Hierarchical C-doped CuO nanorods on carbon cloth as flexible binder-free anode for lithium storage

CuO nanorods have been directly fabricated on flexible carbon cloth (CC) substrate via a facile two-step strategy of magnetron sputtering Cu followed by thermal oxidation, forming a C-doped CuO nanorods/CuO layer/Cu2O layer/CC hierarchical network composite (CC-CuO). The sputtered Cu layer shows a face-center cubic (FCC) phase with a preferential (111) orientation while the CuO nanorod is a monoclinic structure with various kinds of defects. The XPS and TEM results reveal that C atoms are successfully doped into the CuO nanorods. A novel green photoluminescence emission band around 534 nm has been observed from the CC-CuO sample due to the singly ionized oxygen vacancies. The as-synthesized CC-CuO composite can be directly used as the binder-free flexible anode for lithium-ion battery, delivering a stable-reversible capacity of 2.38 mAh cm−2 (646 mAh g−1) and high stable Coulombic efficiency (>99%) after 150 cycles. The high specific capacity and excellent cycling stability are attributed to the three-dimensional hierarchical structure, the excellent conductivity and flexibility of CC substrate, and the high specific surface area of CuO nanorods with various defects. The facile-synthesized C-doped CuO nanorods exhibit superior performance and potential applications in the flexible LIBs and photo-electronics devices. [Display omitted] •CuO nanorods on C cloth can work as flexible binder-free anode for Li-ion battery.•A novel green photoluminescence emission band is obtained due to oxygen vacancy.•Hierarchical 3D structure and various defects improve electrochemical properties.•The stable-reversible capacity after 150 cycles is 2.38 mAh cm−2 (646 mAh g−1).