The synergistic effect induced by "Z-bond" between cations and anions achieving a highly reversible zinc anode.

Due to their high energy density, low cost, and environmental friendliness, aqueous zinc-ion batteries are considered a potential alternative to Li-ion batteries. However, dendrite growth and parasitic reactions of water molecules limit their practical applications. Herein, an ionic liquid additive, 1-butyl-3-methylimidazolium Bis(fluorosulfonyl)imide (BMImFSI), is introduced to regulate the electrical double layer (EDL). Both BMIm and FSI can preferentially adsorb on the Zn anode, constructing a water-poor EDL and thus effectively suppressing side reactions. Additionally, under the synergistic effect of the mineralized solid-electrolyte interphase (SEI) formed by the decomposition of FSI and the ion dispersion layer constructed by BMIm on the mineralized SEI, the deposition of zinc ions is effectively dispersed, preventing excessive aggregation of zinc ions and thus dendrite formation. The Zn‖Zn symmetric cells using the BMImFSI/ZnSO electrolyte operate stably for 1060 h and 560 h at 10 mA cm-10 mAh cm and 20 mA cm-20 mAh cm, respectively. The Zn‖Cu asymmetric cell maintains an average Coulombic efficiency of 99.4 % after 1000 cycles. The capacity retention of a full cell using α-MnO as the cathode is significantly improved at 1 A g.