The gas-phase self-assembly of Sn-SnO2@hollow carbon nanospheres (HCNSs) synthesized by floating catalytic chemical vapor deposition, as a new, facile, and scalable method, was performed, and the resultant nanospheres displayed an enhanced lithium storage performance. Freshly synthesized Sn nanoparticles [≈25 nm in equivalent mobility diameter (EMD)] were incorporated quantitatively with dimethyl sulfide (DMS)-ethanol (EtOH) droplets (≈45 nm in EMD) in the form of Sn/DMS-EtOH hybrid droplets (≈42 nm in EMD). The hybrid droplets were employed to perform catalytic chemical vapor synthesis in a heated tubular reactor. It was observed that Sn-SnO2 particles with sizes between 3–6 nm were dispersed in the HCNSs (≈25 nm in lateral dimension), and no bulky aggregates were visible. Its reversible capacity even increased up to ≈870 mA h g−1 after 50 cycles, which is much higher than the conventional theoretical capacity of SnO2 (782 mA h g−1).