Chemical Engineering
 

Stuart B. Adler
Assistant Professor

Contact Information
355 Benson Hall
Box 351750
Seattle, WA 98195-1750
Phone: 206-543-2131
Fax: 206-685-3451
E-mail: stuadler@u.washington.edu

Education

B.S.E., University of Michigan, 1987.
Ph.D., University of California at Berkeley, 1993.

Research Interests

Solid-State Electrochemical Engineering, Electrocatalysis, Ionic Transport, Ceramics, Fuel Cells.

The research of my group seeks to better understand the thermodynamic, kinetic, and transport properties of solids, and how these properties relate to electrochemical devices and processes. Electrochemical solids are used in a wide spectrum of applications, from sensors, batteries, and fuel cells to large-scale separations and processing of liquid fuels.

In many cases, electrochemical applications are developed or optimized using empirical data, or rules of thumb derived from well-studied systems. The purpose of our work is to provide improved measurement methods and analysis techniques that link device or process performance more directly to the properties and geometry of constituent materials. This approach allows us to better design electrochemical systems, choose or screen candidate materials, diagnose device degradation, and develop appropriate fabrication methods.

To fully understand the electrochemical properties and behavior of solids, we must bring together two well-established ways of viewing physical phenomena. The continuum view (e.g. concentration, potential, flux) is well established for understanding aqueous electrochemical systems, but lacks direct applicability to solids, whose properties differ from liquids in fundamental ways. The atomistic view (e.g. crystal and electronic structure, atomic motion, microstructure) provides a basis for understanding solid properties, but lacks direct linkages to electrochemical modeling and measurement. In order to bridge atomistic and continuum understanding, we must address a spectrum of length scales, both experimentally and theoretically. General questions include:

As with many fields, progress in solid-state electrochemical engineering requires a two-pronged approach involving both experiment and modeling. On the experimental side, we employ transient measurements of system electrochemical behavior (a.c. impedance and current-interruption) in order to separate complex overlapping physical phenomena by timescale. We also develop novel methods of isolating and measuring the electrochemical properties of solids independently of the electrochemical system; this approach allows us to develop (and explore the validity of) electrochemical models without relying on adjustable parameters. These measurements include thermodynamic, kinetic, and transport measurements under unusual temperature and atmospheric conditions (using TGA, coulometry, magnetometry, and dilatometry), and materials characterization (using scanning electron microscopy, elemental spectroscopies, X-ray diffraction, and secondary ion mass spectrometry). Finally, some of our more recent work involves measuring the electrochemical behavior of micro-fabricated model systems, where we have control over length scales governing transport, reaction, and catalysis. This work has been done in collaboration with our Micro-Electronics Design Center.

On the theoretical side, our approach has been to break-down electrode reactions or device operation into individual physical processes, which can be modeled based on independent measurement. Some of our work involves analytical models of porous electrode behavior using perturbation methods. We have also begun to tackle nonlinear systems using a hybrid approach, treating the steady-state or step-transient equations with numerical finite-element methods, but preserving the analytical approach for small-amplitude perturbations (such as a.c. impedance). This approach allows us to best relate electrochemical behavior to independently-measurable parameters governing reaction, transport, and thermodynamics. On the atomic level, we have also been working on new theoretical treatments of defect and electronic structure that help us better explain the thermodynamic properties (oxygen exchange and chemical expansion) of mixed conducting oxides. In the future, we hope to use atomic modeling methods in conjunction with atomic and electronic-structure measurements (magnetometry and/or Solid-State NMR) to better rationalize or extrapolate properties of materials.

Selected Recent Publications

"Chemical expansivity of electrochemical ceramics", S. B. Adler, Journal of the American Ceramic Society 84, 2117-2119 (2001).

"Limitations of charge-transfer models for mixed-conducting oxygen electrodes", S. B. Adler, Solid State Ionics 135, 603-612 (2000).

"Reference electrode placement and seals in electrochemical oxygen generators", S. B. Adler, B. T. Henderson, M. A. Wilson, D. M. Taylor and R. E. Richards, Solid State Ionics 134, 35-42 (2000).

"Mechanism and kinetics of oxygen reduction on porous La1- xSrxCoO3-delta electrodes", S. B. Adler, Solid State Ionics 111, 125-134 (1998).

"Fundamental issues in modeling of mixed-conductors (a rebuttal to comments on ''electrode kinetics of porous mixed-conducting oxygen electrodes'')", S. B. Adler, J. A. Lane and B. C. H. Steele, Journal of the Electrochemical Society 144, 1884-1890 (1997).

"Electrode kinetics of porous mixed-conducting oxygen electrodes", S. B. Adler, J. A. Lane and B. C. H. Steele, Journal of the Electrochemical Society 143, 3554-3564 (1996).

"High-temperature O-17 NMR as a probe of electron localization and structure in transition metal oxides", S. B. Adler and J. A. Reimer, Solid State Ionics 91, 175-181 (1996).

"Chemical-structure and oxygen dynamics in Ba2In2O5", S. B. Adler, J. A. Reimer, J. Baltisberger and U. Werner, Journal of the American Chemical Society 116, 675-681 (1994).

"Effects of long-range forces on oxygen-transport in yttria- doped ceria - simulation and theory", S. B. Adler and J. W. Smith, Journal of the Chemical Society-Faraday Transactions 89, 3123-3128 (1993).

Go to link Recent M.S. Theses
Go to link Recent Ph.D. Dissertations