In situ preparation of a binder-free nano-cotton-like CuO–Cu integrated anode on a current collector by laser ablation oxidation for long cycle life Li-ion batteries

Abstract

In this paper, we report a unique approach to directly grow nano-scale cotton-like CuO in situ on a Cu current collector using a nano-second laser to ablate it, forming an excellent integrated electrode. This villous nano-cotton CuO is made of micro-scale cotton-like structures, which consist of a huge number of nano-scale particles around 5 nm in diameter. The CuO–Cu integrated anode prepared in 10 minutes by laser ablation exhibits excellent rate performance, coulombic efficiency and a long cycle life. After 800 cycles at 1.5 A g⁻¹, the coulombic efficiency remains higher than 99% and the retention capacity reaches 393.6 mA h g⁻¹. These, to our knowledge, are the highest achieved among currently available CuO integrated anodes. This unique performance is attributed to the villous cotton-like CuO structure, which effectively resists volume expansion and contraction, increases the adhesion of active materials to the current collector, and enhances the conduction of the anode. Laser ablation is a highly efficient and cost-effective approach to prepare integrated oxide-metal anodes for LIBs with a long cycle life. In addition, Fe_xO_y–Fe, Ni_xO_y–Ni integrated anodes were also prepared for LIBs to verify the wide applicability of this method.