Arrhenius Behavior of the Bulk Na-Ion Conductivity in NaSc(PO) Single Crystals Observed by Microcontact Impedance Spectroscopy.

NASICON-based solid electrolytes with exceptionally high Na-ion conductivities are considered to enable future all solid-state Na-ion battery technologies. Despite 40 years of research the interrelation between crystal structure and Na-ion conduction is still controversially discussed and far from being fully understood. In this study, microcontact impedance spectroscopy combined with single crystal X-ray diffraction, and differential scanning calorimetry is applied to tackle the question how bulk Na-ion conductivity σ of sub-mm-sized flux grown NaSc(PO) (NSP) single crystals is influenced by supposed phase changes (α, β, and γ phase) discussed in literature.