Lithium ion battery electrolyte and preparation method thereof

A lithium-ion battery and electrolyte technology, applied in the field of lithium-ion batteries, can solve problems such as the effect of reducing impedance, battery appearance, and increasing impedance

Inactive Publication Date: 2019-07-23
SUNWODA ELECTRIC VEHICLE BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Lithium difluorophosphate can be used as an additive to the electrolyte of secondary lithium-ion batteries. Its function is to prolong the cycle period of the battery by delaying the decomposition of electrolytic salts, such as lithium hexafluorophosphate. At the same time, lithium difluorophosphate can also reduce impedance as an electrolyte, but in In practical applications, in order to take into account all aspects of the performance of the battery, it is often necessary to add a variety of different additives to the electrolyte, and in the electrolyte compounded with various additives, the impedance reduction effect of lithium difluorophosphate is affected to a certain extent , and sometimes even increase the impedance, causing the battery to have a risk of lithium precipitation
[0003] In order to overcome the above problems, the present invention provides a new type of electrolyte, which can prevent the ability of lithium difluorophosphate to reduce impedance from being inhibited, thereby improving the rate performance and cycle performance of the battery

Method used

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  • Lithium ion battery electrolyte and preparation method thereof
  • Lithium ion battery electrolyte and preparation method thereof
  • Lithium ion battery electrolyte and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] (1) Preparation of electrolyte:

[0018] In a glove box filled with argon (moisture content<0.1ppm, oxygen content<0.1ppm), ethylene carbonate and diethyl carbonate were mixed uniformly at a mass ratio of 1:2 and stirred continuously, and added to the mixed solvent Slowly add 1.0mol / L lithium hexafluorophosphate, and then add electrolyte additive with a mass fraction of 5.0%, wherein the ratio of lithium difluorophosphate: TMSB: VC: TMSP is 1.0~1.5:1:1:1, stir until completely dissolved , that is, the electrolyte solution of this embodiment is obtained.

[0019] (2) Preparation of lithium ion battery:

[0020] Using NCM811 as the positive electrode active material and graphite as the negative electrode active material, add a conductive agent, a binder and a solvent and mix them well, and then coat them on aluminum foil and copper foil respectively, and then dry, roll, and shear. Positive and negative pole pieces. The positive and negative pole pieces and the polyprop...

Embodiment 2

[0022] (1) Preparation of electrolyte:

[0023] In a glove box filled with argon (moisture content < 0.1ppm, oxygen content < 0.1ppm), mix ethylene carbonate and diethyl carbonate in a mass ratio of 1:2 and stir continuously, slowly add to the mixed solvent Add 1.0mol / L lithium hexafluorophosphate, and then add 5.0% of the electrolyte additive in the total mass fraction of the electrolyte, wherein the ratio of lithium difluorophosphate: TMSB: VC: TMSP is 1.50~1.55:1:1:1, and stir until Dissolve completely, promptly obtain the electrolyte solution of this embodiment.

[0024] (2) Preparation of lithium ion battery:

[0025] Using NCM811 as the positive electrode active material and graphite as the negative electrode active material, add a conductive agent, a binder and a solvent to fully stir and mix them evenly, and then coat them on aluminum foil and copper foil, dry them, roll them, and cut them to obtain a positive electrode. , Negative pole piece. The positive and negat...

Embodiment 3

[0027] (1) Preparation of electrolyte:

[0028] In a glove box filled with argon (moisture content < 0.1ppm, oxygen content < 0.1ppm), mix ethylene carbonate and diethyl carbonate in a mass ratio of 1:2 and stir continuously, slowly add to the mixed solvent Add 1.0 mol / L lithium hexafluorophosphate, and then add 5.0% electrolyte additives accounting for the total mass fraction of the electrolyte, wherein the ratio of lithium difluorophosphate: TMSB: VC: TMSP is 2.0~2.5:1:1:1, and stir until Dissolve completely, promptly obtain the electrolyte solution described in this embodiment.

[0029] (2) Preparation of lithium ion battery:

[0030] Using NCM811 as the positive electrode active material and graphite as the negative electrode active material, add a conductive agent, a binder and a solvent to fully stir and mix them evenly, and then coat them on aluminum foil and copper foil, dry them, roll them, and cut them to obtain a positive electrode. , Negative pole piece. The pos...

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Abstract

The invention discloses a lithium ion battery electrolyte and a preparation method thereof. The electrolyte comprises a non-aqueous organic solvent, lithium salt and an additive; the additive comprises lithium difluorophosphate and one or multiple kinds of tris (trimethyl silane) boric acid ester (TMSB), vinylene carbonate (VC) and tris (trimethylsilyl) phosphite ester (TMSP), and the lithium difluorophosphate is jointly used with one or more of tris (trimethyl silane) boric acid ester (TMSB), vinylene carbonate (VC) and tris (trimethylsilyl) phosphite ester, so that the capability of reducingthe impedance of the lithium difluorophosphate can be avoided from being influenced, further, the rate performance and the cycling performance of the battery can be improved, and the preparation process of the electrolyte is simple.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery electrolyte and a preparation method thereof. Background technique [0002] Lithium difluorophosphate can be used as an additive to the electrolyte of secondary lithium-ion batteries. Its function is to prolong the cycle period of the battery by delaying the decomposition of electrolytic salts, such as lithium hexafluorophosphate. At the same time, lithium difluorophosphate can also reduce impedance as an electrolyte, but in In practical applications, in order to take into account all aspects of the performance of the battery, it is often necessary to add a variety of different additives to the electrolyte, and in the electrolyte compounded with various additives, the impedance reduction effect of lithium difluorophosphate is affected to a certain extent , and sometimes even increase the impedance, causing the battery to have a risk of lithium ...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/0566H01M10/0525
CPCH01M10/0525H01M10/0566H01M10/0567H01M2300/0025Y02E60/10
Inventor 孟凡星安黎张友为孙佩佩张耀
Owner SUNWODA ELECTRIC VEHICLE BATTERY CO LTD
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