Silicon nanowires coated with copper layer as anode materials for lithium-ion batteries

Silicon nanowires (Si NWs) with copper-coating as high capacity and improved cycle-life anode for lithium-ion batteries have been successfully prepared by chemical vapor deposition and magnetron sputtering methods. The morphology, structure, composition as well as the electrochemical performance of copper-coated Si NWs is characterized in detail. The results indicate that the copper-coated Si NWs electrodes show an initial coulombic efficiency of 90.3% when cycling between 0.02 V and 2.0 V (versus Li/Li⁺) at a current density of 210 mA g⁻¹. The copper-coated Si NWs electrodes exhibit a capacity as high as 2700 mAh g⁻¹ at the first cycle. They also show a good capacity retention and excellent rate capability compared with pristine and carbon-coated Si NWs.