Dual-functional ionic liquids additive enables dendrite-free Zn anode with ultra-long cycle life over one year.

A dual-functional ionic liquid additive, 1-butyl-3-methylimidazolium hydrogen sulfate (BMIHSO 4), is developed to tune the preferential Zn(002) crystallographic texture and simultaneously suppress the hydroxide sulfate accumulation on Zn anode by dynamically manipulating electrolyte pH-surroundings. The effective suppression of Zn dendrite growth enables a Zn symmetrical cell cycling stably to over one year. [Display omitted] Zn anodes suffer from the formation of uncontrolled dendrites aggravated by the uneven electric field and the insulating by-product accumulation in aqueous zinc-ion batteries (AZIBs). Here, an effective strategy implemented by 1-butyl-3-methylimidazolium hydrogen sulfate (BMIHSO 4) additive is proposed to synergistically tune the crystallographic orientation of zinc deposition and suppress the formation of zinc hydroxide sulfate for enhancing the reversibility on Zn anode surface. As a competing cation, BMI+ is proved to preferably adsorb on Zn-electrode compared with H 2 O molecules, which shields the "tip effect" and inhibits the Zn-deposition agglomerations to inducing the horizontal growth along Zn (002) crystallographic texture. Simultaneously, the protonated BMIHSO 4 additives could remove the detrimental OH– in real-time to fundamentally eliminate the accumulation of 6Zn(OH) 2 ·ZnSO 4 ·4H 2 O and Zn 4 SO 4 (OH) 6 ·H 2 O on Zn anode surface. Consequently, Zn anode exhibits an ultra-long cycling stability of one year (8762 h) at 0.2 mA cm−2/0.2 mAh cm−2, 3600 h at 2 mA cm−2/2 mAh cm−2 with a high plating cumulative capacity of 3.6 Ah cm−2, and a high average Coulombic efficiency of 99.6 % throughout 1000 cycles. This work of regulating Zn deposition texture combined with eliminating notorious by-products could offer a desirable way for stabilizing the Zn-anode/electrolyte interface in AZIBs. [ABSTRACT FROM AUTHOR]