High performance carbon nanotube-Si core-shell wires with a rationally structured core for lithium ion battery anodes

Core-shell Si nanowires are very promising anodematerials. Here, we synthesize vertically aligned carbon nanotubes (CNTs) with relatively large diameters and large inter-wire spacing as core wires and demonstrate a CNT-Si core-shell wire composite as a lithium ion battery (LIB) anode. Owing to the rationally engineered core structure, the composite shows good capacity retention and rate performance. The excellent performance is superior to most core-shell nanowires previously reported.