Layered Topological Insulator MnBi₂Te₄ as a Cathode for a High Rate Performance Aqueous Zinc-Ion Battery

Recently, the topological insulator MnBi₂Te₄ has aroused great attention owing to its exotic quantum phenomena and intriguing device applications, but the superior performances of MnBi₂Te₄ have not been researched in the field of electrochemistry. By theoretical calculations, it is found that MnBi₂Te₄ exhibits excellent Zn²⁺ storage and transport properties. Therefore, it is speculated that MnBi₂Te₄ has excellent electrochemical performance in zinc-ion batteries (ZIBs). In this research, MnBi₂Te₄ as a pioneer has been explored in ZIBs, showing surprising electrochemical properties. The MnBi₂Te₄ electrode displays a high average discharge specific capacity (264.8 mA h g^-1 at 0.40 A g^-1), a competitive cycle life (88.6% of initial capacity after 400 cycles at 4.00 A g^-1), and an excellent rate performance (average capacity retention rate of 95.1% from 0.40 to 8.00 A g^-1) owing to the fast ion transport of the conductive topological surface state and dissipationless channel of the edge state. Surprisingly, the quasi-solid-state (QSS) MnBi₂Te₄/Zn battery delivers excellent Zn²⁺ storage capability and possesses a capacity retention of 79.9% after 1000 cycles at 4.00 A g^-1. In addition, the QSS MnBi₂Te₄/Zn battery can exhibit excellent performance and the GCD curves maintain stability without distortion deformation even at temperatures of 0 and 75 °C.