Superhydrophobic metal-organic framework layers as multifunctional ion-conducting interfaces for ultra-stable Zn anodes.

Aqueous zinc batteries (AZBs) show great promise for cost-effective, high-safety, and large-scale energy storage. Yet, corrosion and dendrite formation at the Zn anode interface undermine its stability, shortening the cycle life. In this work, a fluorosilane-modified metal-organic framework layer (F-MOF) is successfully prepared as a multifunctional ion-conductive interface to stabilize the Zn anode. The designed MOF-based artificial layer provides a uniform pathway for Zn deposition, while its hydrophobic nature prevents negative effects such as hydrogen evolution and corrosion. According to density functional theory (DFT) calculations, the hydration energy of Zn2+ in F-MOF@Zn(002) is reduced while the adsorption energy for Zn2+ is increased. This facilitates the desolvation process on the Zn anode surface, promoting uniform Zn deposition. Consequently, the lifespan of the F-MOF-coated Zn anode extends beyond 2000 h at a current density of 1 mA cm−2 (areal capacity: 0.5 mAh cm−2), significantly outlasting both bare Zn (225 h) and MOF-coated Zn (751 h) anodes. Additionally, the assembled coin cells and pouch-type full cells prove the practical availability of F-MOF@Zn anodes for AZBs. The F-MOF@Zn//MnO 2 full cell maintains a high-capacity retention exceeding 91.9 % even after 1000 cycles. This work highlights the practical application potential of hydrophobic MOF coatings for AZBs. [Display omitted] MOF features well-defined ion transport channels that facilitate Zn2+ diffusion, aiding in partially impeding the formation of Zn dendrites at the MOF@Zn anode. However, H 2 O ingress triggers irreversible HER on Zn electrodes, leading to their corrosion. The F-MOF@Zn anode, grafted with long-chain FAS, not only provides uniform pathways for Zn2+ but also serves as a hydrophobic buffer, separating active Zn2+ from the electrolyte [Zn(H 2 O) 6 ]2+, suppressing HER, and minimizing the accumulation of Zn 4 SO 4 (OH) 6 ·xH 2 O and hydrogen bubbles, thereby enhancing corrosion resistance. [Display omitted] • The FAS on F-MOF@Zn ensures uniform Zn2+ channels, preventing HER and corrosion. • DFT calculations show F-MOF enhances Zn2+ transport by disrupting [Zn(H 2 O) 6 ]2+ solvation. • Bare Zn and MOF@Zn symmetrical pouch batteries expands due to HER, while F-MOF@Zn pouch batteries remains stable. • The pouch cells of F-MOF@Zn lighting a bulb and maintaining high capacity after many cycles. [ABSTRACT FROM AUTHOR]