Micro-sized silicon-carbon composites composed of carbon-coated sub-10 nm Si primary particles as high-performance anode materials for lithium-ion batteries

We report the synthesis of micro-sized silicon-carbon (Si-C) composites, which simultaneously possess primary sub-10 nm Si particles and secondary micro-sized aggregation coated with carbon. Because of this unique structure, the as-synthesized Si-C composite anode can deliver excellent cycling stability with a high reversible specific capacity (∼1600 mA h g^-1) within 150 cycles at 400 mA g^-1. Moreover, a high volumetric capacity of ∼1088 mA h cm^-3 was demonstrated by using this composite cathode, which is 5 times higher than that of commercially available nano-silicon based anodes.