Q&A With R. Edwin Garcia

Considering computational materials engineering

R. Edwin Garcia, assistant professor of materials engineering, has been at Purdue since 2005. He has a BS in physics from the University of Mexico (1996), and an MS in Materials Science and Engineering (2000) and a PhD in Materials Science (2002) with a minor in applied mathematics, both from the Massachusetts Institute of Technology. He was a postdoctoral researcher at the National Institute of Standards and Technology in the Center for Theoretical and Computational Materials Science between 2003 and 2005. He and his wife, Lindsay Haugland, have four children.

Above is a simulation of lithium-ion distribution in a rechargeable battery. The top section (a) corresponds to "as-received" cross-section of portable power source. The middle section (b) embodies the digitized cross-section. The green phase corresponds to particles of graphite (anode) material, the red phase to lithium cobalt oxide (cathode), and the background black material to polymer-based electrolyte. The bottom section (c) illustrates the lithium-ion distribution at the end of a single discharge cycle over a period of one hour. Particle-particle electrochemical interactions are readily observed and impact on the delivered macroscopic power density. Calculation performed by Madeliene Smith (BSMSE 2008).

Q: Were you born to engineer?

A: I was strongly influenced in choosing engineering by my father, who was a physics professor at the University of Mexico. He studied the atomic aspects of matter. I was in middle school during the Mexico City earthquake of 1985, which closed down our schools for seven months. My father made me and my brother keep studying. He took us to the library, bought a book on Euclidian geometry and asked us to explain a theorem a day. This daily exercise taught us how to think systematically and critically. I studied physics at the baccalaureate level, but, partially because I grew up in an underdeveloped country, I felt there was a greater need for people with technical knowledge, that it was important for me to study something more applied than physics. I became interested in looking at the ways in which materials organize themselves, understanding how materials and devices work, optimizing, and engineering them.

Our research group at Purdue, the Laboratory for the Computation of Materials and Devices, applies theoretical and computational methods to understand the relations between material properties and microstructures in order to tailor their properties and to optimize their associated reliability. I am a computational materials engineer. Modeling provides guidelines and is a very powerful tool in combination with experiments to shorten materials and devices design. At the end of the day, the combination is very powerful, inexpensive, and results in a better product.

Q: Describe your current work with rechargeable lithium ion batteries?

A: I am focusing now on the design of energy-related materials and devices by starting from the most fundamental thermodynamic principles. I began working on this during my doctoral studies at MIT by accident when a very good friend challenged me to engineer a battery. I am now looking at engineering batteries for better efficiency by removing the diffusion barrier between the cathode and anode. I am looking at the best particle size distributions and spatial configurations and eliminating or harnessing defects to optimize power and energy density. The uniqueness of my approach relies on the possibility of resolving the topological defects of the device by using both real and computer-generated materials. We are also applying similar approaches to engineer solid oxide fuel cells, thermoelectric generators, and phosphor-free light emitting devices. In all these cases, we start from the laws of thermodynamics, we incorporate the relevant transport mechanisms, and after understanding the processes that control their response and efficiencies, we propose new designs and guidelines to optimize them.

Q: Can thermodynamics be fun?

A: I am always very excited about discovering new things and sharing that excitement with students. I teach undergraduate thermodynamics, which is often thought of as a dry topic. My personal goal is to remove that prejudgment from the subject and have students appreciate that you can do exciting, applicable things by starting from well-rounded fundamental principles. I give them assignments—make a spinodally decomposing tomato soup, engineer a raincoat with a fabric that breathes, propose the conditions to heterogeneously grow a Si-Ge film, or to cast the iron of your choice. The class is oriented to describe real-life situations, and the textbook, Introduction to the Thermodynamics of Materials by Purdue Materials Engineering Professor David Gaskell, is the ideal starting point. Thermodynamics prepares students for a technology-oriented world but it can also be used in everyday situations, because thermodynamics is universal.

Q: Describe your work in one sentence.

A: I consider myself an explorer, discovering new things every day, something useful that the industrial and scientific community can use.

- Linda Thomas Terhune