High-capacity nano-Si@SiOx@C anode composites for lithium-ion batteries with good cyclic stability

To suppress the volume change of silicon and enhance the conductivity of the electrodes, nano-Si@SiO x @C composites with different carbon content are synthesized, in which nano-Si is embedded in SiO x matrix and coated by pyrolyzed C. Among the as-prepared composites, nano-Si@SiO x @22.45 wt%C exhibits the best comprehensive electrochemical performance, which delivers a first reversible capacity of 1184 mAh g −1 with capacity retention of 93% after 150 cycles at 100 mA g −1 . Moreover, it also shows good rate capability. The excellent electrochemical performance is attributed to the special structure and rational composition of the composite, in which the combination of a modest amount of coating carbon and SiO x matrix not only effectively mitigates the volume effect of nano-Si particles but also guarantees a high reversible capacity.