Fabrication and characterization of carbon nanofiber@mesoporous carbon core-shell composite for the Li-air battery

In this study, we successfully design and synthesize the mesoporous carbon coated carbon nanofibers (CNF@mesoCs) for the Li-air battery. The composites are fabricated via electrospinning technique and nanocasting strategy. After mesoporous carbon coating process, the composites have retained their original one-dimensional structure as pristine carbon nanofibers. Every nanofiber entangles with each other to form a three-dimensional cross-linked web structure. Because of the mesoporous carbon coating on carbon nanofibers, the surface area increases from 708 m2 g−1 to 2194 m2 g−1. We confirm that the mesoporous carbon coated on carbon nanofibers is well-graphitized by analysis of Raman spectra. The graphitized surface of CNF@mesoCs (4.638 S cm−1) is believed to result in their higher electrical conductivity than that of pristine carbon nanofibers (3.0759 S cm−1). Without employment of any binders and metal foams, the cathode of CNF@mesoCs exhibits high discharge capacity of 4000 mA h g−1, which is much higher than that from pristine carbon nanofibers (2750 mA h g−1). This work demonstrates that the fabricated CNF@mesoCs structures have a great potential to be employed as light-weight and efficient electrode for energy storage and conversion devices.