Na2[(VO)2(HPO4)2(C2O4)]·2H2O: A Promising Mixed Polyanionic Cathode Material for Aqueous Zn-Ion Batteries

Inorg Chem. 2022 Dec 19;61(50):20211-20215. doi: 10.1021/acs.inorgchem.2c03308. Epub 2022 Dec 4.

Abstract

A cathode material, Na2[(VO)2(HPO4)2(C2O4)]·2H2O, for aqueous zinc-ion batteries is synthesized by a hydrothermal method. Na2[(VO)2(HPO4)2(C2O4)]·2H2O presents a two-dimensional layered structure and sheetlike morphology, which provide fast and reversible Zn2+ insertion/extraction. Na2[(VO)2(HPO4)2(C2O4)]·2H2O delivers a high average voltage plateau (∼1.3 V), a moderate specific capacity (90 mA h g-1), and good cycle stability (100% after 100 cycles). The Zn2+ storage mechanism is investigated by in situ XRD and ex situ XPS.