Understanding the Advantageous Features of Bacterial Cellulose-Based Separator in Li-S Battery

Separator is a critical component of lithium-sulfur (Li-S) battery, and the property of separator influences the battery performance significantly. Cellulose-based separator is emerging as a promising alternative to the traditional polyolefin separator used in Li-S battery. Although the excellent battery performance of various cellulose-based separators is shown, a comprehensive understanding of the advantageous features of bacterial cellulose (BC)-based separator in Li-S battery still is lacking. In this work, models of BC separators with different thicknesses are prepared and compared with polypropylene separators in terms of their electrochemical performance. The results show that the BC separator exhibits favorable electrolyte affinity, improved lithium-ion transport, suppressed shuttling of soluble polysulfides, and inhibited the formation of lithium dendrites. The combination of these unique characters of BC separator endows it with excellent battery performance. These results provide insight into the use and design of functional cellulose-based separators in advanced secondary batteries.