Physics Dept Seminar

November 8, Friday (*SPECIAL DAY*)

Correlated Dynamics and Non-Arrhenius Behaviors of Solid Ionic Diffusion

Prof. Hong Fang

Rutgers Univ. - Camden

(Materials Physics, Host: Ken Ahn)

Time: 11:45am-12:45pm with 11:30am teatime

*Room: 407 Tiernan (** SPECIAL ROOM **)

Ionic diffusion in solid materials is fundamental to understanding numerous important phenomena in materials science, including nucleation, crystal growth, alloying, sintering, hardening, phase transitions, oxidation, fracture, plastic flow, and more. Solids exhibiting high ionic diffusivities are key components in batteries, fuel cells, sensors, and supercapacitors. Mixed ionic–electronic conductors such as organic-inorganic hybrid perovskites can serve as the light absorber in advanced solar cells. Behaviors of the ionic diffusion are vital to the performance and stability of these devices. Current modeling of the ionic diffusion is largely based on random-walking ions with independent jumps. A dominant mechanism of diffusion is often assumed so that the calculated diffusivity against temperature follows the Arrhenius law. However, with novel compositions and a combination of defects, emerging solid ionic conductors contain diffusion mechanisms beyond the simple random-walking model. Mechanisms of such are often temperature-dependent, leading to various non-Arrhenius behaviors of materials. In this talk, I will report our recent modeling studies on the ionic diffusion in newly developed solid-state ionic conductors, featuring strong correlated dynamics and non-Arrhenius behaviors. New diffusion mechanisms with correlation effects that can support high ionic diffusivities in solids will be presented, together with the theoretical tools of characterizations.