Constructing Bi2Se3/Bi2O3 heterostructure as promising anode for efficient sodium-ion storage.

• The Bi 2 Se 3 /Bi 2 O 3 heterostructure is constructed by a simple hydrothermal reaction and oxidizing process. • The topological insulated feature of Bi 2 Se 3 provides substantial electron transport pathways. • Electrons/ions transportation kinetics are accelerated due to the island-like heterostructure. • Structural degeneration of Bi 2 Se 3 is inhibited. • A capacity of 310 mAh/g is reserved after 100 cycles at 0.1 A/g. The Bi 2 Se 3 / Bi 2 O 3 heterostructure was constructed and explored its sodium storage capability. The results showed that the island-like heterostructure architecture is more conducive for Na ion storage, which accelerates electrons/ions transportation and brings better electrochemical performance than their building blocks. [Display omitted] Sodium-ion batteries (SIBs) have been a promising potential alternative for sustainable electrochemical energy-storage devices. Bismuth-based materials can reserve substantial Na ions through alloying reaction and conversion reaction, leading to superior theoretical capacity. However, the alloying reaction is always accompanied by huge volume change during sodiation/desodiation processes. Herein, a flower-like Bi 2 Se 3 /Bi 2 O 3 heterostructure is designed to address the structural degeneration problem of Bi-based materials. Diverse Bi 2 Se 3 /Bi 2 O 3 heterostructures are produced via a facile hydrothermal reaction and subsequent annealing process, presenting apparently improved rate capability and cycling stability. Such excellent Na ion storage performance attributes to the charge redistribution around heterointerfaces caused by the unmatched band structure of two building blocks. The redistributed charges induce a dissimilar charged space nearby the phase boundaries, which not only enhance the structural integrity via coulombian force but also accelerate the diffusion of Na ions traversing heterointerfaces through electric field force. Meanwhile, the unique surface conducting states of Bi 2 Se 3 can facilitate charge transport effectively. The initial discharge capacity of electrode reached 571 mAh/g at the current density of 0.1 A/g and maintained 310 mAh/g after 100 cycles. This work may provide a new route to enhance the structural stability of the serious volume expansion electrode materials. [ABSTRACT FROM AUTHOR]