Carbon-encapsulated metal oxide hollow nanoparticles and metal oxide hollow nanoparticles: A general synthesis strategy and its application to lithium-ion batteries

A novel and general strategy for the synthesis of carbon-encapsulated metal oxide hollow nanoparticles (HNPs) and pure metal oxide HNPs was developed from carbon-encapsulated metal nanoparticles by controlled oxidation in the air. The materials were characterized by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction measurements. It was found that the morphologies and compositions of HNPs were easily tailored through adjustment of the oxidation conditions. When used as the anode materials for lithium-ion batteries, carbon-encapsulated α-Fe₂O₃ HNPs exhibit excellent cycling performance and a higher reversible capacity of about 700 mA h g^-1 after the 60th cycle and possess great potential application in lithium-ion batteries.