Gold-incorporated porous hollow carbon nanofiber for reversible magnesium-metal batteries

•The unique feature of Au@PCNF was achieved using the dual-nozzle electrospinning technique.•The core–shell structure of Au@PCNF contributed to reducing the nucleation overpotentials for Mg plating.•The Au@PCNF enables guiding the even deposition of Mg metal in the substrate. Rechargeable magnesium-metal batteries have received ever-increasing attention as potential alternatives to current Li-ion batteries. Although the most relevant studies have mainly focused on exploring compatible electrolyte and cathode materials, relatively less attention has been paid to the development of an efficient anode host. Herein, we propose a unique anode host with a porous hollow carbon nanofiber structure and gold nanoparticles incorporated in the interior (Au@PCNF). Using the dual-nozzle electrospinning technique, a porous web body was configured with the hierarchical network of hollow carbon nanofibers, with the interior of each string specially designed to embed Au nanoparticles. We demonstrated that Au nanoparticles can act as magnesiophilic sites for Mg plating; therefore, we decorated the magnesiophilic seeds inside the hollow nanofibers to efficiently attract newly deposited Mg metal. The unique feature of Au@PCNF not only reduced the nucleation overpotentials for Mg plating but also guided the even deposition of Mg metal on the substrate. As a result, Au@PCNF exhibited stable and long-term cycle performance with enhanced adhesion property for the newly deposited Mg metal compared with other controls. This novel structural design is promising for the development of efficient anode hosts for magnesium-metal batteries, which will help open an avenue for the practical application of multivalent-ion batteries.