One-pot template-free synthesis, formation mechanism, and lithium ions storage property of hollow SnO2 microspheres

In this work, we report a facile one-pot template-free approach to prepare hollow rutile SnO2 microspheres using SnCl4 as the precursor in a condensed H2SO4–EtOH mixed solvent. The formation mechanism of the hollow microspheres was proposed on the basis of characterizations. First, the controlled hydrolysis and condensation of SnCl4 to SnO2 nanocrystals was realized by the formation of water via catalytic dehydration of EtOH in the presence of condensed H2SO4. These SnO2 nanocrystals rapidly aggregated to form microspheres in order to minimize their surface energies. Then, Ostwald ripening mechanism governed the subsequent growth and recrystallization of the nanocrystals to form the hollow structure. The resulting hollow SnO2 microspheres exhibited better cycle performance than the pristine SnO2 nanoparticles when used as anode materials in lithium ion batteries.