NaF as a bifunctional additive in aqueous zinc electrolytes improves zinc metal reversibility

The severe dendrite growth on Zn anode during the platting process is still a serious roadblock to the commercialization of rechargeable aqueous Zn-based energy storage devices. Introducing electrolyte additives is a facile and efficient strategy to suppress the formation of dendrites. In this work, we found that Na + cations can inhibit the growth of dendrites via the shielding effect during the Zn platting process, and F − can effectively inhibit the formation of Zn 4 (OH) 6 SO 4 ·nH 2 O during Zn stripping process. Benefiting from the synergetic effects of anion (F − ) and cation (Na + ), NaF delivers a stronger ability to suppress the formation of Zn dendrites than that of Na 2 SO 4 during stripping/platting processes. The systematic Zn//Zn cell with 0.1 M NaF as additive shows a 368 h stable cycling performance, significantly longer than those of Na 2 SO 4 (253 h) and blank sample (171 h). Our work provides a novel strategy to alleviate the growth of dendrite via optimizing the anion of additives. The excellent electrochemical performances of various Zn-based energy storage devices verify that the aqueous electrolyte with NaF additive has broad commercial prospects.