Regulating Zn2+ Deposition via a Carbon-Silica Composite Interfacial Layer toward Dendrite-Free Zinc Anodes

Abstract Aqueous Zn-ion batteries (ZIBs) are attractive candidates for safe and cost-effective energy storage, yet the Zn metal anode is still limited by nonuniform electrodeposition, parasitic interfacial reactions, and corrosion in aqueous electrolytes. Herein, a carbon-mesoporous silica (C−Si) interphase was fabricated from coal gasification slag and applied to the Zn surface to direct Zn2+ transport and stabilize plating/stripping chemistry. In the hybrid coating, the carbon component forms an electronically conductive and mechanically accommodating network, whereas mesoporous SiO2 supplies polar oxygen-containing sites with strong affinity for Zn2+. This dual-function architecture redistributes the local electric field and ion flux, lowers the nucleation barrier, and promotes compact Zn growth instead of dendritic deposition. The coating also separates metallic Zn from the bulk electrolyte, thereby retarding corrosion and hydrogen evolution. Consequently, C−Si/Zn symmetric cells operate stably for 2248 h at 4 mA cm−2, and C−Si/Zn//MnO2 full cells retain 88.6% of their initial capacity after 1000 cycles at 2.0 A g−1. This study links low-value coal gasification slag with high-performance Zn-anode interface design and offers a sustainable route to durable aqueous ZIBs.