Growth of hierarchal porous CoO nanowire arrays on carbon cloth as binder-free anodes for high-performance flexible lithium-ion batteries

Hierarchal three-dimensional (3D) CoO nanowire arrays have been directly grown on flexible carbon cloth substrate via a hydrothermal method, which can be used as a binder-free flexible anode for lithium ion battery (LIBs). These porous CoO nanowire arrays give rise to large surface area and space for efficient buffering of the volume change during electrochemical lithiation. The integrated hierarchal electrodes possess many advantages by directly building 3D nanostructures on conductive substrate, such as short diffusion length, easy strain relaxation and fast electron transport. Thus, the CoO nanowire arrays show an improved lithium-storage performance with high cycling stability and good rate capacity. It exhibits an initial discharge capacity of 1730 mAh g −1 and retains a reversible gravimetric capacity of about 1300 mAh g −1 after 90 cycles at a current density of 100 mA g −1 . Moreover, the integrated CoO nanowires/carbon cloth electrode shows high flexibility and high areal capacity (1.95 mAh cm −2 ), which can be directly used as an anode to build flexible LIBs.