An efficient route to Cu2O nanorod array film for high-performance Li-ion batteries

• A metal-induced thermal reduction method was used to prepare Cu2O nanorod array film.
• Copper substrate takes an important part in the conversion of Cu(OH)2 to Cu2O.
• The Cu2O films show excellent electrochemical properties as anode for Li-ion battery.

Fabrication of well-organized one-dimensional nanostructured arrays on conducting substrates as binder free electrodes allows us to synergize and integrate multi-functionalities into lithium ion batteries. In this contribution, we report a metal-induced thermal reduction (MITR) method to prepare free-standing Cu2O nanorod array film with average diameters of 400 ± 100 nm and lengths of several microns on copper substrates by direct thermal reduction of Cu(OH)2 nanorod arrays on copper foils in nitrogen atmosphere at 500 °C. The presence of Cu substrates reduces the Cu(OH)2 to Cu2O and decreases the reduction temperature significantly through changing the reaction Gibbs energy. Compared with some previously-reported methods about thermal reduction, the MITR method is facile, controllable, efficient and low energy consumption. The free-standing Cu2O nanorod array film on Cu substrates as anode can achieve high rate capability (315 mAh g− 1 at 10 C) and good cyclability (358 mAh g− 1 after 200 cycles at 1 C), demonstrating their excellent electrochemical performance in lithium ion batteries, which results from relatively faster electron and ion transport, easier electrolyte diffusion and better accommodation of strains from the repeated conversion reactions based on their one-dimensional nanostructured arrays.