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)SO4 center dot 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 Na2SO4 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 Na2SO4 (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.

Automated summary

In this research, it was found that Na+ cations can inhibit dendrite growth during Zn plating, while F- anions can effectively inhibit the formation of Zn-4(OH)(6)SO4·nH2O during Zn stripping. NaF exhibits a stronger ability to suppress Zn dendrite formation compared to Na2SO4 during stripping/plating processes. The systematic Zn//Zn cell with 0.1 M NaF additive shows a stable cycling performance of 368 h, significantly longer than Na2SO4 (253 h) and blank sample (171 h). This work provides a novel strategy for alleviating dendrite growth by optimizing the anion of additives. The excellent electrochemical performances of various Zn-based energy storage devices verify the broad commercial prospects of aqueous electrolytes with NaF additive.