Multifunctional Hyphae Carbon Powering Lithium–Sulfur Batteries

Abstract Biotechnology can bring new breakthroughs on design and fabrication of energy materials and devices. In this work, a novel and facile biological self‐assembly technology to fabricate multifunctional Rhizopus hyphae carbon fiber (RHCF) and its derivatives on a large scale for electrochemical energy storage is proposed. Crosslinked hollow carbon fibers are successfully prepared by conversion of Rhizopus hyphae, and macroscopic production of centimeter‐level carbon balls consisting of hollow RHCFs is further realized. Moreover, the self‐assembled RHCF balls show strong adsorption characteristics on metal ions and can be converted into a series of derivatives such as RHCF/metal oxides. Notably, the designed RHCF derivatives are demonstrated with powerful multifunctionability as cathode, anode, and separator for lithium–sulfur batteries (LSBs). The RHCF can act as the host material to combine with metal oxide (CoO) and S, Li metal, and a polypropylene (PP) separator to form a new RHCF/CoO‐S cathode, an RHCF/Li anode, and an RHCF/PP separator, respectively. Consequently, the optimized LSB full cell presents excellent cycling performance and superior high‐rate capacity (881.3 mA h g^–1 at 1 C). This work provides a new method for large‐scale preparation of hollow carbon fibers and derivatives for advanced energy storage and conversion.