Supramolecular Interface Buffer Layer for Stable Zinc Anode

Abstract The aqueous zinc ion batteries (AZIBs) are chronically plagued by the inevitable side‐reaction and uneven Zn planets stack. Through regulating the water activity and Zn 2+ crystal dynamics could effectively relieve those anode/electrolyte interface problems. The (2‐hydroxypropyl)‐β‐cyclodextrin (HBCD), characterized by the excluded‐volume and mitigating zinc‐flux aggregation effect, is chosen as the electrolyte additive to tail the anode/electrolyte interface. In this work, the supermolecule interface buffer layer is conducted to screen active water and modulate Zn crystallography. Capitalized on the intense electron density of exterior cavity, the HBCD molecules are proven to chemically adsorb onto anode, which sterically repulse the active waters and disrupt H‐bonds among waters. Concurrently, the (002)‐preferred texture is achieved through inducing Zn 2+ ions transport and nucleation. The assembled symmetric Zn//Zn batteries show ameliorated lifespan at various current density (350 h for 10 mA cm −2 /10 mAh cm −2 and 100 h for 20 mA cm −2 /20 mAh cm −2 ) and steady operation at 73.26% high Depth of Discharge (DOD). The Zn//NVO batteries deliver 380.4 mAh g −1 high discharge capacity at 1 A g −1 . To prove the feasibility, the full battery with a low N/P ratio (2.16) is assembled, it shows ≈260 mAh g −1 discharge capacity and runs stably during 500 cycles.