Molecular Structure Regulation Elicits Steric Hindrance of Ketone Additives with High Adsorbability for Oriented Deposition of Zn Anode

Abstract The uncontrollable dendritic growth and interfacial parasitic reactions severely hinder the large‐scale operation of aqueous zinc‐ion batteries (AZIBs), root in the fundamental kinetics imbalance between the excessively rapid electrochemical reduction rate and retarded bulk mass transfer. To resolve this dilemma, a rationally structure‐designed ketone additive, butane‐2,3‐dione (BD), was screened from a series of counterparts to achieve highly reversible Zn plating/stripping by moderating electroreduction kinetics. Specifically, the BD molecule preferentially adsorbs in the inner Helmholtz plane to repel solvated Zn‐ions via the steric‐hindrance effect. The modulated electroreduction kinetics alters zinc deposition behavior, guiding directional Zn (002) texture. Moreover, the constructed H 2 O‐poor electric double layer mitigates parasitic reactions. Notably, the rebalancing of interfacial consumption rate and ion diffusion rate endows Zn anode with superb reversibility (average 99.7% during 1825 cycles) and great cycling durability (2827 h at 1 mA cm −2 and 1276 h at 5 mA cm −2 ). The outstanding electrochemical performance of Zn anode under harsh conditions (423 h, 50 mA cm −2 and 50 mAh cm −2 , 76% depth of discharge) and assembled full cells coupled with multifarious cathodes (Zn//δ‐MnO 2 and Zn//NaV 3 O 8 ·1.5H 2 O) further highlights the versatility of the steric‐hindrance additive in AZIBs.