Carbon nanofibril composites with high sulfur loading fabricated from nanocellulose for high-performance lithium-sulfur batteries

Abstract Owing to the low cost, high theoretical specific energy density and environmentally friendly, Lithium-sulfur (Li-S) batteries have become one of the most promising candidates for electrical energy storage systems. However, some technical obstacles of lithium sulfur batteries are still addressed, such as the volume expansion, non-conductivity and shuttle effect of polysulfides. Herein, we have described a simple method for preparing carbon nanofiber aerogel (CNFA) via carbonization of the 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-oxidized cellulose nanofibril (TOCN) aerogel. Special three-dimensional (3D) net-like carbon@sulfur(C@S) composite was then successfully fabricated based on CNFA with high porosity, which dramatically alleviates the volume expansion during charging and discharging process of lithium-sulfur battery, improves the conductivity of polysulfide and suppresses the diffusion and dissolution of polysulfide generated during the charge and discharge process. The results showed that the composite material showed an extremely high reversible capacity of 590 mA h g-1 and had a great loaded performance of 390 mA h g-1 with high load 2.9 mg/cm2 over 200 cycles at 0.5 C. Compared with other biomass carbon materials, we have omitted the complicated high-temperature activation pore-forming process. In addition, the high sulfur loading carbon nanofibril composite aerogel also provides a way for the high-quality needs of electronic products.