CoO-carbon Nanofiber Networks Prepared by Electrospinning As Binder-free Anode Materials for Lithium-ion Batteries with Enhanced Properties

CoOx-carbon nanofiber networks were prepared from cobalt(ii) acetate and polyacrylonitrile by an electrospinning method followed by thermal treatment. The XPS results demonstrated that the cobalt compound in CoOx-carbon obtained at 650 °C was CoO rather than Co or Co3O4. The CoO nanoparticles with diameters of about 8 nm were homogeneously distributed in the matrix of the nanofibers with diameters of 200 nm. As binder-free anodes for lithium-ion batteries, the discharge capacities of such CoO-carbon (CoO-C) composite nanofiber networks increased with the pyrolysis and annealing temperature, and the highest value was 633 mA h g(-1) after 52 cycles at a current density of 0.1 A g(-1) when the CoO-C was obtained at 650 °C. In addition, the rate capacities of the CoO-C obtained at 650 °C were found to be higher than that of the sample annealed at a lower temperature and pure carbon nanofiber networks annealed at 650 °C. The improved properties of CoO-C nanofiber networks were ascribed to nanofibers as the framework to keep the structural stability, and favorable mass and charge transport. The present study may provide a new strategy for the synthesis of binder-free anodes for lithium-ion batteries with excellent properties.