Lithium-sulfur (Li-S) batteries have been considered as a promising candidate for next-generation energy storage devices, owing to the extremely high theoretical specific capacity and energy density of sulfur. However, the shuttle effect of lithium polysulfide hampered its commercial application. Recently, more and more attentions have been focused on designing the modified separator with physical and chemical absorption of polysulfide.
In this work, Ca(OH)2 and acetylene black (AB) had been successfully used to design a functional separator for Li-S batteries. The results indicated that Ca(OH)2-AB coated separator could effectively constrain the shuttle effect of polysulfides. In Figure 1, the first upper plateau discharge capacity is 410 mA h g-1 approaching 97.8% of the theoretical value (419 mA h g-1) after coating Ca(OH)2 and AB into common separator, indicating that the polysulfide diffusion is effectively limited. After 100 cycles, the batteries with Ca(OH)2-AB coated separator remains 82.3% of the theoretical value, while the batteries with AB coated and common separators only retain 65.6% and 38.7%. The enhanced upper plateau capacity demonstrates that Ca(OH)2 can effectively trap the polysufides and inhabit the shuttle effect.
Acknowledgements
Financial support from the National Science Foundation of China (No. 51272017) is gratefully appreciated.
Notes
a State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical University of Chemical Technology, Beijing 100029, People’s Republic of China.
* E-mail: huangyq@mail.buct.edu.cn; Fax: +86 10 6443 8266; Tel: +86 10 6443 8266.
Figure 1. Upper plateau discharge capacities of batteries employing different separators.