Low temperature functional electrolyte of lithium-ion secondary battery and preparation method thereof

A secondary battery and lithium-ion technology, applied in secondary batteries, circuits, electrical components, etc., can solve the problems of weakening the conductivity, diffusion coefficient, and impoverishment of the electrolyte, and achieve the goal of improving poor low-temperature solubility and low-temperature performance Effect

Inactive Publication Date: 2010-02-10
万向电动汽车有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] On the one hand, the above-mentioned electrolyte uses a high content of film-forming solvent EC. Due to the high melting point of EC, it is easy to cause the crystallization of lithium salt at low temperature, resulting in the lack of lithium ions in the electrolyte; on the other hand, due to the use of LiPF with poor low-temperature performance 6 As a single conductive lithium salt, it also seriously weakens the conductivity and diffusion coefficient of the electrolyte, these two factors greatly affect the current Li 4 Ti 5 o 12 Low temperature performance of secondary batteries, especially low temperature rate and cycle performance

Method used

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  • Low temperature functional electrolyte of lithium-ion secondary battery and preparation method thereof
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  • Low temperature functional electrolyte of lithium-ion secondary battery and preparation method thereof

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Embodiment 1

[0044] The first step is to use a rotary evaporator to distill and purify the organic solvents PC, EMC and EA at 25°C to remove trace water in them, and then use 4A molecular sieves to deeply absorb trace water at 40°C. This operation is repeated three times until the impurity and water content are less than 0.005%. Then PC, EMC, and EA were mixed with ternary solvents, and a certain amount of PC, EMC, and EA were weighed with a microanalytical electronic balance, wherein the mass ratio of the three was 3:5:3, and 100ml was measured with a graduated cylinder (250ml). Pour the mixed electrolyte into the grinding bottle. All processes of electrolyte preparation are carried out in a glove box filled with high-purity argon;

[0045] The second step is to weigh 10g of LiPF with a microanalytical electronic balance in the glove box at 25°C. 6 and 2g LiODFB. Then add it to the above-mentioned ternary mixed solvent (in the grinding bottle), fully stir evenly, until the solution is ...

Embodiment 2

[0049] The first step is to use a rotary evaporator to distill and purify the organic solvents PC, EMC, and THF at 25°C to remove trace water in them, and then use 4A molecular sieves to deeply absorb trace water at 40°C. This operation is repeated three times until the impurity and water content are less than 0.005%. Then PC, EMC, and THF are mixed with ternary solvents, and a certain amount of PC, EMC, and THF are each weighed with a microanalytical electronic balance, wherein the mass ratio of the three is 5:3:2, and 100ml is measured with a graduated cylinder (250ml) Pour the mixed electrolyte into the grinding bottle. All processes of electrolyte preparation are carried out in a glove box filled with high-purity argon;

[0050] The second step is to weigh 8g of LiPF with a microanalytical electronic balance in the glove box at 25°C 6 and 4g LiBF 4 . Then add it to the above-mentioned ternary mixed solvent (in the grinding bottle), fully stir evenly, until the solution...

Embodiment 3

[0054] The first step is to use a rotary evaporator to distill and purify the organic solvents PC, DEC, and EA at 25°C to remove trace water in them, and then use 4A molecular sieves to deeply absorb trace water at 40°C. This operation is repeated three times until the impurity and water content are less than 0.005%. Then PC, DEC, and EA were mixed with ternary solvents, and a certain amount of PC, DEC, and EA were weighed with a microanalytical electronic balance, and the mass ratio of the three was 4:3:3, and 100ml was measured with a graduated cylinder (250ml). Pour the mixed electrolyte into the grinding bottle. All processes of electrolyte preparation are carried out in a glove box filled with high-purity argon;

[0055] The second step is to weigh 3g of LiPF with a microanalytical electronic balance in the glove box at 25°C 6 and 6g LiN(SO 2 CF 3 ) 2 . Then add it to the above-mentioned ternary mixed solvent (in the grinding bottle), fully stir evenly, until the so...

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Abstract

The invention mainly relates to a method for preparing low temperature functional electrolyte of a lithium titanate (Li4Ti5O12) lithium-ion secondary battery. The functional electrolyte has the advantage that the electrolyte is suitable for high multiplying power exertion of lithium titanate material at the low temperature (-20 DEG C), thus having extreme property. The method comprises: compounding commercial electrolyte lithium salt LiPF6 and lithium salts (such as LiBF4, LiN(SO2CF3) 2 and LiODFB) with excellent low temperature property, and optimizing an electrolyte low temperature system byreducing or abandoning film-forming solvent EC with poor low temperature property and increasing low boiling point solvents such as PC, EA, THF and the like with the excellent low temperature property aiming at the characteristic of no SEI film of the Li4Ti5O12 battery. Meanwhile, a small quantity of additive is added to stabilize the interface stability of the lithium salts.

Description

technical field [0001] The invention relates to a lithium-ion battery electrolyte system, in particular to a low-temperature functional electrolyte for a lithium-ion secondary battery whose negative electrode material is lithium titanate and a preparation method thereof. Background technique [0002] In recent years, due to the pressure of environmental pollution and energy shortage, countries are forced to find new green, environmentally friendly and sustainable energy sources. The green, high-energy and environmentally friendly lithium-ion battery that appeared in the 1990s has become one of the most eye-catching power sources due to its high energy density, long cycle life, and high operating voltage. Spinel lithium titanate (Li 4 Ti 5 o 12 ) is a stress-free insertion material that does not change its structure during charging and discharging. It has good cycle performance, a good charging and discharging platform, high specific capacity, and is concentrated in the pl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/40H01M10/38
Inventor 李凡群李明刘昊邓龙征
Owner 万向电动汽车有限公司
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