Tellurium vacancy-rich Bi2Te3 as a high-performance cathode material for aqueous zinc ion storage
Layered transition metal tellurides (TMTs) are promising cathode materials for aqueous zinc ion batteries (AZIBs) due to their graphite-like layered structure and weak van der Waals interactions, which facilitate rapid ion transport. However, their holistic performance—specific capacity, rate capability, and cycling stability—remains insufficient for practical applications. Here, we report a straightforward NaBH4-assisted chemical etching method to introduce abundant Te vacancies on the surface of Bi2Te3 (denoted H-Bi2Te3). Experimental and theoretical analyses reveal that these Te vacancies refine the band structure, enhance electrical conductivity, and significantly reduce the diffusion barrier for Zn2+ ions. Additionally, the vacancies provide increased storage sites for Zn ions. Consequently, H-Bi2Te3 exhibits superior zinc storage performance: a high Zn2+ diffusion coefficient of 3.98×10−11 cm2 s−1, a specific capacity of 325 mAh g−1 at 0.1 A g−1, a rate capability of 217 mAh g−1 at 1 A g−1, and exceptional cycling stability with 70 mAh g−1 retained after 10,000 cycles at 1 A g−1. This work introduces a novel vacancy defect engineering strategy for TMT-based cathodes in AZIBs and expands the potential applications of vacancy-rich TMT materials.