Li-S battery is one of the hottest spots of international research in energy storage field owing to its high energy density and low cost. However, the practical application of Li-S battery is still hindered by the rapid capacity fading during cycling due to the shuttle effect, disproportionation of polysulfide, and the decomposition of electrolyte and lithium dendrite.
An energy storage technology research team led by Prof. ZHANG Huamin, Prof. LI Xianfeng and Associate Prof. ZHANG Hongzhang in Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences proposed a new lithium-sulfur (Li-S) battery electrolyte.
In order to suppress the disproportionation of polysulfide, they added a new kind of electrolyte additive, including a large size cation to complex and stabilize polysulfide in the electrolyte based on the hard and soft acids and bases (HSAB) theory.
This newly proposed electrolyte enables more stable capability and a longer cycle life for Li-S battery: 5000 mAh Li-S batteries (soft package type) can achieve an initial specific energy over 300 Wh/kg and can maintain almost 70% after 100 charge/discharge cycles at 1/20 C.
The schematic principle of MEP +complexation in Li-S battery electrolyte. (Image by CHEN Yuqing)
This finding is believed to shed light on the further development of Li-S batteries.
Their work was published in Advanced Functional Materials.
The above research was supported by DICP, National Natural Science Foundation of China, Youth Innovation Promotion Association of CAS, and Dalian Science and Technology Star Program.
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