Lithium-sulfur battery electrolyte and preparation method thereof and battery using lithium-sulfur battery electrolyte

A lithium-sulfur battery and electrolyte technology, which is applied in the field of preparation of the electrolyte, can solve the problems that cycle performance and specific capacity cannot be taken into account, polysulfide dissolution cannot be prevented, and the effect of improving the specific capacity of the cycle performance battery is not obvious. , to achieve the effects of improving Coulombic efficiency and cycle performance, improving discharge specific capacity and cycle stability, and improving capacity retention

Active Publication Date: 2018-03-09
深圳启辰新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, many additives cannot take into account the improvement of cycle performance and specific capacity while improving Coulombic efficiency.
At present, the additives of lithium-sulfur batteries are mainly LiNO 3 and P 2 S 5 , it has a significant effect on improving the Coulombic efficiency of the battery, but it has no obvious effect on improving the cycle performance and specific capacity of the battery, because it only forms an SEI film on the surface of the lithium negative electrode to protect the lithium negative electrode, and cannot prevent multiple Dissolution of sulfide

Method used

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  • Lithium-sulfur battery electrolyte and preparation method thereof and battery using lithium-sulfur battery electrolyte
  • Lithium-sulfur battery electrolyte and preparation method thereof and battery using lithium-sulfur battery electrolyte
  • Lithium-sulfur battery electrolyte and preparation method thereof and battery using lithium-sulfur battery electrolyte

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] (1) Electrolyte and its preparation

[0031] in an argon atmosphere glove box (H 2 O<0.1ppm), the organic solvent is mixed with LiTFSI (1.0M) at a volume ratio of 1,3-dioxolane (DOL): ethylene glycol dimethyl ether (DME) = 1:1, and the total mass of 2 % of dimethyl diselenide, fully stirred evenly to obtain the lithium-sulfur battery electrolyte of the present invention.

[0032] (2) Preparation of positive pole piece

[0033] Mix the sulfur / activated carbon composite material, carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 8:1:1, then add an appropriate amount of N-methylpyrrolidone (NMP) dropwise, and then perform ball milling Mixing, wherein the number of revolutions of the ball mill is 200 rpm, and the ball milling time is 4 hours. Spread the ball-milled slurry evenly on the aluminum foil, and perform vacuum drying at a drying temperature of 60 degrees Celsius for 4 hours to obtain the positive electrode material.

[0034] (3) Pre...

Embodiment 2-8

[0041] Except the parameters in the following table, other parameters and preparation method are the same as in Example 1.

[0042] Table 1 Example 2-8

[0043]

[0044]

[0045] The test result of table 2 embodiment and comparative example

[0046]

[0047] Embodiments 1 to 8 are compared with comparative example 1, and comparative example 1 is under the discharge rate of 0.5C, and the first cycle discharge specific capacity is

[0048] 602mAh / g, which is 214mAh / g-363mAh / g less than the first-cycle discharge specific capacity in Examples 1 to 8, and the cycle performance is also 29.7%-55.5% lower than that in Examples 1-8, and the Coulombic efficiency is also low 0.8% to 2%, it can be seen that the selenide additive significantly improves the discharge specific capacity, cycle performance and coulombic efficiency of the battery.

Embodiment 9

[0050] (1) Preparation of electrolyte

[0051] in an argon atmosphere glove box (H 2 O3 CF 3 (0.5M) and mix, add 0.5% dimethyl diselenide and 0.5% lithium nitrate in total mass, and fully stir evenly to obtain the lithium-sulfur battery electrolyte of the present invention.

[0052] (2) Preparation of positive electrode sheet for lithium-sulfur battery

[0053] Mix the carbon-coated lithium sulfide composite material, carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 8:1:1, then add an appropriate amount of N-methylpyrrolidone (NMP) dropwise, and then carry out Ball milling the mixture, wherein the number of revolutions of the ball mill is 200 rpm, and the ball milling time is 4 hours. Spread the ball-milled slurry evenly on the aluminum foil, and carry out vacuum drying at a drying temperature of 60 degrees Celsius and a drying time of 4 hours to obtain the positive electrode material. This process is completed in a drying room with a drying de...

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Abstract

The invention discloses a lithium-sulfur battery electrolyte and a preparation method thereof; the lithium-sulfur battery electrolyte comprises a selenide additive; the selenide additive is dimethylselenide, dimethyldiselenide, dimethyltriselenide, diphenyl methylselenide, diphenyl diselenide, acetic selenide, propionic selenide or propionic diselenide, or of at least two or more of their group; the selenide additive accounts for 0.1-10% by weight of the electrolyte. The electrolyte prepared by using the preparation method and a battery using the electrolyte have the advantages that internal resistance of the battery can be effectively reduced, a passivated layer is formed on the surface of an electrode of the battery and the battery gains increased discharge specific capacity, cycle performance and coulombic efficiency.

Description

technical field [0001] The invention relates to a lithium-sulfur battery electrolyte containing selenium ether additives. The invention also relates to a method for preparing the electrolyte. The invention also relates to a battery using the electrolyte. Background technique [0002] With the rapid development of related technologies such as mobile communications, portable electronic devices, electric vehicles and energy storage devices, higher and higher requirements are placed on battery performance, especially specific capacity, energy density, cycle life and rate performance. . Therefore, it is of great strategic significance to develop new lithium-ion secondary batteries with high performance, low cost and environmental friendliness. The performance and price of cathode materials are the bottlenecks that restrict the further development of lithium-ion batteries to high energy density, long life and low cost. For example, the existing LiFePO 4 , LiMn 2 o 4 Due to ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/052H01M10/0567
CPCH01M10/052H01M10/0567Y02E60/10
Inventor 徐辉陈国华覃旭松
Owner 深圳启辰新能源科技有限公司
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