Nano-sized SiOx/C composite anode for lithium ion batteries

Abstract Nano-sized SiO x /C composite with core–shell structure is prepared by a modified Stober method. After heat-treatment, the O/Si ratio in SiO x /C composite is near 1 and the core of SiO x presents a structure composing of amorphous Si clusters and ordered SiO 2 domains. SiO x /C composite anode shows high specific capacity (ca. 800 mAh g −1 ), excellent cycling stability, good rate-capability but low initial coulombic efficiency. Li 2 O and Li 4 SiO 4 may generate in the initial lithiation process, which, combining with the carbon shell, can buffer the volume change caused by the alloying of Si with Li, and thereby improving the cycling stability of electrode. The nano feature of SiO x /C particle and the electronic conductive nature of carbon coating layer ensure the good rate-capability of SiO x /C electrode.