A phosphate-based high-voltage flame-retardant electrolyte

A phosphate-based, electrolyte technology, used in organic electrolytes, non-aqueous electrolytes, non-aqueous electrolyte batteries, etc., can solve the problems of poor wettability of electrode separators and high viscosity of phosphate esters, and achieve excellent cycle performance, low volatility, and easy The effect of large-scale application

Active Publication Date: 2022-06-03
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the viscosity of phosphate ester itself is high, and its wettability with electrodes and diaphragms is poor, so there are still many problems in practical applications.

Method used

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  • A phosphate-based high-voltage flame-retardant electrolyte
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  • A phosphate-based high-voltage flame-retardant electrolyte

Examples

Experimental program
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Effect test

Embodiment 1

[0031] A phosphate-based high-pressure flame retardant electrolyte, the lithium salts are LiBOB and LiNO 3 , the solvent is trimethyl phosphate, and the diluent is 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether. The preparation method is as follows: trimethyl phosphate and LiBOB, LiNO 3 Weigh and mix according to the molar ratio of 8:1:0.1, stir evenly, and then add 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoroethyl 0.5 times the volume of trimethyl phosphate propyl ether. The electrolyte system was used in NCM 811||Li half-cell for physical properties and electrochemical cycle tests. The test found that the battery can cycle under 4.5V high voltage for 200 cycles and the capacity retention rate is greater than 90%; and the electrolyte is non-flammable of. At the same time, the compatibility of the electrolyte and the graphite negative electrode was also tested, and the 0.005-1.5V cycle test was carried out.

Embodiment 2

[0033] A phosphate-based high-pressure flame-retardant electrolyte, the lithium salt is LiFSI, LiPF 6 , the solvent is triethyl phosphate, and the diluent is bis(2,2,2-trifluoroethyl) ether. The preparation method is as follows: combining triethyl phosphate with LiFSI and LiPF 6 According to the molar ratio of 8:1:0.05, weigh and mix, stir evenly, and then add bis(2,2,2-trifluoroethyl) ether twice the volume of triethyl phosphate. The electrolyte system was used in NCM 811||Li half-cell for physical properties and electrochemical cycle tests. The test found that the battery can cycle under 4.5V high voltage for 200 cycles and the capacity retention rate is greater than 90%; and the electrolyte is non-flammable of. At the same time, the compatibility of the electrolyte and the graphite negative electrode was also tested, and the 0.005-1.5V cycle test was carried out.

Embodiment 3

[0035] A phosphate-based high-pressure flame-retardant electrolyte, the lithium salts are LiDFOB, LiBF 4 , the solvent is trioctyl phosphate, and the diluent is fluoromethyl-1,1,1,3,3,3-hexafluoroisopropyl ether. The preparation method is as follows: combining trioctyl phosphate with LiDFOB and LiBF 4 According to the molar ratio of 8:1:1, weigh and mix, stir evenly, and then add the same volume of fluoromethyl-1,1,1,3,3,3-hexafluoroisopropyl ether as trioctyl phosphate. The electrolyte system was used in NCM 811||Li half-cell for physical property and electrochemical cycle tests. The test found that the battery can cycle under 4.5V high voltage for 200 cycles and the capacity retention rate is greater than 80%; and the electrolyte is non-flammable of. At the same time, the compatibility of the electrolyte and the graphite negative electrode was also tested, and the 0.005-1.5V cycle test was performed.

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Abstract

This patent discloses a high-voltage flame-retardant electrolyte formula, which is applied to lithium-ion secondary batteries. The main feature of the invention is that phosphoric acid ester is used as a solvent component, which forms a solvation structure with lithium salt in a certain ratio, and is dispersed in a fluoroether solvent. Phosphate ester coordinates with lithium ions to form a certain solvation structure, which effectively prevents co-intercalation of graphite with lithium ions. By introducing fluoroether, the viscosity of the electrolyte is reduced, the wettability of the electrolyte is increased, and the thermal and electrochemical stability of the electrolyte are not affected, and the fluoroether is also non-flammable and does not affect the electrolyte flame retardant effect. The electrolyte solution provided by the invention can form a dense and stable protective film on the surface of the positive electrode and the negative electrode, and the capacity retention rate of the NCM 811||Li half-cell after 200 cycles reaches more than 90%, and at the same time, it has good compatibility with graphite. Using this electrolyte can significantly improve the high-voltage cycle stability of the electrolyte and battery safety.

Description

technical field [0001] The invention relates to the technical field of battery preparation, in particular to a phosphate-based high-voltage flame-retardant electrolyte, a lithium battery and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high specific energy, high operating voltage, and long cycle life, and are suitable for consumer electronic products such as mobile phones, tablets, and computers. in the car. At present, most commercial lithium-ion batteries are composed of organic carbonate solvents and lithium salts. However, due to the poor thermal stability of nickel-cobalt-manganese ternary high-voltage materials and the flammability and volatility of carbonate solvents, when the battery is short-circuited or heat accumulated due to collision or other reasons, it is easy to cause thermal runaway, which also This makes the explosion and combustion of electric vehicles occur frequently. [0003] In response to ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/0569H01M10/052H01M10/0525
CPCH01M10/0569H01M10/052H01M10/0525H01M2300/0028Y02E60/10
Inventor 张锁江贾梦敏张兰郭亚伟
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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