Rod-shaped bismuth oxyiodide as a novel anode material for sodium-ion batteries †

Abstract

Herein, the rod-like bismuth iodide oxide (Bi5O7I) is reported as a negative electrode material for sodium-ion batteries, and its sodium storage performance and mechanism are systematically investigated. The Bi5O7I electrode exhibits high-rate performance (220.5 mA h g-1 at 10 A g-1) and an ultra-long cycle life (292.6 mA h g-1 at 10 A g-1 over 3000 cycles). In situ XRD results reveal that the sodium storage mechanism of the Bi5O7I electrode involves the coupling of conversion and alloying reactions.