Zn-Rejuvenated and SEI-Regulated Additive in Zinc Metal Battery via the Iodine Post-Functionalized Zeolitic Imidazolate Framework-90

摘要

Due to the high abundance of their components, low cost, and high safety,zinc-based batteries open up new vistas for large-scale energy storage.However, their stability, lifetime, and reversibility are impaired by passivationand dendrite growth of the Zn anode. Here, this challenge is circumvented byan iodine post-functionalized zeolitic imidazolate framework-90 (ZIF-90-I)additive, in which the polycation absorbed on Zn anode can regulatesolid–electrolyte interphase (SEI) formation in the 1 m Zn(TFSI)2 electrolyteand induce Zn~(2+) uniform deposition. Moreover, the I3?/I? redox canrejuvenate dead Zn and inhibit dendrites. With the ZIF-90-I additive, Znplating/stripping at 99.5% Coulombic efficiency for 120 cycles is obtained inZn‖Ti cells at 20 mA cm~（?2）/1 mAh cm~（?2）. In addition, Zn‖Zn cells show steadycycling for 1200 h at 5 mA cm?2/1 mAh cm~（?2） with stable overpotentials. Theutilization rate of Zn reaches up to 68.6%. In situ optical microscopy revealssmooth, uniform Zn plating, and the Zn-rejuvenated function from the I3?/I?redox couple. The refreshed SEI with the increase of Zn-rich complexes, andnitrides from adsorbed polycations, are uniform and ZnF_2-rich in theZn(TFSI)_2 + ZIF-90-I electrolyte. The full Zn‖air cells in Zn(TFSI)2 + ZIF-90-Ielectrolyte exhibit excellent cycling stability with stable polarization voltage at0.1 mA/0.05 mAh cm~（?2）.