Realizing dendrite-free Zn anode using an efficient sulfone-based electrolyte additive for high-performance aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have emerged as a promising next-generation energy storage solution due to their high energy density, abundant resources, low cost, and high safety. However, unstable zinc anode caused by side reactions and dendritic growth always severely worsens the long-term operation of AZIBs. Herein, a novel 3-cyclobutene sulfone (CS) additive was employed in the aqueous electrolyte to achieve a highly reversible Zn anode. The CS additive can offer strong electronegativity and high binding energy for the coordination with Zn 2+ , which enables its entry into the solvent sheath structure of Zn 2+ and eliminates the free H 2 O molecules from the solvated {Zn 2+ -SO 4 2− -(H 2 O) 5 }. Thus, the occurrence of side reactions and dendritic growth can be effectively inhibited. Accordingly, the Zn anode achieves long cycle-life (1400 h at 1 mA cm −2 , 1 mAh cm −2 , and 400 h at 5 mA cm −2 , 5 mAh cm −2 ) and high average coulombic efficiency (99.5% over 500 cycles at 10 mA cm −2 , 1 mAh cm −2 ). Besides, the assembled Zn||NH 4 V 4 O 10 full cell suggests enhanced cycling reversibility (123.8 mAh g −1 over 500 cycles at 2 A g −1 , 84.9 mAh g −1 over 800 cycles at 5 A g −1 ) and improved rate capability (139.1 mAh g −1 at 5 A g −1 ). This work may exhibit the creative design and deep understanding of sulfone-based electrolyte additives for the achievement of high-performance AZIBs.