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

Abstract

N-doped carbon fibers and their composites have drawn much attention because of their wide application in energy storage. In this paper, NiO_x nanoparticles are anchored on N-doped carbon fibers by chemical bonds with controlled concentration of NiO_x, and the fibers interweave into hierarchical structured networks. It is demonstrated that these NiO_x nanoparticles consisted of both NiO and Ni⁰ other than a single phase. As binder-free anodes for lithium-ion batteries, the NiO_x–C fiber networks obtained at 650 °C with 9.2 wt% NiO_x 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 NiO_x and the annealing temperature. The improved lithium-ion storage properties can be ascribed to the intimate connection between NiO_x and the highly conductive network of carbon fibers through chemical bonds.