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The zinc dendrite growth and the parasitic hydrogen evolution reactions (HER) hinder the commercialization of zinc batteries. To address this, a hydroxyl‐rich Boehmite coating (HR‐BC) strategy is developed that combines excellent electrical insulation and high zinc ion conductivity. The hydrophilic hydroxyl groups facilitate hydrogen bond formation with the hydrated zinc ions, accelerating the de‐solvation process and suppressing the HER. Additionally, the electrically insulative nature of Boehmite prevents the reduction of zinc ions within HR‐BC and results in preferential Zn deposition underneath it, leading to a dendrite‐free “sandwich structure” of HR‐BC//Zn deposition//Zn foil. Symmetric cells using HR‐BC‐Zn electrodes obtain an ultralong and stable cycling lifetime of 1700 h at 5 mA cm−2, along with a high cumulative plating capacity of 4250 mAh cm−2. When paired with a V2O5 cathode, the HR‐BC‐Zn anode demonstrates a high capacitance retention of 90% and an average Coulombic efficiency (CE) of 99.8% after 4000 cycles. Furthermore, when combined with a heteroatoms‐doped carbon (HDC) cathode, the HR–BC–Zn//HDC pouch‐type cell exhibits superior lifetime performance with nearly 100% average CE after 15000 cycles at 3.0 A g−1. This work highlights the effectiveness of hydrophilic and insulative coating strategies in fostering the progression of long‐lasting zinc‐based energy storage systems. [ABSTRACT FROM AUTHOR]

Spinel cobalt oxides (Co 3 O 4 ) have emerged as a promising class of catalysts for the electrochemical nitrate reduction reaction (eNO 3 RR) to ammonia, offering advantages such as low cost, high activity, and selectivity. However, the specific role of crystallographic facets in determining the catalysts' performance remains elusive, impeding the development of efficient catalysts. In this study, we have synthesized various Co 3 O 4 nanostructures with exposed facets of {100}, {111}, {110}, and {112}, aiming to investigate the dependence of the eNO 3 RR activity on the crystallographic facets. Among the catalysts tested, Co 3 O 4 {111} shows the best performance, achieving an ammonia Faradaic efficiency of 99.1 ± 1.8% with a yield rate of 35.2 ± 0.6 mg h -1 cm -2 at -0.6 V vs RHE. Experimental and theoretical results reveal a transformation process in which the active phases evolve from Co 3 O 4 to Co 3 O 4- x with oxygen vacancy (O v ), followed by a Co 3 O 4- x -O v /Co(OH) 2 hybrid, and finally Co(OH) 2 . This process is observed for all facets, but the formation of O v and Co(OH) 2 is the most rapid on the (111) surface. The presence of O v significantly reduces the free energy of the *NH 2 intermediate formation from 1.81 to -0.53 eV, and plentiful active sites on the densely reconstructed Co(OH) 2 make Co 3 O 4 {111} an ideal catalyst for ammonia synthesis via eNO 3 RR. This work provides insights into the understanding of the realistic active components, offers a strategy for developing highly efficient Co-based spinel catalysts for ammonia synthesis through tuning the exposed facets, and helps further advance the design and optimization of catalysts in the field of eNO 3 RR.