Novel silicon nanowire film on copper foil as high performance anode for lithium-ion batteries

A novel silicon nanowire film anode was successfully prepared by a combination of magnetron sputtering deposition and metal-catalyzed electroless etching technology. Scanning electron microscopy revealed the formation of a Si film composed of nanowires with a diameter of ~70 nm and lengths of ~3.5 μm. As-prepared Si nanowire film is directly grown on current collectors without binders and carbon additives, which provides a good contact and adhesion of them to current collector. Furthermore, the defined spacing of nanoscale Si nanowire allows Si to undergo large volume change during the alloying/dealloying process without loss of its integrity. These structural features of the resulting Si nanowire make it a promising anode for lithium-ion batteries with remarkably improved electrochemical performance compared with the Si film-based electrode prepared without metal-catalyzed electroless etching process.