From a 3D protonic conductor VO(H2PO4)2 to a 2D cationic conductor Li4VO(PO4)2 through lithium exchange

Li4VO(PO4)2 was synthesized by a lithium ion exchange reaction from VO(H2PO4)2. The structure, determined from neutron and synchrotron powder diffraction data, changes in dimensionality from 3D to 2D. VO(H2PO4)2 exhibits a protonic conductivity of 10−4 S/cm at room temperature while Li4VO(PO4)2 is a lithium conductor.