Versatile metallo-supramolecular polymeric interphase for highly reversible zinc metal anodes

Abstract

The instability of the zinc anode stemming from dendrite growth and water-induced parasitic reactions involving hydrogen evolution and spontaneous corrosion has severely hampered the practical application of aqueous zinc metal batteries. The repetitive formation and extinction of zinc dendrites, in particular, can induce dynamic volume fluctuation in zinc anodes, resulting in coulombic inefficiency and a limited cycle lifespan. Herein, we describe a design concept that utilizes dynamic metal-ligand interactions to construct a robust metallo-supramolecular interphase crosslinked by Zn(II)-2,6-bis(1,2,3-triazol-4-yl)pyridines moieties to stabilize the Zn plating/stripping. The designed metallo-supramolecular interphase with a dynamically crosslinked network can not only substantially enhance mechanical resilience to dissipate the plating/stripping-induced stress, but also simultaneously selectively transports Zn2+ cations and facilitates the desolvation process via the dynamic coordinated hopping mechanism. Meanwhile, this chemically inert and hydrophobic metallo-supramolecular interphase can significantly reduce water-induced side reactions by blocking electrolyte permeation. Consequently, such an ultrathin (≈230 nm) interphase layer enables stable Zn plating/stripping for 1200 h at a high current density of 10 mA cm−2 and a capacity of 1 mAh cm−2 in symmetric cells. Furthermore, an improved cycling stability can be attained for Zn//MnO2 full cells.