Manipulating the Electronic Structure of Bismuth Oxide by Selenium Incorporation for Efficient and Reversible Zinc-Ion Storage

Bismuth oxide, with its large internal spaces and adjustable structures, is a promising electrode material for zinc-ion batteries (ZIBs). However, its application is limited by poor reversibility and rapid capacity fading in neutral zinc-ion electrolytes. Here, we introduce selenium into bismuth oxide using chemical vapor deposition, precisely controlling the Se content by adjusting the gas flow rate. The Se-doped materials, particularly CC/Bi 2 O 2.5 Se 0.5 and CC/Bi 2 O 2 Se, exhibit significant improvements in specific capacity and cycling stability. CC/Bi 2 O 2 Se achieves a maximum specific capacity of 312.5 mAh g −1 at 0.1 A g −1 , with a retention rate of 74.6% after 4000 cycles at 2 A g −1 . The enhanced performance is attributed to the narrowed band gap and improved electrical conductivity resulting from Se doping, which facilitates electron and ion transport. More importantly, Se incorporation mitigates the formation of detrimental by-products, ensuring more reversible and efficient Zn-ion storage. It also stabilizes the Bi 3+ ↔Bi° conversion pathway observed during cycling, providing a metal-centered rationale for the improved reversibility. This work highlights the importance of electronic structure regulation in optimizing the performance of metal oxide electrodes and provides valuable insights for the rational design of high-performance energy storage materials.