Development of a magnesium silicate nanotube coating for enhanced zinc-ion transport in dendrite-free zinc anodes

Aqueous zinc-based energy storage systems boast high theoretical specific capacity, low cost, inherent safety, and environmental compatibility, making them highly promising for next-generation energy storage and conversion applications. However, challenges such as dendrite formation, hydrogen evolution reactions (HER), and corrosive passivation on the zinc metal surface impede their commercial viability. To tackle these issues, we have developed hollow nanotubular magnesium silicate interfacial layer on the zinc metal anode (Zn@MgSi). This unique layer structure and the negatively charged surface of MgSi strips H₂O molecules from [Zn(H₂O)₆]²⁺ to facilitate the desolvation process. Zn²⁺ is temporarily immobilized at the MgSi sites to avoid random diffusion. The electric field guides the uniform distribution of Zn²⁺ and the ion channel guarantees rapid transport. Ultimately, the Zn²⁺ flux is co-regulated to achieve dendrite-free deposition. Consequently, the Zn@MgSi symmetric cell exhibits enhanced zinc ion transfer number (0.64), improved performance, and the lifespan exceeding 1600 h at 1 mA cm⁻². It also demonstrates robust cycling stability, operating for 200 h at higher current densities (5 mA cm⁻²). Zinc-ion hybrid capacitors assembled with Zn@MgSi electrodes achieve high cycling stability with over 5000 cycles. This study underscores the effectiveness of the artificial interfacial layer strategy in stabilizing zinc metal anodes, providing fundamental understanding for the development of advanced aqueous zinc-ion hybrid capacitors.