High-performance reversible aqueous zinc-ion battery based on iron-doped alpha-manganese dioxide coated by polypyrrole

The development of zinc-ion storage cathode materials for aqueous zinc-ion batteries (AZIBs) is a necessary step for the construction of large-scale electrochemical energy conversion and storage devices. Iron-doped alpha-manganese dioxide (alpha-MnO2) nanocomposites were achieved in this study via pre-intercalation of Fe3+ during the formation of alpha-MnO2 crystals. A polypyrrole (PPy) granular layer was fabricated on the surface of alpha-MnO2 using acid-catalyzed polymerization of pyrroles. The pre-intercalation of Fe3+ effectively enlarges the lattice spacing of alpha-MnO2 and consequently decreases the hindrance for Zn2+ insertion/extraction in the iron-doped alpha-MnO2 coated by PPy (Fe/alpha-MnO2@PPy) composite. Meanwhile, the PPy buffer layer can ameliorate electron and ion conductivity and prevent dissolution of alpha-MnO2 during the charge/discharge process. This unique structure makes the Fe/alpha-MnO2@PPy composite an efficient zinc-ion storage cathode for AZIBs. The targeted Fe/alpha-MnO2@PPy cathode achieves superior performance with reversible specific capacity (270 mA h g(-1) at 100 mA g(-1)) and exhibits high diffusion coefficient of 10(-10)-10(-14) cm(-2) s(-1). Therefore, a feasible approach is implemented on advanced electrode materials using in AZIBs for practical applications. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

In this study, Fe/alpha-MnO2@PPy composite materials were successfully prepared for efficient zinc-ion storage cathode in AZIBs. The optimized structure not only enhances the reversible specific capacity but also exhibits high diffusion coefficient, showing great potential for practical applications in advanced electrode materials for AZIBs.