| Summary: | Bismuth oxide (Bi<sub>2</sub>O<sub>3</sub>) is an auspicious anode material for sodium-ion batteries owing to its high theoretical capacity and abundant Bi resources. However, the poor electronic conductivity and huge volume expansion of Bi<sub>2</sub>O<sub>3</sub> during cycling lead to the low coulombic efficiency and unstable cycling stability. Aiming to suppress these issues, we use highly conductive reduced graphene oxide (rGO) as a continuous skeleton to fabricate a Bi<sub>2</sub>O<sub>3</sub>@rGO heterostructure. It exhibits high reversibility and stability for electrochemical sodium storage by delivering a reversible capacity of 161 mAh g<sup>−1</sup> after 100 cycles at 50 mA g<sup>−1</sup>, which completely outperforms Bi<sub>2</sub>O<sub>3</sub> (43 mAh g<sup>−1</sup>). In addition, the coulombic efficiency of the heterostructure stabilizes at >90% upon only 3 cycles. The results can be attributed to the dual function of rGO in supporting Bi<sub>2</sub>O<sub>3</sub> nanoparticles and providing conductive pathways to fasten electron transport.
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