Adjusting Zinc Ion De-Solvation Kinetics via Rich Electron-donating Artificial SEI towards High Columbic Efficiency and Stable Zn Metal Anode

A quickly kinetics for de-solvation of hydrate zinc ions benefits from the interaction between electron-donating group and water sheath of hydrated ions. Rich-cyano SEI (rc-SEI) for Zn anode was prepared by coating polyacrylonitrile (PAN) on zinc foil, which realizes low de-solvation activation energy (Ea) of hydrated ions (41.9 kJ mol -1 for rc-SEI@Zn and 63.7 kJ mol -1 for bare Zn). • Cyano as electron-donating group can interact with sheath of hydrated ions. • Rich-cyano SEI (rc-SEI) reduces de-solvation activation energy of hydrated ions. • Rc-SEI contributes to dendrite-free deposition and high CE of zinc anode. • Rc-SEI improves the cycling performance of a full battery with lean zinc anodes. Aqueous zinc ion batteries (AZIBs) subject to severe sluggish electrodeposition process due to burdensome de-solvation of hydrate zinc ion (Zn(H 2 O) 6 2+ →Zn 2+ ) which leads to high overpotential, low utilization of zinc and high interface impedance. Here, artificial solid electrolyte interphase (SEI) with rich electron-donating functional group (cyano group) is proposed for zinc anode to achieve favorable de-solvation process and deliver stable rechargeable AZIBs. The rich-cyano SEI (rc-SEI) can improve the de-solvation kinetics through formation interaction force between cyano group and water sheath of hydrated ions. The de-solvation activation energy (E a ) of hydrated ions for rc-SEI@Zn is only 41.9 kJ mol -1 , whereas bare Zn shows much higher activation energy for de-solvation (63.7 kJ mol -1 ). The rc-SEI@Zn electrode realizes an enhanced CE of over 99.65 % within 550 cycles in Zn||Cu battery, a low polarization of less than 50mV and ultra-long cycle life of over 1000h in Zn||Zn battery. Moreover, Zn||MnO 2 full cell with rc-SEI@Zn anode shows 78.9% capacity retention after 690 cycles at 2C (218.2 mAh g -1 at 1 st cycle and 172.1 mAh g -1 at 690 th cycle). This work opens up new frontiers to deliver a favorable electrodeposition process for zinc anode.