Tellurium vacancy-rich Bi₂Te₃ as a high-performance cathode material for aqueous zinc ion storage

Layered transition metal tellurides (TMT) show potential for development into high-performance cathode materials for aqueous zinc ion batteries, yet their holistic performance metrics (e.g., specific capacity, rate capability, stability) remain substantially distant from practical utilization. Herein, we employed a straightforward and efficient NaBH4-assisted chemical etching method to generate abundant Te vacancies on the surface of Bi2Te3 (termed H-Bi2Te3). Our experimental and theoretical investigations reveal that these abundant Te vacancies refine the band structure of H-Bi2Te3, enhance its electrical conductivity, and remarkably decrease the diffusion barrier for zinc ions. Moreover, these Te vacancies offer increased storage sites for Zn ions. Consequently, the H-Bi2Te3 material showcased superior performance in zinc-ion storage, exhibiting rapid zinc storage kinetics ( D Zn 2+ of 3.98×10−11 cm2 s−1), a noteworthy specific capacity (325 mAh g−1 at 0.1 A g−1), impressive rate characteristics (217 mAh g−1 at 1 A g−1), and exceptional cyclic stability (retaining a capacity of 70 mAh g−1 after 10000 cycles at 1 A g−1). This work not only presents a novel strategy focused on vacancy defect engineering on TMT-based cathode materials in AZIBs, but also opens up possibilities for exploring broader applications of vacancy-rich TMT materials.