Carbon Microspheres/Carboxymethyl Cellulose Composite Coating Optimizes Zinc Deposition Behavior of Aqueous Zinc‐Ion Battery Anodes

To address interfacial challenges of the zinc anode in aqueous zinc‐ion batteries (AZIBs), including dendrite growth and by‐product formation, a carbon microspheres/carboxymethyl cellulose (CMC) composite coating (CCZn) is developed on the zinc foil. The composite coating achieves effective regulation of zinc deposition behavior through the synergistic effect of carbon microspheres and CMC. Specifically, the abundant oxygen‐containing functional groups in the coating can form coordination bonds with the zinc substrate to enhance the mechanical stability of the anode. The CMC molecular chains fix the carbon microspheres through a hydrogen bond network to build a 3D stable framework, enabling rapid ion transport. Meanwhile, the rich carboxylate groups in the coating can promote the desolvation process of Zn(H 2 O) 6 2+ , accelerating the kinetics of the zinc ion deposition process. In addition, the presence of the coating can cover the original surface defects of raw Zn (RZn), thereby uniformizing the electric field distribution on the electrode surface to inhibit dendrite growth. Consequently, the CCZn symmetric cell exhibits a cycle life 18 times longer than the RZn cell at 0.8 and 0.8 mAh cm −2 , highlighting its exceptional cycling durability. This work provides a novel interfacial engineering strategy to address zinc deposition challenges in AZIBs.