Amorphous MOF as smart artificial solid/electrolyte interphase for highly-stable Zn-ion batteries

In this work, amorphous MOF (AZ) was used as the artificial SEI of Zn anode, porous inner structure and anions on the AZ molecule chain help the fast Zn2+ transference and smooth Zn deposition, thus realizing long-life aqueous ZIBs. [Display omitted] •Amorphous MOF (ATMP-Zn, AZ) was synthesized via a simple solvothermal method and used as the artificial SEI for Zn anode in aqueous ZIBs.•Uncoordinated radical sites in AZ play an important role in ion conductivity.•Zn ion re-regulation can be realized through the microporous SEI layer.•Negative charged AZ artificial SEI provide ion selectivity to induce a pure Zn deposition.•Desolvation of [Zn(H2O)6]2+ can be achieved by the porous AZ artificial SEI. Zn anodes in aqueous batteries suffer from severe electrochemical corrosion and dendrite growth which impedes the lifespan of aqueous Zn ion batteries (AZIBs). Protective layers with crystallized coatings have been widely employed to restrain dendrites. However, the high-rate performances of batteries are permanently restricted by sluggish diffusion kinetics of Zn2+ in highly crystallized materials due to the steric hindrance by lattice. Herein, the amorphous metal-organic framework (aMOF) of ATMP-Zr (AZ) with sufficient unsaturated ligands and ion transference sites was employed as smart artificial SEI, which was proved to be the shielding layer to suppress side reactions. The micropores in AZ serve as a sieve to achieve desolvation of [Zn(H2O)6]2+ and contribute to the re-regulation of Zn2+ flux, negative-charged character plays as smart ion selective layers, high Zn affinity and dangling bonds (-PO3H− or -PO32−) help to realize high ion transference. The above advantages work synergistically to achieve dendrite-free Zn deposition. Consequently, the AZ-Zn symmetric cells can operate steadily at a high current density of 10 mA cm−2 with a cumulative plating capacity of 4500 mAh cm−2. The AZ-Zn/MVO full cells deliver prominent electrochemical reversibility. This work provides a unique understanding of designing artificial SEI for long-life-span and high-rate AZIBs.