Vapor-phase crystallization route to oxidized Cu foils in air as anode materials for lithium-ion batteries

Abstract

This paper describes a facile vapor-phase strategy for the crystallization of copper oxide on Cu foil substrate in air and the further fabrication of integrated Cu_xO–Cu electrodes with Cu_xO readily on the Cu foil current collector, without using conductive carbon and binder. The oxidation behavior of Cu foil in air was identified by XRD, SEM and electrochemical measurements. In the whole temperature range from 200 to 800 °C, Cu₂O is the dominant product of the as-oxidized Cu, and CuO is grown on the surface of the Cu₂O layer. The phase composition and thickness of oxidation products can be controlled by the reaction temperature and time. Both thermodynamic data and crystallography of the as-oxidized Cu products indicate that the Cu/Cu₂O/CuO tri-layered structures can be conveniently fabricated according to the oxidation sequence Cu → Cu₂O → CuO. The integrated Cu_xO–Cu electrodes can show better cycling stability and higher capability than those Cu_xO–C blend electrodes. The present work provides a new avenue for the large-scale configuration of integrated metal oxide materials as anode materials for lithium-ion batteries.