2-Piperazinone Enhancing the Performance of Zinc-Ion Battery by Optimizing Solvation Sheath of Zn Ions and Suppressing Zn Dendrites

Although aqueous Zn-ion batteries (ZIBs) hold huge promise for large-scale energy storage applications, their electrochemical performance is still hampered by side reactions and the generation of Zn dendrites. In order to address these challenges, optimization of the electrolyte composition is a practical and straightforward way to improve the Coulombic efficiency of ZIBs and the reversibility of zinc plating/stripping. Here, 2-piperazinone (2-PZ) stands out for its planar structure, abundant polar groups, and cost-effectiveness and demonstrates a hybrid electrolyte consisting of 0.2 g L–1 2-PZ and 1 mol L–1 ZnSO4 that significantly improves the reversibility of zinc compared to a pure ZnSO4 electrolyte. Spectral analysis and computations based on density functional theory revealed the ability of 2-PZ to replace free molecules of water to rebuild the solvation structure of Zn2+. In situ characterization further confirmed that dendrite growth on zinc metal anodes was effectively inhibited. This work facilitates the development of high-efficiency ZIBs with extended cycle life.