Reinforcing the symmetry of stripping/plating behavior via in situ interface construction for long-lasting zinc metal batteries

Abstract

Zn metal batteries (ZBs) are considered promising candidates for next-generation energy storage systems. The cyclic reversibility of ZBs is strictly associated with the interfacial evolution of the Zn anode during the initial stripping. In this contribution, the asymmetry of the stripping/plating behavior is identified as the cause of short circuits and failure of ZBs due to the uncontrollable growth of dendritic Zn. Accordingly, an electrolyte containing N,N′-dimethylpropyleneurea (DU) is designed to regulate the initial stripping behavior for enhancing the cyclic reversibility of the Zn anode. Specifically, DU absorbs on the Zn surface to concentrate perchlorate anions (ClO₄⁻), constructing an initial buffer solid–electrolyte interphase to reduce the stripping energy barrier and regulate the stripping kinetics. With DU, a water-poor solvated structure, Zn[DU]₂[ClO₄]₂[H₂O]₂, further enhances the symmetry of the stripping/plating behavior of the Zn anode. On the above basis, the Zn anode enables reversible cycling for over 6000 hours, and the NH₄V₄O₁₀‖Zn full cell exhibits cycling stability over 5000 cycles with a capacity retention of 85.3%. Even at a low N/P ratio of 3, the NH₄V₄O₁₀‖Zn cell retains 91.54% of its original capacity after 300 cycles. This study provides crucial insight into regulating the stripping/plating symmetry of Zn anodes via electrolyte chemistry, fostering applications of ZB energy storage systems.