Targeted Deflecting Zn2+ Migration Trajectory by Piezomagnetic Effect to Enable Horizontal Zn Deposition

Abstract

The rampant growth of dendrites caused by inhomogeneous Zn2+ ion flux and "tip effect" significantly hinder the development of aquesous Zn-ion batteries. The conventional artificial protective layers (APLs) improve Zn anodes stability predominantly through promoting uniform Zn deposition across the entire surface, but still lack targeted control over the localized Zn2+ migration at the tips, resulting in insufficient suppression of protrusion growth. Herein, we have constructed a cobalt ferrite oxide magnetically functional layer on Zn foil (CFO-Zn), endowing the APLs with the ability to targeted control the migration and deposition behaviors of Zn2+ via the piezomagnetic effect. The stress generated on the CFO layer during the deposition process could induce local magnetic field enhancement, deflecting Zn2+ away from the tips, stopping the protrusions growth and consequently rendering the Zn deposition along the horizontal direction. Meanwhile, the CFO magnetic nanoparticles can accelerate and disperse the Zn2+ flow on the anode surface, resulting in improved ion transport and reduced Zn2+ concentration gradient. Additionally, the Zn2+ motion trajectory under electric/magnetic fields co-induction has been simulated, confirming the deflection ability of the magnetic field on Zn2+ migration. The CFO-Zn anodes achieve highly reversible Zn stripping/plating under a cumulative plated capacity of 4750 mAh cm-2.