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Research by: Asghar Kayani

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Dr. Asghar Kayani is a condensed matter/surface science physicist. His expertise is in the science of advanced materials, and he is a specialist in ion beam analysis of materials. His research projects are related to the development of solid oxide fuel cells (SOFCs) and hydrogen storage materials as a step towards decreasing dependence on fossil fuel with the implementation of a hydrogen economy. Briefly, the SOFC is a device to produce electricity through the chemical process of combining hydrogen and oxygen to make water. The SOFCs operate at a high temperature, typically 800-1000 oC, where the oxygen ions can readily diffuse through the solid oxide electrolyte material (zirconia). The voltage of an individual cell is relatively low, about 0.7 V, so for an application requiring several volts such as a computer or electrical instrument, individual cells are stacked together with a metal plate between each cell. Metal is the desirable material so as to keep the cost of the cell low. However, a metal plate in this mixed oxygen, hydrogen, and water environment at high-temperature quickly corrodes and fails to transfer electrical current from one cell to the next. One of Dr. Kayani's research projects is focused on improving the performance of these metal plates. This work has been recognized by NETL, and SECA to be very important to the future success of the SOFC.

A second problem with the metal plates between cells arises when they are fabricated from low-cost steels. Chromium oxide forms on the surface of the steel, and evaporates from the surface during cell operation. This chromia vapor then moves through the cell to the critical triple phase boundary region where it poisons the electrochemical process. Understanding the process by which Cr poisons the fuel cell is of interest to Dr. Kayani. He uses ion beam analysis to study the mechanism by which the chromia vapor poisons the SOFC operation. In this case, Dr. Kayani uses ion beam analysis to track oxygen incorporation into the zirconia electrolyte of the SOFC. The process uses isotopes of oxygen; much like the chemical community uses isotopes of carbon to track important processes at the atomic scale. The ability to track oxygen diffusion in an oxide material is difficult, but can be accomplished by using ion beam techniques.

Another project that interests Dr. Kayani is achieving lower operating temperatures for the SOFC by depositing thin films of yttria-stabilized zirconia for the electrolyte and/or by fabricating materials that can conduct oxygen ions at lower temperature. He is working in collaboration with the scientists at Montana State University (MSU) and Arcomac Surface Engineering in Bozeman, MT, to contrast the performance of zirconia films fabricated with different thin film deposition techniques, such as rf magnetron sputtering and filtered arc deposition

Achieving the goals of the hydrogen economy requires improving the ability to store large quantities of hydrogen, and to reversibly and quickly charge or discharge hydrogen from the storage medium. This project consists of basic research to understand and improve the kinetics of the hydrogen absorption/desorption process for new materials using plasma coating or surface modification treatments. The program is designed from the outset to accommodate industrial scale production. Specifically, the storage capacity and charging/discharging kinetics of hydrogen in bulk novel materials is characterized, and contrasted to the performance of similar materials synthesized with nanoscale coatings deposited using magnetron sputtering and a filtered arc plasma deposition process. This research using magnetron sputtering and plasma deposition of coatings technology to produce the materials allows Dr. Kayani to better understand the dependence of the hydrogen absorption/desorption kinetics on material microstructure, composition, and impurities/dopants by means of optical and electron spectroscopy and ion beam analysis techniques.

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