Built-in Electric Field and Te Charge Modulation in 2D Bi₂Te₃@Sb₂Te₃ Heterostructure Enable Ultralong Cycling for Lithium-Air Batteries

To address the slow kinetics of Li₂O₂ formation and the unwanted effects of the by-product Li₂CO₃ in lithium-air batteries (LABs), it is crucial to develop high-efficiency and stable catalytic materials. This study presents the application of coherent Bi₂Te₃@Sb₂Te₃ heterostructures with exposed (001) facets as a catalyst in LABs. Theoretical analysis reveals that the difference in work function between Bi₂Te₃ and Sb₂Te₃ leads to electron rearrangement at the interfaces, forming a built-in electric field. This results in an asymmetric charge distribution of Te atoms, which enhances the adsorption capacity of intermediate products and promotes the growth of discharge products. Furthermore, it boosts charge transfer between the adsorbed molecules and the catalytic heterostructure, increasing the overall electrical conductivity of the adsorption system and facilitating the subsequent reaction process. Additionally, the low lattice mismatch between Bi₂Te₃ and Sb₂Te₃ in the coherent heterojunction enhances the structural stability of the Bi₂Te₃@Sb₂Te₃ heterostructure, ensuring stable cycling for LABs. LABs with a Bi₂Te₃@Sb₂Te₃-based cathode achieve 635 cycles in pure oxygen and 537 cycles in air ambient. To this end, this work provides insights into facilitating the applications of coherent heterojunctions with a built-in potential and charge modulation as a highly stable catalyst for LABs.