Heterostructured Bi 2 O 3 @rGO Anode for Electrochemical Sodium Storage.

Bismuth oxide (Bi 2 O 3 ) 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 2 O 3 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 2 O 3 @rGO heterostructure. It exhibits high reversibility and stability for electrochemical sodium storage by delivering a reversible capacity of 161 mAh g -1 after 100 cycles at 50 mA g -1 , which completely outperforms Bi 2 O 3 (43 mAh g -1 ). 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 2 O 3 nanoparticles and providing conductive pathways to fasten electron transport.