A long-term stable zinc metal anode enabled by a mannitol additive

Abstract

Despite the promising potential of zinc-ion batteries (ZIBs) for large-scale energy storage applications, their electrochemical performance is still hindered by zinc dendrites and side reactions. To address these challenges, the optimization of electrolyte composition emerges as a practical and straightforward approach to enhance the coulombic efficiency (CE) and Zn plating/stripping reversibility of ZIBs. Here, mannitol stands out due to its abundance of polar groups and cost-effectiveness, and an electrolyte mixture consisting of 0.02 M mannitol and 2 M ZnSO₄ is demonstrated, resulting in an impressive improvement in Zn reversibility compared to the pure ZnSO₄ electrolyte. Density functional theory (DFT) calculations and spectroscopic analysis shed light on mannitol's capability to reconstruct the solvation structure of Zn²⁺ and replace free water molecules. The inhibited dendrite growth on the zinc metal anode is further confirmed through in situ characterization. This work paves the way for the development of long-lifespan ZIBs.