Preparation method of lithium tetrafluoro (oxalato) phosphate and lithium difluoro (oxalato) phosphate

A technology of lithium difluorobis oxalate phosphate and lithium tetrafluorooxalate phosphate is applied in the field of lithium ion batteries, and can solve the problems of difficult control of chloride ion and acid value, high equipment requirements, hidden dangers and risks in safety and reliability, and the like, Achieve the effect of reducing equipment requirements, safe reaction conditions, and improving productivity

Inactive Publication Date: 2020-09-22
香河昆仑新能源材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method will also produce a large amount of HCl highly corrosive acid gas, which requires high equipment, and it is difficult...

Method used

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  • Preparation method of lithium tetrafluoro (oxalato) phosphate and lithium difluoro (oxalato) phosphate
  • Preparation method of lithium tetrafluoro (oxalato) phosphate and lithium difluoro (oxalato) phosphate
  • Preparation method of lithium tetrafluoro (oxalato) phosphate and lithium difluoro (oxalato) phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Under the protection of nitrogen, 18.08g of oxalic acid and 125.0g of diethyl carbonate were added to a dry 1000mL three-necked flask, stirred, and then 32.3g of hexamethyldisilazane was added, and stirred for 30min to make it evenly mixed. Preparation of lithium hexafluorophosphate solution: under the protection of nitrogen, take 38.0 g of lithium hexafluorophosphate and add in batches to 125.0 g of diethyl carbonate, and stir while adding to make it fully dissolved. Set the temperature to 50°C. After the flask reaches the set temperature, slowly add lithium hexafluorophosphate solution dropwise for 3 hours. After the dropwise addition, continue the heat preservation reaction for 2 hours, then lower the temperature to 30°C, use an oil pump to draw negative pressure, control the pressure in the flask to 1000 Pa, keep it for 2 hours, and then fill it with nitrogen to prepare for filtration. Filtrate under positive nitrogen pressure, and select 0.45um polypropylene membra...

Embodiment 2

[0030] Under the protection of nitrogen, add 40.7g of oxalic acid and 125.0g of diethyl carbonate into a dry 1000mL three-necked flask, stir, then add 80.7g of hexamethyldisilazane, stir for 30min to make it evenly mixed. Preparation of lithium hexafluorophosphate solution: under the protection of nitrogen, take 38.0 g of lithium hexafluorophosphate and add in batches to 125.0 g of diethyl carbonate, and stir while adding to make it fully dissolved. Set the temperature to 60°C. After the flask reaches the set temperature, slowly add lithium hexafluorophosphate solution dropwise for 3 hours. After the dropwise addition, continue the heat preservation reaction for 2 hours, then lower the temperature to 30°C, use an oil pump to draw negative pressure, control the pressure in the flask to 1000 Pa, keep it for 2 hours, and then fill it with nitrogen to prepare for filtration. Filtrate under positive nitrogen pressure, and select a 0.45um polypropylene membrane as a microporous filt...

Embodiment 3

[0032] Under the protection of nitrogen, add 22.6g oxalic acid and 125.0g ethylene glycol dimethyl ether into a dry 1000mL three-necked flask, stir, then add 40.4g hexamethyldisilazane, stir for 30min to make it evenly mixed. Preparation of lithium hexafluorophosphate solution: under the protection of nitrogen, take 38.0 g of lithium hexafluorophosphate and add in batches to 125.0 g of diethyl carbonate, and stir while adding to make it fully dissolved. The temperature was set at 75°C, and after the flask reached the set temperature, lithium hexafluorophosphate solution was slowly added dropwise for 4 hours. After the dropwise addition, continue the heat preservation reaction for 5 hours, then lower the temperature to 40°C, use an oil pump to draw negative pressure, control the pressure in the flask to 1000 Pa, keep it for 2 hours, and then fill it with nitrogen to prepare for filtration. Filtrate under positive nitrogen pressure, and select 0.45um polypropylene membrane as th...

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Abstract

The invention discloses a preparation method of lithium tetrafluoro (oxalato) phosphate and lithium difluoro (oxalato) phosphate. The method comprises the following steps: in a nitrogen atmosphere, adding silazane into an oxalic acid solution, uniformly stirring, dropwise adding a lithium hexafluorophosphate solution according to a molar ratio of the dropwise adding amount of lithium hexafluorophosphate to oxalic acid of 1: (0.8-1.2), and reacting to obtain lithium tetrafluoro (oxalato) phosphate; or adding silazane into an oxalic acid solution, dropwise adding the lithium hexafluorophosphatesolution after uniform stirring, wherein the molar ratio of the dropwise adding amount of lithium hexafluorophosphate to oxalic acid is 1: (1.8-2.4), and obtaining lithium difluorobis (oxalate) phosphate after reaction. The reaction route and reaction conditions are safe, environmentally friendly, economical and capable of achieving industrialization, generated by-products are lithium bicarbonateand lithium fluoride, separation is easy, no corrosive gas is generated, and the safety of the whole technological process is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a preparation method of tetrafluorolithium oxalate phosphate and lithium difluorobisoxalate phosphate. Background technique [0002] Electrolyte additives can form SEI films on Li-rich cathodes by electrochemical oxidation prior to solvents. Lithium salt-like compounds have been used as reducible additives in the anode of Li-ion batteries, forming a stable solid electrolyte phase (SEI) not only on the anode but also on the cathode with higher charging voltage. Lithium, lithium bis(oxalate)borate (LiBOB), lithium tetrafluorooxalate phosphate (LTFOP), and lithium, difluoro(oxalate)borate (LiDFOB), can build up a proper SEI layer on the cathode surface, improving the cathode’s electrical chemical properties. The LiBOB-derived SEI layer can alleviate the voltage decay of Li-rich cathodes due to the layer-to-spinel phase transition and enhance their cycle p...

Claims

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Application Information

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IPC IPC(8): C07F9/6571
CPCC07F9/6571
Inventor 万广聪申海鹏孙春胜程梅笑郭营军
Owner 香河昆仑新能源材料股份有限公司
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