A Near‐Single‐Ion Conducting Protective Layer for Dendrite‐Free Zinc Metal Anodes
Hyeong Gyu Jeon, Sungho Heo, Juhyun Song, Chanhoon Kim
Abstract
Abstract The instability of zinc metal anodes, including dendrite formation and corrosion, limits their application in aqueous zinc‐ion batteries (AZIBs). Here, a near‐single zinc‐ion conducting (NSIC) protective layer that enables dendrite‐free Zn anodes by integrating Zn 2 ⁺‐conducting polymer matrices with counter‐anion trapping agents is presented. Sulfonic acid groups, covalently bonded to polymeric backbones enhance Zn 2 ⁺ ion mobility while counter‐anions are immobilized by amine‐functionalized metal‐organic frameworks embedded within the polymer layer. This synergistic combination enables near single zinc ion transport ( t Zn 2 ⁺ = 0.91). The NSIC layer extends sand's time and promotes uniform Zn deposition along the (002) orientation, preventing dendrite formation. Consequently, full cells with thin Zn@NSIC anodes (14 µm) exhibit stable cycling performance over 5000 cycles at 5 A g⁻¹, with a low negative‐to‐positive areal capacity (NP) ratio of 3.3 and a Zn depth of discharge exceeding 30%. Furthermore, the NSIC layer is also adapted for enlarged Zn anodes (80 cm 2 ) in large‐sized full cells, delivering stable operation with a capacity of ≈300 mAh at 1 A g⁻¹. These results offer valuable insights into ion transport control within protective layers, advancing the development of practical AZIBs with high anode reversibility.