Method for stabilizing color and luster, moisture and fluohydric acid content of non-aqueous electrolyte

Abstract

The invention provides a method for stabilizing the color and luster, the water content and the hydrofluoric acid content of a nonaqueous electrolyte at a high temperature of between 50 and 70 DEG C. The method is to add a silicon amine compound and a phosphorous acid ester compound into the nonaqueous electrolyte, wherein the addition of the silicon amine compound and the phosphorous acid ester compound is 0.01 to 3 percent of the weight of the electrolyte. The compounds can effectively inhibit increase of the water content and the hydrofluoric acid content of the electrolyte and maintain stable quality of the electrolyte.

Description

technical field

[0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for stabilizing the color, moisture and hydrofluoric acid content of a non-aqueous electrolyte. Background technique

[0002] The electrolyte is an important part of the lithium-ion battery. It is an ionic conductor that conducts electricity between the positive and negative electrodes of the battery. Its own performance and the interface conditions formed with the positive and negative electrodes greatly affect the performance of the battery. An excellent non-aqueous electrolyte for lithium-ion batteries should meet the following requirements. (1) Good chemical stability, no chemical reaction with positive and negative active materials and current collectors (generally aluminum foil and copper foil) in the battery; (2) Wide electrochemical stability window; (3) High ionic conductivity, Low electronic conductivity; (4) Good film-forming properties, forming...

Examples

Embodiment 1

[0019] Prepare non-aqueous electrolyte 1M LiPF in an argon-filled glove box (moisture 6 , EC: DMC: EMC=1: 1: 1 (mass ratio), four parts in total, each part of 1L, taking the original sample without additives as the standard, adding hexamethyldisilazane and ethylene oxide respectively in the remaining three samples Tributyl phosphate 0.02%, 0.4%, 1%, after sealing, conduct a comparative test at 50°C to detect the content and color of water and hydrofluoric acid, the results are shown in the table below.

[0020]

[0021]

[0022] It can be seen from the above table that after adding an appropriate amount of hexamethyldisilazane and tributyl phosphite to the non-aqueous electrolyte, the content of water and hydrofluoric acid remains stable and the color is stable compared with the original state without addition.

Embodiment 2

[0024] Prepare non-aqueous electrolyte 1M LiPF in an argon-filled glove box (moisture 6 , EC:DMC:EMC=1:1:1 (mass ratio), a total of three parts, each 1L, with no additives as the standard, the remaining two samples were added 0.5% of hexamethyldisilamine alkane and tributyl phosphite, 0.5% hexaethyldisilazane and triphenyl phosphite, after sealing, conduct a comparative test at 50°C to detect the content and color of moisture and hydrofluoric acid, and the results See the table below.

[0025]

[0026] It can be seen from the above table that after adding an appropriate amount of silicon amine compounds and phosphite compounds to the non-aqueous electrolyte, compared with the original without addition, the content of water and hydrofluoric acid remains stable, and the color is stable.

Embodiment 3

[0028] Prepare non-aqueous electrolyte 1M LiPF in an argon-filled glove box (moisture 6 , EC:DMC:EMC=1:1:1 (mass ratio), a total of six parts, each 1L, with no additives as the standard (three parts), the remaining three samples were added 0.3% Hexa Disilazane and tributyl phosphite, after sealing, conduct a comparative test at 50°C to 70°C to detect the content and color of water and hydrofluoric acid, the results are shown in the table below.

[0029]

[0030] It can be seen from the above table that after adding an appropriate amount of silicon amine compounds and phosphite compounds to the non-aqueous electrolyte, compared with the original solution without adding it, the moisture and The content of hydrofluoric acid remains stable and the color does not change.

technical field

[0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for stabilizing the color, moisture and hydrofluoric acid content of a non-aqueous electrolyte. Background technique

[0002] The electrolyte is an important part of the lithium-ion battery. It is an ionic conductor that conducts electricity between the positive and negative electrodes of the battery. Its own performance and the interface conditions formed with the positive and negative electrodes greatly affect the performance of the battery. An excellent non-aqueous electrolyte for lithium-ion batteries should meet the following requirements. (1) Good chemical stability, no chemical reaction with positive and negative active materials and current collectors (generally aluminum foil and copper foil) in the battery; (2) Wide electrochemical stability window; (3) High ionic conductivity, Low electronic conductivity; (4) Good film-forming properties, forming...

Examples

Embodiment 1

[0019] Prepare non-aqueous electrolyte 1M LiPF in an argon-filled glove box (moisture 6 , EC: DMC: EMC=1: 1: 1 (mass ratio), four parts in total, each part of 1L, taking the original sample without additives as the standard, adding hexamethyldisilazane and ethylene oxide respectively in the remaining three samples Tributyl phosphate 0.02%, 0.4%, 1%, after sealing, conduct a comparative test at 50°C to detect the content and color of water and hydrofluoric acid, the results are shown in the table below.

[0020]

[0021]

[0022] It can be seen from the above table that after adding an appropriate amount of hexamethyldisilazane and tributyl phosphite to the non-aqueous electrolyte, the content of water and hydrofluoric acid remains stable and the color is stable compared with the original state without addition.

Embodiment 2

[0024] Prepare non-aqueous electrolyte 1M LiPF in an argon-filled glove box (moisture 6 , EC:DMC:EMC=1:1:1 (mass ratio), a total of three parts, each 1L, with no additives as the standard, the remaining two samples were added 0.5% of hexamethyldisilamine alkane and tributyl phosphite, 0.5% hexaethyldisilazane and triphenyl phosphite, after sealing, conduct a comparative test at 50°C to detect the content and color of moisture and hydrofluoric acid, and the results See the table below.

[0025]

[0026] It can be seen from the above table that after adding an appropriate amount of silicon amine compounds and phosphite compounds to the non-aqueous electrolyte, compared with the original without addition, the content of water and hydrofluoric acid remains stable, and the color is stable.

Embodiment 3

[0028] Prepare non-aqueous electrolyte 1M LiPF in an argon-filled glove box (moisture 6 , EC:DMC:EMC=1:1:1 (mass ratio), a total of six parts, each 1L, with no additives as the standard (three parts), the remaining three samples were added 0.3% Hexa Disilazane and tributyl phosphite, after sealing, conduct a comparative test at 50°C to 70°C to detect the content and color of water and hydrofluoric acid, the results are shown in the table below.

[0029]

[0030] It can be seen from the above table that after adding an appropriate amount of silicon amine compounds and phosphite compounds to the non-aqueous electrolyte, compared with the original solution without adding it, the moisture and The content of hydrofluoric acid remains stable and the color does not change.

Images