Constructing Autoregulative Electric Double Layer Through Dielectric Effect Toward Fast Charging Zinc Metal Anode

Abstract The inhomogeneous dendrite growth and parasitic side reactions of Zn anodes as well as its sluggish solvation/de‐solvation kinetics severely hinder the practicalization of fast charging Zn‐ion batteries. Regulating electric double layer (EDL) structure is an effective strategy to address these issues. Herein, a perovskite dielectric ZnTiO 3 (ZTO) layer is designed on Zn anode to construct the autoregulative EDL for achieving fast charging capability. The ZTO layer can spontaneously generate the surface charge with external voltage to regulate the EDL structure, which results in an increased/decreased EDL capacitance under Zn plating/stripping potential respectively, leading to promoted Zn 2+ solvation/de‐solvation for rapid reaction kinetics. Meanwhile, the H 2 O‐insufficient environment created by self‐regulated EDL and uniform electric field can prevent side reaction and dendrite growth during deposition process. Attributed to its EDL feature, ZTO@Zn exhibits an excellent cycle stability over 2850 h at 1 mA cm −2 in symmetrical cells. Even at high current density of 50 mA cm −2 , it still exhibits a stable cycle for 230 h. Additionally, the as assembled ZTO@Zn//AC supercapacitor demonstrates ultralong lifetime of 140 000 cycles at 5 A g −1 . This work provides an effective EDL regulation strategy to realize fast charging capability of metal anode for its practical application.