1. Proton Conduction Mechanisms in Superionic Phases of Phosphate-Based Solid Acids
Cristian E. Botez
Department of Physics, The University of Texas at El Paso El Paso, TX 79968
The proton conductivity of MH2PO4–type (M=Cs, Rb) solid acids increases by several orders of magnitude upon heating above a temperature threshold (superprotonic behavior), but the atomic-scale processes responsible for this phenomenon have not been discovered.
Our study is aimed at determining the crystal structures and, ultimately, the microscopic mechanisms that govern this enhanced proton conduction.
So far, using high-pressure synchrotron X-ray diffraction, we have uncovered the structural modifications associated with the superprotonic transition in CsH2PO4 and RbH2PO4 (including the details of the crystal structure of the high-pressure high-temperature cubic CsH2PO4 phase).
Next, we will use neutron spectroscopy methods in an attempt at finding how do the protons travel so efficiently through the crystal structure of the high-temperature superprotonic phase.
Pressure ~ 1 GPa
high-temperature cubic CsH2PO4 phase