Adjusting zinc ion de-solvation kinetics via rich electron-donating artificial SEI towards high columbic efficiency and stable Zn metal anode

Aqueous zinc ion batteries (AZIBs) subject to severe sluggish electrodeposition process due to burdensome de-solvation of hydrate zinc ion (Zn(H₂O)₆²⁺→Zn²⁺) which leads to high overpotential, low utilization of zinc and high interface impedance. Here, an 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 by 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, much lower than that of the bare Zn (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 50 mV and ultra-long cycle life of over 1000 h in Zn||Zn battery. Moreover, Zn||MnO₂ full cell with rc-SEI@Zn anode shows 78.9% capacity retention after 690 cycles at 2C (218.2 mAh g⁻¹ at 1st cycle and 172.1 mAh g⁻¹ at 690th cycle).