A carrageenan-induced highly stable Zn anode by regulating interface chemistry.

Zinc-ion batteries (ZIBs) are promising on account of the inherent safety, minimal toxicity, cost-effectiveness, and high theoretical capacity. However, the critical issues including the Zn dendrites and side reactions impede their commercial application. Here, we propose green, non-toxic and biological carrageenan (Carr) serving as an electrolyte additive to address the aforementioned issues. Owing to the multifunctional groups, Carr has the capacity to interact with Zn, thereby modulating the solvation configuration of Zn and changing the ion distribution at the electrode-electrolyte interface. Moreover, it can adsorb on the Zn electrode and induce the formation of a solid electrolyte interphase (SEI) consisting of ZnO, ZnS and R-SO species. It contributes to uniform Zn ion diffusion and even Zn deposition with the preferable (002) plane. Consequently, the Zn||Zn cells exhibit a stable cycle performance for 800 h at 5 mA cm and 5 mA h cm. An elevated coulombic efficiency of 99.2% over 1800 cycles is obtained in the Zn||Cu cells using the electrolyte with Carr. Benefitting from the highly stable and reversible Zn anode, the Zn||VO full cell also delivers a high performance in comparison with the bare ZnSO electrolyte, favoring the practical implementation of ZIBs.