Natural Microcellulose Fibers as Intercalants of Graphitic Cathodes for High-Performance Lithium–Sulfur Batteries

A free-standing highly porous graphitic scaffold of S was fabricated via intercalating microcellulose fibers into graphene oxide (GO) nanosheets, followed by high-temperature carbonization. The abundant porous architecture formed between graphene nanosheets with microcellulose (Cel@Gra) is capable of accommodating sufficient S and buffering S volumetric changes during redox reactions. Moreover, those unstacked graphitic nanosheets inherited the high surface area of GO, and thus offered numerous transmitting routes of both electrons and ions. Upon incorporation of S by Cel@Gra conductive scaffolds, the as-prepared lithium–sulfur battery (LSB) cathodes delivered much higher capacity and superior rate capability in comparison with its pure graphite counterpart. The superior electrochemical behaviors of S/Cel@Gra can be ascribed to the strong adsorption of Cel@Gra toward polysulfides and the enhanced reactive kinetics during charge/discharge. This work provides a sustainable, up-scalable, and cost-effective microcellulose in designing and fabricating high-performance LSB cathodes.