Operando pH measurements decipher H+/Zn2+ Intercalation chemistry in high-performance aqueous Zn/δ-V2O5 Batteries
Autors: Xu Liu, Holger Euchner, Maider Zarrabeitia, Xinpei Gao, Giuseppe Antonio Elia, Axel Groß and Stefano Passerini.
Summary: Vanadium oxides have been recognized to be among the most promising positive electrode materials for aqueous zinc metal batteries (AZMBs).To shed light on the intercalation mechanisms, high-performance δ-V2O5 is investigated as a model compound. An operando pH determination method is developed and used toward Zn/δ-V2O5 AZMBs. This method indicates the intercalation of both H+ and Zn2+ into δ-V2O5 and uncovers an unusual H+/Zn2+-exchange intercalation–deintercalation mechanism. Density functional theory calculations further reveal that the H+/Zn2+ intercalation chemistry is a consequence of the variation of the electrochemical potential of Zn2+ and H+ during the electrochemical intercalation/release.