CoO–carbon nanofiber networks prepared by electrospinning as binder-free anode materials for lithium-ion batteries with enhanced properties

Abstract

CoO_x–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 CoO_x–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.