Accelerating multiple charge transport in topological insulator Bi₂Se₃ for high-performance cathode in aqueous zinc-ion battery

Topological insulator Bi₂Se₃ with high volume specific capacity have attracted much attention for aqueous zinc-ion battery (AZIB) cathode. However, the interior of the Bi₂Se₃ bulk materials still exhibits semiconductor characteristics with low conductivity, and the large Coulomb repulsion field between the divalent zinc-ion and the material matrix results in unsatisfactory kinetics. It has been effective strategy to regulate the lattice and electronic structure of materials via element doping. Herein, Te doped Bi₂Se₃ (Bi₂Se₃-2Te) nanosheets are synthesized to investigate how the anion doping effect on multiple charge transport enhancement in AZIB. Te doping not only accelerates electron mobility, but also expands the lattice spacing of layered Bi₂Se₃ and enhances Zn-ion transport. Benefited from the above characteristics, Bi₂Se₃-2Te cathode exhibits excellent electrochemical performances, delivering a high capacity of 387.38 mAh g−1 at 0.1 A g−1 and maintain a considerable capacity of 83.4 mAh g−1 after 5000 cycles at 10 A g−1. Moreover, the pouch cell (with loading of 10.69 mg cm−2) can operate stably more than 150 cycles at 0.1 A g−1. This study highlights the effectiveness of anion doping in altering the properties of topological insulators, providing a reference for the improvement of metal chalcogenide cathodes in AZIBs.