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

Abstract

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.