第16回 東北イオニクス研究会
Prof. Nicola Perry (University of Illinois, USA) 講演会
日 時： 2019年6月12日（水） 16:00~17:00
場 所： 片平キャンパス 多元物質科学研究所 事務棟大会議室
講演題目： Toward mixed conducting oxides by design for durable, efficient energy conversion
講演概要： Oxides that can “breathe” and transport oxygen and/or steam are vital components of elevated temperature electrochemical energy conversion and storage devices. Ideally these materials should exhibit rapid surface exchange kinetics and transport, for efficiency, and minimal chemical expansion during stoichiometry changes, for durability. However, in practice, surfaces are almost ubiquitously poisoned by large cation segregation leading to sluggish surface exchange kinetics, and chemical strains are readily large enough to cause mechanical failure. In order to identify which aspects of structure can be controlled to tailor these contributions to efficiency and durability, we synthesize and measure model bulk and thin film oxides with systematically varied microstructure, crystallinity, crystal symmetry, and defect chemistry. In this talk I will focus on some of our recent work on mixed ionic and electronic conducting perovskites, where we are identifying structural factors that can be incorporated by design to tailor the surface exchange kinetics and chemical expansion. We are learning how to increase the surface exchange kinetics by minimizing cation segregation through non-equilibrium growth and in situ crystallization. Similarly, we are observing how to decrease the coefficient of chemical expansion through tailored charge localization, crystal distortions, and nanostructuring. I will also highlight technique advances that enable these findings, such as in situ optical transmission relaxation and nanoparticle dilatometry.