Effect of oxide layer thickness to nano–Si anode for Li-ion batteries

Oxide thickness controlled amorphous SiO2/nano-Si core–shell structure anode for Li ion batteries was easily prepared by etching with NaOH solution using commercial nano-Si with a native oxide. Based on X-ray diffraction patterns and analysis of high resolution transmission microscope images, the electrode which consists of amorphous SiO2/amorphous Si/core crystalline Si after the first cycle showed a self-limiting reaction behavior. Due to this unique dual core–shell structure for a short diffusion path, a high reversible capacity of about 1800 mAh g−1 over 50 cycles and excellent rate capability could be achieved.