SiOx and carbon double-layer coated Si nanorods as anode materials for lithium-ion batteries

SiOx and carbon double-layer coated Si nanorods (SNs@SiOx/C) were prepared by acid etching Si–Al alloy microspheres, followed by chemical thermal decomposition vapour deposition (TVD). The SNs@SiOx/C composite with 22.7% carbon delivers a specific capacity of 813.1 mA h g−1 for the first cycle at a current density of 400 mA g−1 with a coulombic efficiency of 68.3%. The SNs@SiOx/C composite also exhibits excellent cycling stability with a reversible capacity of 779 mA h g−1 over 300 cycles corresponding to a high capacity retention of 95.8%. The double-layer structure of native SiOx and carbon effectively controls the volume expansion of the SNs, prevents the exposure of SNs to the electrolyte and also enhances electronic conductivity.