Zwitterion as electrical double layer regulator to in-situ formation of fluorinated interphase towards stable zinc anode

The issues of serious corrosion and dendrite growth in electrode surface hinder the commercialization of aqueous zinc batteries. A stable solid electrolyte interphase (SEI) on electrode surface is critical to improve electrochemical performance of Zn anode. Here, a novel zwitterion additive as an electrical double layer (EDL) regulator with SEI-forming capability is developed. The zwitterion exhibits preferential adsorption with Zn anode to construct a fast Zn2+ migration channel. More importantly, a ZnF2 SEI layer can be in-situ generated on the anode due to preferential electroreduction of zwitterion, which isolates Zn anode from electrolytes. Therefore, the symmetric cells with the proposed electrolyte survive long cycling stability over 600 h at 10 mA cm(-2) and 10 mAh cm(-2). The merits of zwitterion additive are further demonstrated in the Zn||V2O5 center dot nH(2)O full cell with a capacity retention of similar to 80 % after 1000 cycles.

Automated summary

A novel zwitterion additive is developed to improve the electrochemical performance and cycling stability of aqueous zinc batteries. The zwitterion forms a stable solid electrolyte interphase on the electrode surface, isolating the zinc anode from the electrolytes and enabling fast zinc ion migration. The proposed electrolyte shows promising results in symmetric cells and full cells, with long cycling stability and high capacity retention.