N-Doped TiCT Interfacial Layer Enabling Uniform Zn Deposition along (002) Plane for Stable Aqueous Zinc-Ion Battery.

Aqueous zinc-ion batteries hold great potentials for large-scale grid energy storage. However, the electrode corrosion, hydrogen evolution, and dendrite growth of Zn anode often lead to cell failure. Herein, N groups in TiCT (NMXH) are introduced as interfacial layer through hydrothermal treatment of TiCT with urea. The experimental analysis and density functional theory calculation indicate that N groups in TiCT can homogenize electric field distribution, promote adsorption of Zn on N groups, and strength interactions between N groups and Zn atoms on (002) plane. Thereby, the use of NMXH interfacial layer can effectively suppress the side reactions and realize uniform Zn deposition along the (002) plane. As a consequence, the NMXH─Zn//Zn cell exhibits an ultralow nucleation overpotential (1 mA cm, 18.9 mV) and can stably operate for 1400 h at 1 mA cm (1 mAh cm) and 110 h at 40 mA cm (1 mAh cm). A full battery with VO nanowires as cathode displays a discharge capacity of 219 mAh g (1.0 A g), along with a decent rate capability and cyclability. The significant role of N groups reported in this work offers a promising avenue to improve the cycling stability of Zn anodes of aqueous zinc batteries.