A kind of non-aqueous electrolyte and preparation method thereof and application in lithium ion battery

Abstract

The invention discloses a nonaqueous electrolytic solution, a preparation method thereof and an application in a lithium ion battery. The non-aqueous electrolytic solution comprises lithium salt, organic solvent and additive, and described organic solvent comprises chain carbonate, cyclic carbonate, silane-substituted cyclic carbonate and fluorine-containing ether diluent; Said additive comprises lithium difluorophosphate , cyclic sulfate, tris(2,2,2-trifluoroethyl) phosphate. The lithium-ion battery prepared by the non-aqueous electrolyte of the present invention can improve the fast charging rate performance and cycle performance on the basis of maintaining a conductivity of more than 8.5 mS / cm, and the capacity retention rate after 500 cycles can still be 92% at the same time. % or more, it has excellent battery fast charging performance and cycle performance, and the self-extinguishing time is below 2s / g, with excellent flame retardancy, which can further improve the safety performance of lithium-ion batteries and can be widely used in lithium-ion batteries. battery.

Description

technical field

[0001] The invention relates to the technical field of lithium-ion batteries, and more specifically, relates to a non-aqueous electrolyte and its application in lithium-ion batteries. Background technique

[0002] Due to its high reversible specific capacity, low price and environmental friendliness, high-nickel materials have become a research hotspot in materials and energy disciplines, and are also the preferred materials for future high-energy-density power batteries. However, some inherent disadvantages, such as battery During the cycling process, the structural stability of the material is poor, and high-rate charging is prone to lithium precipitation, which can easily lead to battery safety issues, which greatly limits its wide application in various fields. When a lithium-ion power battery with a conventional electrolyte system is charged quickly at a high current, the electrode interface impedance increases, and lithium ions cannot be effectively emb...

Examples

Embodiment 1

[0044] A non-aqueous electrolyte comprising lithium salts, organic solvents and additives,

[0045] The organic solvent includes: 20% diethyl carbonate DEC, 20% ethyl methyl carbonate EMC, 20% ethylene carbonate EC, 10% trimethylsilyl substituted propylene carbonate TMSPC and 30% tetrafluoroethylene Base-tetrafluoropropyl ether HFE;

[0046] Lithium hexafluorophosphate whose lithium salt is 2mol / L;

[0047] Based on the total mass of the electrolyte as 100%, the additives include 1.0% lithium difluorophosphate LiPO 2 f 2 , 1.0% vinyl sulfate DTD, 3.0% tris(2,2,2-trifluoroethyl)phosphate TFEP.

[0048] The preparation steps of non-aqueous electrolyte are as follows:

[0049] S1. Dewatering of raw materials: In an anhydrous and oxygen-free glove box, use a 4A (5A) water separation sieve to dewater the solvent, diluent, and additives. The treatment time is 20 to 30 hours, and the water content is less than 10ppm. Solvents, thinners and additives;

[0050] S2. Preparation of...

Embodiment 2

[0055] A non-aqueous electrolyte comprising lithium salts, organic solvents and additives,

[0056] The organic solvent includes: 25% diethyl carbonate DEC, 25% ethyl methyl carbonate EMC, 20% ethylene carbonate EC, 10% trimethylsilyl substituted butylene carbonate TMSBC and 20% tetrafluoroethylene Ethyl-tetrafluoropropyl ether HFE;

[0057] Lithium hexafluorophosphate whose lithium salt is 2mol / L;

[0058] Based on the total mass of the electrolyte as 100%, the additives include 1.0% lithium difluorophosphate LiPO 2 f 2 , 1.0% vinyl sulfate DTD, 3.0% tris(2,2,2-trifluoroethyl)phosphate TFEP.

[0059] The preparation steps of the non-aqueous electrolyte are as in Example 1.

[0060] Battery assembly and testing:

[0061] Inject the above electrolyte into the dried 2000mAh LiNi 0.8 co 0.1 mn 0.1 o 2 / Graphite soft-packed batteries, the batteries are routinely divided after being placed at 45°C, formed by high-temperature fixtures and sealed twice.

[0062] Then the b...

Embodiment 3

[0064] A non-aqueous electrolyte comprising lithium salts, organic solvents and additives,

[0065] The organic solvent includes: 25% diethyl carbonate DEC, 25% ethyl methyl carbonate EMC, 20% ethylene carbonate EC, 10% trimethylsilyl substituted propylene carbonate TMSPC and 20% tetrafluoroethylene Base-tetrafluoropropyl ether HFE;

[0066] Lithium hexafluorophosphate whose lithium salt is 2mol / L;

[0067] Based on the total mass of the electrolyte as 100%, the additives include 1.0% lithium difluorophosphate LiPO 2 f 2 , 1.0% vinyl sulfate DTD, 3.0% tris(2,2,2-trifluoroethyl)phosphate TFEP.

[0068] The preparation steps of the non-aqueous electrolyte are as in Example 1.

[0069] Battery assembly and testing:

[0070] Inject the above electrolyte into the dried 2000mAh LiNi 0.8 co 0.1 mn 0.1 o 2 / Graphite soft-packed batteries, the batteries are routinely divided after being placed at 45°C, formed by high-temperature fixtures and sealed twice.

[0071] Then the b...

technical field

[0001] The invention relates to the technical field of lithium-ion batteries, and more specifically, relates to a non-aqueous electrolyte and its application in lithium-ion batteries. Background technique

[0002] Due to its high reversible specific capacity, low price and environmental friendliness, high-nickel materials have become a research hotspot in materials and energy disciplines, and are also the preferred materials for future high-energy-density power batteries. However, some inherent disadvantages, such as battery During the cycling process, the structural stability of the material is poor, and high-rate charging is prone to lithium precipitation, which can easily lead to battery safety issues, which greatly limits its wide application in various fields. When a lithium-ion power battery with a conventional electrolyte system is charged quickly at a high current, the electrode interface impedance increases, and lithium ions cannot be effectively emb...

Examples

Embodiment 1

[0044] A non-aqueous electrolyte comprising lithium salts, organic solvents and additives,

[0045] The organic solvent includes: 20% diethyl carbonate DEC, 20% ethyl methyl carbonate EMC, 20% ethylene carbonate EC, 10% trimethylsilyl substituted propylene carbonate TMSPC and 30% tetrafluoroethylene Base-tetrafluoropropyl ether HFE;

[0046] Lithium hexafluorophosphate whose lithium salt is 2mol / L;

[0047] Based on the total mass of the electrolyte as 100%, the additives include 1.0% lithium difluorophosphate LiPO 2 f 2 , 1.0% vinyl sulfate DTD, 3.0% tris(2,2,2-trifluoroethyl)phosphate TFEP.

[0048] The preparation steps of non-aqueous electrolyte are as follows:

[0049] S1. Dewatering of raw materials: In an anhydrous and oxygen-free glove box, use a 4A (5A) water separation sieve to dewater the solvent, diluent, and additives. The treatment time is 20 to 30 hours, and the water content is less than 10ppm. Solvents, thinners and additives;

[0050] S2. Preparation of...

Embodiment 2

[0055] A non-aqueous electrolyte comprising lithium salts, organic solvents and additives,

[0056] The organic solvent includes: 25% diethyl carbonate DEC, 25% ethyl methyl carbonate EMC, 20% ethylene carbonate EC, 10% trimethylsilyl substituted butylene carbonate TMSBC and 20% tetrafluoroethylene Ethyl-tetrafluoropropyl ether HFE;

[0057] Lithium hexafluorophosphate whose lithium salt is 2mol / L;

[0058] Based on the total mass of the electrolyte as 100%, the additives include 1.0% lithium difluorophosphate LiPO 2 f 2 , 1.0% vinyl sulfate DTD, 3.0% tris(2,2,2-trifluoroethyl)phosphate TFEP.

[0059] The preparation steps of the non-aqueous electrolyte are as in Example 1.

[0060] Battery assembly and testing:

[0061] Inject the above electrolyte into the dried 2000mAh LiNi 0.8 co 0.1 mn 0.1 o 2 / Graphite soft-packed batteries, the batteries are routinely divided after being placed at 45°C, formed by high-temperature fixtures and sealed twice.

[0062] Then the b...

Embodiment 3

[0064] A non-aqueous electrolyte comprising lithium salts, organic solvents and additives,

[0065] The organic solvent includes: 25% diethyl carbonate DEC, 25% ethyl methyl carbonate EMC, 20% ethylene carbonate EC, 10% trimethylsilyl substituted propylene carbonate TMSPC and 20% tetrafluoroethylene Base-tetrafluoropropyl ether HFE;

[0066] Lithium hexafluorophosphate whose lithium salt is 2mol / L;

[0067] Based on the total mass of the electrolyte as 100%, the additives include 1.0% lithium difluorophosphate LiPO 2 f 2 , 1.0% vinyl sulfate DTD, 3.0% tris(2,2,2-trifluoroethyl)phosphate TFEP.

[0068] The preparation steps of the non-aqueous electrolyte are as in Example 1.

[0069] Battery assembly and testing:

[0070] Inject the above electrolyte into the dried 2000mAh LiNi 0.8 co 0.1 mn 0.1 o 2 / Graphite soft-packed batteries, the batteries are routinely divided after being placed at 45°C, formed by high-temperature fixtures and sealed twice.

[0071] Then the b...

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