Dynamics of mobile ions in superionic conductors: Comparison with liquid electrolytes and water

The dynamics of mobile ions in superionic conductors (SICs) are discussed through electrochemical impedance spectroscopy via Nyquist plots (NPs). A dimensionless NP is newly introduced, as a new analytical technique, in SICs, which are compared with those found in liquid electrolytes (LEs) and pure water (PW). It is found that the background dielectric constant of the host materials significantly affects the shape of the NP. This fact leads to different shapes of NPs among SICs, LEs, and PW, while the postulated diffusion dynamics (random-barrier classical hopping of free ions) are the same for all these material systems. The present new discovery may shed light on a clear understanding of the dynamics of ionic diffusion of SICs.