Optimized Nitrogen Sites in Yolk‐Shell ZnNCN/Nitrogen‐Doped Carbon Composite Interfacial Layer for Dendrite‐Free and Highly Reversible Zn Anodes

Abstract Achieving stable zinc plating/stripping in zinc anodes is crucial for the development of high‐performance aqueous Zn‐ion batteries, but dendrite growth and side reactions severely limit their lifespan. Herein, a hydrophobic and zincophilic ZnNCN/nitrogen‐doped carbon composite (ZNC800) with a hollow yolk‐shell structure is designed for interfacial engineering. The ZNC800 interfacial layer incorporates optimized nitrogen sites with abundant Zn─N bonds, pyridinic nitrogen species, and π ‐conjugated NCN groups, which synergistically enhance Zn adsorption energy, lower ion diffusion barriers, and promote efficient Zn ²⁺ desolvation. Simultaneously, the hydrophobic interfacial layer helps reduce side reactions such as hydrogen evolution and corrosion, while the yolk‐shell architecture buffers volume changes. Consequently, the ZNC800‐Zn electrode exhibits highly reversible Zn plating/stripping with extended cycling lifespan exceeding 2100 h at 1 mA cm ⁻² and 1 mAh cm ⁻² and maintains stability under extremely deep discharge conditions (DOD ≈ 95.7% over 228 h). It also delivers up to 2400 cycles with an average Coulombic efficiency of 99.65%, and the ZNC800‐Zn||NaV ₃ O ₈ ·1.5H ₂ O full cell exhibits a capacity retention of 76.93% after 7850 cycles at 10 A g ⁻¹ . These findings underscore the promising potential of nitrogen site optimization and yolk‐shell structure in interfacial engineering for dendrite‐free and highly reversible metal electrodes in aqueous systems.