Chemically anchored NiOx-carbon composite fibers for Li-ion batteries with long cycle-life and enhanced capacity

N-doped carbon fibers and their composites have drawn much attention because of their wide application in energy storage. In this paper, NiOx nanoparticles are anchored on N-doped carbon fibers by chemical bonds with controlled concentration of NiOx, and the fibers interweave into hierarchical structured networks. It is demonstrated that these NiOx nanoparticles consisted of both NiO and Ni-0 other than a single phase. As binder-free anodes for lithium-ion batteries, the NiOx-C fiber networks obtained at 650 degrees C with 9.2 wt% NiOx could deliver a specific capacity of 676 mA h g(-1) after 200 cycles at a current density of 500 mA g(-1). It is also found that the storage and rate capacities of the networks are dependent on both the content of NiOx and the annealing temperature. The improved lithium-ion storage properties can be ascribed to the intimate connection between NiOx and the highly conductive network of carbon fibers through chemical bonds.