Enhanced CuZn Coating on Carbon Fibers Through C─O─Cu Bridging Bond for Homogeneous Zinc Deposition in Zinc‐Iron Flow Batteries

Zinc-based flow batteries (ZFBs) are promising for grid-scale energy storage due to their high energy density, low cost, and safety. However, uneven zinc plating, dendrite formation, and limited areal capacity in Zn anodes remain significant challenges. To address these issues, carbon felt (CF) electrodes are functionalized with oxygen-containing groups to form stable C─O─Cu bridging bonds, which enhance the adhesion of CuZn to CF. This modification promotes uniform deposition of a CuZn alloy layer on the carbon fibers, which increases zinc adsorption and ensures consistent zinc deposition, effectively suppressing dendrite growth. In zinc-iron flow batteries, the CuZn-coated carbon felt (CF-CuZn) electrode achieves stable cycling with an average coulombic efficiency of 99.7% and a high areal capacity of 180 mAh cm^-2. This work introduces a scalable strategy that surpasses conventional methods in improving zinc deposition uniformity and dendrite suppression, offering durable, high-performance zinc anodes for grid-scale energy storage applications.