Flexible CuO Nanosheets/Reduced-Graphene Oxide Composite Paper: Binder-Free Anode for High-Performance Lithium-Ion Batteries

Flexible free-standing CuO nanosheets (NSs)/reduced graphene oxide (r-GO) hybrid lamellar paper was fabricated through vacuum filtration and hydrothermal reduction processes. A unique three-dimensional nanoporous network was achieved with CuO NSs homogeneously embedded within the r-GO layers. This hybrid lamellar composite paper was examined as a binder-free anode for lithium ion batteries, and demonstrated excellent cyclic retention with the specific capacity of 736.8 mA h g–1 after 50 cycles. This is much higher than 219.1 mA h g–1 of the pristine CuO NSs and 60.2 mA h g–1 of r-GO film at the same current density of 67 mA g–1. The high capacitance and excellent cycling performance were generated from the integrated nanoporous structure compose of CuO NSs spaced r-GO layers, which offered an efficient electrically conducting channels, favored electrolyte penetration, and buffered to the volume variations during the lithiation and delithiation process. These outstanding electrochemical capabilities of CuO NSs/r-GO paper holds great promise for flexible binder-free anode for lithium ion batteries.