ABSTRACT: Globe warming and energy security are two major challenges the world is facing today. To preserve our environment and energy resource, it is imperative to maximize the utilization of existing fuels while exploring renewable sources. Fuel cell and lithium metal battery as the next-generation high-efficiency energy conversion and storage devices have attracted a great deal of attentions in recent years. This presentation summarizes some recent progresses in my laboratory in these two research areas.
A major hurdle for widespread commercialization of fuel cell is its high cost primarily due to the use of platinum as the electrocatalysts. Finding inexpensive and stable material to replace the precious metals has been one of the ultimate goals in the fuel cell research for decades. Recently, our laboratory has pioneered several new approaches to produce highly efficient, “support-free” non-precious metal catalysts by using metal-organic frameworks (Ma, et. al. Euro J. Chem. 2011, Zhao et. al. Adv. Mater. 2014), porous organic polymers (Yuan, et. al. Angew. Chem. 2013), and more recently nanofibrous network as the precursors (Shui, et. al. Proc. Natl. Acad. Sci., 2015) The new catalysts demonstrated high activities under fuel cell operating conditions, approaching to that of platinum. In this presentation, we will discuss the design and synthesis of these catalysts, as well as their catalytic mechanism and active site formation. Novel electrode architectures with improved mass/charge transfers will also be discussed.
Li-air battery also garnered many attentions due to its high theoretical energy storage capacity. At Argonne, we developed synchrotron X-ray based, spatiotemporal techniques such as microfocused X-ray diffraction (m-XRD) and tomographic (m-CT) methods to investigate the phase and structural changes inside Li-air battery in real time and under actual operating conditions. (Shui, et. al. Nature Comm. 2013; Shui, et. al. J. Am. Chem. Soc. 2012). We were able not only to decipher the different electrochemistries at individual electrode, but also to generate a holistic view on their interdependences to the overall cell performance. This knowledge has provided new insights for on the catalytic mechanism in Li-air battery and potential direction for new material/electrode design. These works are supported by US DOE Office of Sciences and Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office.
Bio-Sketch: Di-Jia Liu is a staff scientist at Argonne National Laboratory. He received his B. S. degree from Peking University and Ph. D. degree in Physical Chemistry from The University of Chicago in 1987. After two-year postdoctoral research at University of California at Berkeley, he joined Honeywell International (formerly AlliedSignal) in 1990 and led various R&D projects in fuel cell, environmental catalysis and advanced material characterization. He was the lead scientist in developing a state-of-the-art ozone converter for Boeing 777 aircrafts and was recognized by AlliedSignal Corporate Technical Achievement Award and 2000 USA Today Quality Cup. Dr. Liu joined the Chemical Sciences and Engineering Division of Argonne National Laboratory in 2002 and his current interests include non-precious metal fuel cell catalysts, hydrogen production and storage, lithium-air battery and synchrotron x-ray characterizations. He won Argonne National Laboratory Pacesetter Award, DOE Office of Sciences Outstanding Mentor Award and DOE Hydrogen Sorption Center of Excellence Team Award. He has over 90 peer reviewed publications, 29 granted US patents and patent applications and numerous presentations at the international conferences. He also serves as the US DOE representative at Fuel Cell Material Annex under Advanced Fuel Cell Implementation Agreement of International Energy Agency.