Rechargeable aqueous zinc-ion batteries (AZIBs) are close complements to lithium-ion batteries for next-generation grid-scale applications owing to their high specific capacity, low cost, and intrinsic safety. Nevertheless, the viable cathode materials (especially manganese oxides) of AZIBs suffer from poor conductivity and inferior structural stability upon cycling, thereby impeding their practical applications. Herein, a facile synthetic strategy of beadlike manganese oxide coated with carbon nanofibers (MnO x -CNFs) based on electrospinning is reported, which can effectively improve the electron/ion diffusion kinetics and provide robust structural stability. These benefits of MnO x -CNFs are evident in the electrochemical performance metrics, with a long cycling durability (i.e., a capacity retention of 90.6% after 2000 cycles and 71% after 5000 cycles) and an excellent rate capability. Furthermore, the simultaneous insertion of H + /Zn 2+ and the Mn redox process at the surface and in the bulk of MnO x -CNFs are clarified in detail. Our present study not only provides a simple avenue for synthesizing high-performance Mn-based cathode materials but also offers unique knowledge on understanding the corresponding electrochemical reaction mechanism for AZIBs.

No abstract

Aqueous zinc‐ion batteries (AZIBs) have aroused continuously increasing attention for grid‐scale energy storage applications. However, the progress of AZIBs is largely plagued by their sluggish reaction kinetics and poor structural reversibility, which are closely related to the desolvation process of hydrated Zn2+. Herein, a strategy of local coordination engineering is proposed to modulate both surface and bulk structure of a conventional α‐MnO2 cathode to overcome these issues. Theoretical simulations and experimental characterizations reveal that the surface F coordinations effectively adjust the absorption strength toward H2O and Zn, which facilitates the desolvation of hydrated Zn2+ and thus improves the interfacial ion diffusion rate and reaction kinetics. Meanwhile, the structural integrity is largely enhanced with suppressed irreversible phase evolution over cycling benefiting from the presence of robust MnF bonds in the bulk lattice. As a consequence, the achieved cathode exhibits almost no capacity degradation after 400 cycles at a low current density of 0.5 A g‐1 and long‐term durability over 3500 cycles at a high current density of 5 A g‐1. The proposed modulation strategy provides new opportunities for designing long‐cycling and high‐energy cathodes for AZIBs and beyond.

No abstract