Se-decorated SnO2/rGO composite spheres and their sodium storage performances

SnO₂ is considered a promising anode material for sodium-ion batteries due to its high theoretical capacity and low cost. However, the poor electrical conductivity and dramatic volume variation during charge/discharge cycling is a major limitation in its practical applicability. Here we propose a simple one-pot spray pyrolysis process to construct unique pomegranate-like SnO₂/rGO/Se spheres. The ideal structural configuration of these architectures was effective in alleviating the large volume variation of SnO₂, besides facilitating rapid electron transfer, allowing the devised anode to exhibit superior sodium storage performances in terms of capacity (506.7 mAh/g at 30 mA/g), cycle performance (397 mAh/g after 100 cycles at 50 mA/g) and rate capability (188.9 mAh/g at an ultrahigh current density of 10 A/g). The experimental evidence confirms the practical workability of p-SnO₂/rGO/Se spheres in SIBs.