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Study on modification of lithium-sulfur battery materials
2019-03-21
来源:亚科官网
Lithium-sulfur battery (Li-S) has high theoretical specific capacity and energy density, as well as low cost and environmental friendliness. It has attracted wide attention of researchers and become one of the most promising high-capacity storage systems. Lithium-sulfur batteries have their own limitations, which limits their commercial applications. At present, lithium-sulfur battery material modification research is one of the keys to improve the performance of all aspects of batteries, improving conductivity, suppressing shuttle effect, reducing lithium electrode corrosion, and thus improving the electrochemical performance of the battery plays an important role.
What is a lithium-sulfur battery?
A lithium-sulfur battery is a lithium battery in which a sulfur element is used as a positive electrode of a battery and lithium metal is used as a negative electrode. At present, the energy density of a lithium-ion battery with a ternary material as a positive electrode will be close to the theoretical value before and after 2020, and it is difficult to exceed 350 Wh/kg. To manufacture a secondary battery of 400 Wh/kg or more, a new lithium battery system needs to be developed. The lithium-sulfur battery using sulfur as the positive electrode material has a theoretical specific capacity of sulfur and a theoretical specific energy of 1,675 mAh/g and 2600 Wh/kg, respectively, which is much higher than the current commercial lithium-ion battery, and the lithium-sulfur battery system may rise. It has become one of the main research directions of high-energy new batteries, providing more ideas and possibilities for the development and exploration of lithium battery.
Lack of lithium-sulfur batteries
The main disadvantages of lithium-sulfur batteries are: lithium polysulfide compounds are dissolved in the electrolyte; sulfur as a non-conductive substance, the conductivity is very poor, which is not conducive to the high rate performance of the battery; the volume of the sulfur is greatly reduced during the charging and discharging process, it may cause battery damage.
In view of the shortcomings of lithium-sulfur batteries, researchers mainly solve the problem through the following technical routes. First, the electrode material is modified, and one or more electronic conductors are added to the sulfur to achieve the purpose of improving conductivity; the second is to design the conductive phase structure to have the ability to adsorb polysulfide and inhibit excessive polysulfide dissolved; the third is to improve the electrolyte system of the battery; the fourth is the protection of the lithium negative electrode. At present, research on modification of lithium-sulfur battery materials is one of the keys to improving the performance of all aspects of batteries.
Related links: lithium sulfur battery
Edited by Suzhou Yacoo Science Co., Ltd.