Highly dispersed cobalt clusters/nanoparticles embedded in cellulose nanocrystal derived carbon aerogel as efficient sulfur host for high performance lithium sulfur batteries

Exploring multifunctional sulfur host materials with high immobilization ability and catalytic activity is of great significance for realizing high-performance Lithium-sulfur (Li–S) batteries. Recently, cellulose nanocrystals (CNCs) receive extensive attention for advanced energy storage applications owing to their intrinsically exceptional physical/chemical properties and natural abundance. Herein, a highly dispersed cobalt clusters/nanoparticles embedded into CNC derived carbon aerogel composite (CA/Co-2) is for the first time synthesized. Benefiting from the interconnected hierarchical porous structure, homogeneously anchored Co clusters/nanoparticles and N-doped species, the designed CA/Co-2 could enable rapid electron/ion transport, efficient sulfur utilization, effective suppression of the shuttle effect and fast catalytic conversion of polysulfides, thereby contributing to outstanding electrochemical performance. Consequently, CA/Co-2@S cathode delivers high initial discharge capacity (1553.1 mAh g−1 at 0.1C) and superior cycle stability. Moreover, a remarkable rate performance of 681.4 mAh g−1 at 5.0C and exceptional long-term cycling stability with an ultralow capacity decay of 0.028 % per cycle at 5.0C over 1000 cycles could be achieved when coupled with carbon paper interlayer. This work develops a workable strategy for fabricating multifunctional sulfur host derived from the fascinating bio-nanomaterial of CNC, which provides valuable guidance for the future design of high-performance Li–S batteries.