In-situ interfacial layer with ultrafine structure enabling zinc metal anodes at high areal capacity

The ramped-up dendritic deposits, hydrogen evolution reaction, and corrosion of the zinc anode at high current density and high areal capacity constitute enormous obstacles to commercializing of aqueous zinc ion batteries (ZIBs). Here, a facile impregnation treatment is reported for the in-situ controllable synthesis of a protective layer composed of ultrafine metallic tin particles on the zinc foil for the first time. Compared with the protection layer with large particles, the surface with ultrafine particles demonstrates an enhanced homogeneous electric field and more active sites to achieve accelerated transport kinetics of zinc ions. Additionally, the nucleation energy barrier is effectively reduced due to the higher surface energy of the ultrafine particles to guarantee the stability of deep electrodeposition at high areal capacity. Therefore, the electrode delivers a durable and steady stripping/plating behaviour over 2000 h at 1 mA cm−2 (1 mAh cm−2) with an extremely reduced voltage hysteresis (≈16 mV). At a high areal capacity of 10 mAh cm−2, it stably cycles for over 300 h with a high depth of discharge (87.8 %). The feasibility of its practical implementation has been validated in coin cells and flexible pouch cells. This work sheds new light on improving the electrochemical deposition behaviour of ZIBs for deep plating/stripping under high current densities, serving as a reference for the design of nanoscale protective layers for ZIBs or other metal batteries.