Conquering Zn Dendrites via Crystal‐Facet Manipulation and Water‐Repellent Interphase Construction

Abstract Aqueous zinc‐ion batteries (AZIBs) are impeded by hydrogen evolution and uncontrolled dendrite growth on Zn metal anodes. A simple, solution‐based strategy is proposed to simultaneously direct crystallographic deposition and reduce interfacial water activity. Cinnamaldehyde (CA) is employed as a molecular surface modifier to form an artificial solid‐electrolyte interphase (ASEI) via a brief immersion. The aromatic moiety of CA imparts strong hydrophobicity, further suppressing water‐triggered side reactions. At the meantime, CA exhibits facet‐selective adsorption, preferentially passivating Zn (002) and (100) planes and thereby guiding Zn 2+ deposition along the (101) orientation. The (101) facet provides intermediate surface energy and plating/stripping barriers, promoting uniform epitaxial growth, improved corrosion resistance, and reduced polarization. Consequently, CA‐modified Zn symmetric cells sustain >2000 h at 1 mA cm −2 with 1 mAh cm −2 . In Zn‖NVO full cells, a specific capacity exceeding 160 mAh g −1 can be maintained after 1000 cycles at 1 A g −1 . This facet‐directed ASEI engineering offers a practical and scalable route to long‐life, dendrite‐resistant Zn anodes for AZIBs.