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

Aqueous zinc-based energy storage systems offer high theoretical specific capacity, low cost, intrinsic safety, and environmental compatibility, positioning them as promising candidates for next-generation energy storage and conversion technologies. However, issues such as zinc dendrite growth, hydrogen evolution reaction (HER), and surface passivation hinder their practical deployment. To address these challenges, a hollow nanotubular magnesium silicate (denoted MgSi) interfacial layer was constructed on the zinc metal anode (Zn@MgSi). The unique layer structure and negatively charged surface of MgSi facilitate the desolvation of [Zn(H₂O)₆]²⁺ by stripping water molecules, while temporarily immobilizing Zn²⁺ to suppress random diffusion. The combined effects of the electric field-guided Zn²⁺ distribution and rapid ion transport through the layer structure co-regulate Zn²⁺ flux, leading to uniform, dendrite-free zinc deposition. Consequently, the Zn@MgSi symmetric cell demonstrates a high Zn²⁺ transference number (0.64), extended cycling life exceeding 1600 h at 1 mA cm⁻², and stable operation for 200 h at 5 mA cm⁻². Furthermore, zinc-ion hybrid capacitors employing Zn@MgSi electrodes exhibit excellent cycling stability over 5000 cycles. This work highlights the efficacy of artificial interfacial layers in stabilizing zinc metal anodes and provides valuable insights into the development of advanced aqueous zinc-ion energy storage systems.