours at 300°C and 4 hours at 600°C to obtain Sodium vanadium fluorophosphate modified by potassium ion doping. The blank sample is sodium vanadium fluorophosphate without adding potassium fluoride, and other conditions remain unchanged.

[0033] The resulting product was packed into a button battery to measure its charge and discharge specific capacity, and its discharge specific capacity data is shown in Table 1.

[0034] Experimental condition an...

Embodiment 2

[0038] 1) Sodium fluoride, potassium fluoride, ammonium metavanadate and ammonium dihydrogen phosphate are mixed and dissolved according to the molar ratio of sodium, potassium, vanadium, phosphorus and fluorine elements in a molar ratio of 0.95:0.05:1:1:1 In deionized water, add oxalic acid with a molar ratio of 2:1 to ammonium metavanadate, and mix under normal temperature conditions to prepare a uniformly mixed precursor solution;

[0039] 2) Transfer the precursor solution to a -40°C refrigerator to freeze for 12h, then freeze-dry for 24h to prepare the precursor powder; place it in a non-oxidizing atmosphere tube furnace at 300°C for 2h, 500, 550, 600, 650 , 700°C for 4 hours to prepare potassium ion-doped sodium vanadium phosphate. The resulting product was assembled into a button cell to measure its charge and discharge specific capacity, and the discharge specific capacity data is shown in Table 2.

[0040] Experimental condition and result of table 2 embodiment 2

...

Embodiment 3

[0044] 1) Sodium fluoride, potassium fluoride, ammonium metavanadate and ammonium dihydrogen phosphate are mixed and dissolved according to the molar ratio of sodium, potassium, vanadium, phosphorus and fluorine in a ratio of 0.9:0.1:1:1:1 In deionized water, add oxalic acid with a molar ratio of 2:1 to ammonium metavanadate, and mix under normal temperature conditions to prepare a uniformly mixed precursor solution;

[0045]2) Transfer the precursor solution to a -40°C refrigerator for 12 hours, and then freeze-dry it for 24 hours to prepare the precursor powder; place it in a non-oxidizing atmosphere tube furnace for 2 hours at 300°C and 4 hours at 650°C to obtain Sodium Vanadium Phosphate Modified by Potassium Ion Doping 0.9 K 0.1 VPO 4 F. Pack the obtained product into a button battery to measure its charge and discharge specific capacity, and the discharge specific capacity at 0.1C, 0.5C, 1C, 5C, and 10C rates is 130mAh·g respectively -1 , 121mAh·g -1 , 117mAh·g -1 ...

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Abstract

The invention provides a doping modified sodium vanadium fluorophosphates positive electrode material and a preparation method thereof. The positive electrode material is represented by a general formula of Na(1-x)KxVPO4F, wherein x is more than or equal to 0 and less than or equal to 0.15. The preparation method disclosed by the invention comprises the following steps: mixing and dissolving various raw materials into deionized water to realize uniform mixing on a molecular level; freezing, and performing freeze-drying treatment to prepare a powdered material having the characteristics of excellent dispersion property, light particle aggregation and the like; and calcining twice at a medium temperature and a high temperature, thereby obtaining the doping modified sodium vanadium fluorophosphates positive electrode material with the advantages of being loose and porous, fine and uniformly distributed in particle system, high in purity and excellent in charge and discharge performance.

Description

technical field [0001] The invention relates to the technical field of sodium ion battery materials, in particular to a doped modified sodium vanadium vanadium phosphate cathode material and a preparation method thereof. Background technique [0002] With the utilization and development of new clean energy (solar energy, nuclear energy, tidal energy, wind energy, etc.), there is an urgent need for an energy storage material with low price, good safety and long life to store the converted electric energy. Among them, lithium-ion batteries have been widely used in electric vehicles, digital 3C products and other fields due to their high energy density, which has led to rising prices and is difficult to meet the requirements of large-scale energy storage. The sodium resources in sodium-ion batteries are widely distributed, abundant, and cheap, and belong to the same main group as lithium, which is an excellent candidate to replace lithium in secondary batteries; in addition, al...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/054H01M4/136
CPCH01M4/136H01M4/364H01M4/5825H01M4/626H01M10/054Y02E60/10
Inventor 王接喜盖晓臣颜果春李新海王志兴郭华军彭文杰胡启阳
Owner CENT SOUTH UNIV
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