Inexhaustible natural celluloses in advanced Li-S batteries: a review

Lithium-sulfur batteries (LSBs) have long been regarded as a promising alternative to lithium-ion batteries (LIBs) due to their overwhelming energy density of ca. five-fold to that of the state-of-the-art LIBs. However, the further development of LSBs is hampered by several obstacles including the insulating nature of sulfides, volumetric expansion of active materials, shuttling effect of polysulfides, and growth of lithium dendrites. Cellulose, the most abundant biomass on earth, presents abundant hydroxyl groups, high mechanical modulus, and considerable porous surface, which are highly desirable for tackling the aforementioned issues. Notably, the high carbon content in celluloses, originating mainly from CO2 in the atmosphere, can be properly utilized after carbonization as conductive scaffolds, meeting the new demands for materials on the way to "carbon neutrality". In this review, we summarize the recent progress of LSBs prepared with cellulosic materials including sulfuric cathodes, functional interlayers, battery separators, and binders. The underlying mechanisms of cellulosic materials for the enhancement in electrochemical behaviors are analyzed and elaborated insightfully. Eventually, an outlook on the future directions of celluloses in LSBs is also provided.