A Vacancy-Rich Core–Shell Artificial Solid Electrolyte Interphase Design to Manage Anode Chemistry for Aqueous Zinc Batteries

Aqueous zinc-based battery technologies have attracted increasing interest toward safe and sustainable energy storage. Nonetheless, Zn metal anodes face huge challenges in aqueous systems such as serious dendrite growth, corrosion, hydrogen gas evolution, and self-discharge by redox-active species shuttle like polyiodide. Defective TiO_2-<i>x</i> nanoparticles have been proven effective to address the anode interfacial issues, while the structural tunability of TiO_2-<i>x</i> materials with facile fabrication remains to be further explored for advancing Zn chemistry. Herein, we report an effective artificial solid electrolyte interphase (a-SEI) strategy using a core-shell defective TiO_2-<i>x</i>-based nanocomposite for improving Zn anodes. This mesoporous a-SEI endows sufficient active sites, improved electrolyte wettability, and robust interface. More importantly, the defective a-SEI can remarkably improve the zinc affinity that guides its plating and lower the HER reactivity, as evidenced by <i>ex-situ</i> and <i>in situ</i> measurements. Consequently, the defective a-SEI-modified Zn anodes achieve a much more stabilized cycling performance in both symmetric cells and Zn-I₂ full cells. Briefly, this work offers a feasible a-SEI solution and broadens the structure scope of TiO_2-<i>x</i> materials for advancing Zn chemistry.