Anchoring Unimolecular Metal Chloride as a Sterically Active Site for Conformal Zinc Electrodeposition.

Abstract

Aqueous zinc ion batteries are promising candidates for next-generation energy storage systems. However, the practical application of zinc metal anodes is hindered by the challenge of uncontrollable zinc-dendrite growth. Herein, axial-coordinated manganese single atoms, anchored by N, Cl co-coordinating on self-standing carbon nanofibers, are designed to guide uniform Zn deposition. The MnCl₂N₄ octahedral sites act as effective nucleation centers, significantly reducing the Zn adsorption energy of the carbon matrix, achieving a nucleation overpotential of 17 mV. The strong interaction between Zn and MnCl₂N₄ sites stabilizes the initially adsorbed Zn²⁺ through John-Teller distortions, which in turn promotes subsequent zinc adsorption. In symmetric cells, the Mn-modified carbon nanofiber electrodes exhibit excellent cycling stability with a lifespan of 200 h under a high current density of 20 mA cm^-2. Moreover, a full cell coupling a MnO₂ cathode with a Mn-doped carbon nanofiber anode delivers outstanding cycling performance over 1400 cycles at 1 A g^-1. This work highlights the potential of axially coordinated single-atom metals in regulating zinc deposition, offering a pathway toward durable and high-performance ZIBs.