Simultaneous Dangling Bond and Zincophilic Site Engineering of SiN<inf>x</inf>Protective Coatings toward Stable Zinc Anodes

Metallic Zn is an appealing anode for aqueous Zn-ion batteries, but it suffers from corrosion and Zn dendrites. In this work, we develop a nonstoichiometric silicon nitride (SiNx) film with specific defect sites, i.e., Si dangling bonds (Si DBs), to modify the surface property and thus to enhance the stability of Zn anodes. The Si DBs, together with zincophilic N sites with strong Zn affinity, are able to uniformly distribute Zn2+ions on the anodes, enabling an even Zn deposition. Meanwhile, the electrochemically inert SiNxfilms can also suppress the side reactions to achieve a high Coulombic efficiency. As a result, the SiNx@Zn symmetrical battery possesses a long lifespan of more than 4600 h at 1 mA cm-2. Our work highlights the importance of defect engineering of protective layers in inhibiting the uncontrollable growth of Zn dendrites for constructing high-performance Zn anodes.