Formation of Sn@C yolk-shell nanospheres and core-sheath nanowires for highly reversible lithium storage

As one promising anode material with high theoretical capacity, metallic tin has attracted much research interest in the field of lithium-ion batteries. Here, two types of tin/carbon (Sn@C) core-shell nanostructures with inner buffering voids are fabricated from SnO₂ hollow nanospheres via a facile chemical vapor deposition (CVD) method. The crystallinity and surface topography of SnO₂ hollow nanospheres are found to affect the morphology of resultant Sn@C materials. Sn@C yolk-shell nanospheres and core-sheath nanowires are obtained from the as-prepared SnO₂ and high-temperature annealed SnO₂ nanospheres, respectively. The unique Sn@C nanostructures can mitigate the agglomeration/pulverization of Sn nanoparticles and electrical disconnection from the current collector caused by the large volume change during the lithium alloying/dealloying process. Both Sn@C yolk-shell and core-sheath nanostructures show stable cycling performance up to 500 cycles with specific capacities of ca. 430 and 520 mA h g ^-1, respectively. Tin/carbon core-shell conductive and breathable hollow nanostructures, namely, Sn@C yolk-shell nanospheres and core-sheath nanowires with sufficient buffering voids, are prepared by a controlled chemical vapor deposition (CVD) treatment of SnO₂ hollow spheres with varied crystallinity. Both nanocomposites show effective suppression of the pulverization effect during the charging/discharging process and exhibit much stable cycling performance up to 500 cycles.