CAREER: Dynamic Phenomena in Complex Oxides During Electrochemical Processes

University Of California-San Diego, La Jolla CA

Investigators

Abstract

NON-TECHNICAL DESCRIPTION: Energy storage is the enabling key to the environmentally-friendly transportation and the economic deployment of renewable energy sources. All electrochemical energy storage and conversion materials function as 'living' systems (batteries, pseudocapacitors and fuel cells), within which electrons and ions are moving during charge and discharge. These electronic and ionic motions often trigger defect generation and phase transformations, and consequently result in significant changes in energy density and rate capability of the materials. Establishing the fundamental basis for these dynamical mechanisms during electrochemical processes will accelerate the creation of new synthetic materials with superior energy storage and conversion properties. TECHNICAL DETAILS: This research targets the systematic synthesis, structural characterization and properties evaluation of a series of transition metal oxides xA2MnO3(1-x)Ay(NiMn)O2 (A=Li+, Na+ the mobile species) that are capable of storing energy reversibly. These oxides have intriguing and complex features including nanometer-scale phase separation upon cycling and dynamic cation redistribution at various state of charge, that significantly affect the mobility of the guest species. The reduction-oxidation processes that occur upon releasing the guest species, not only may alter the cation distributions, but also modify the solid-solid interfaces within the material, which are critical to the transport properties as well as the structural stability of the electrodes. The developed framework can be applied as the basis for controlling the dynamic phenomena in solid-state materials for energy storage; such knowledge is critical and transformational to design and develop new materials that will allow higher and faster energy storage and longer lifetime in electrochemical energy storage and conversion systems. The broader impacts of this grant are integrated with the research objectives. The PI's education efforts include a). Vertically integrating precollegiate, undergraduate and graduate education and training through tools, practical examples and hands-on laboratory experiences b). Fostering a strong awareness and appreciation for diversity of cultural and educational backgrounds and experience and research approaches among the students to directly impact the diversity on UCSD campus, and c). Engaging in teaching and research in an international science and engineering environment, including organizing an annual international workshop and research-focused exchange program.