A combined experimental and modeling approach is being used to facilitate an in-depth understanding of the physical processes that control degradation and failure of lithium-ion battery systems. The objective of the proposed work is to use impedance spectroscopy to identify conditions that precede failure of lithium batteries. The failure modes under investigation include the effects of temperature and the effects of overcharging and over-discharging the batteries. Previous work emphasized the interpretation of the impedance response of Polymer-Electrolyte-Membrane (PEM) fuel cells in terms of side reactions that degrade cell performance.

A series of research projects illustrate the application of electrochemical engineering to systems of practical importance. A combined experimental and modeling approach is being used to improve understanding of internal and external corrosion of pipelines used for transportation of oil and natural gas. Transient models are being developed for under-deposit corrosion inside pipelines. Electrokinetic phenomena are being exploited to enhance separation of water from dilute suspensions of clay associated with phosphate mining operations.

Electrochemical impedance spectroscopy is an experimental technique in which sinusoidal modulation of an input signal is used to obtain the transfer function for an electrochemical system. In its usual application, the modulated input is potential, the measured response is current, and the transfer function is represented as an impedance. The impedance is obtained at different modulation frequencies, thus invoking the term spectroscopy. Through use of system-specific models, the impedance response can be interpreted in terms of kinetic and transport parameters. Through a an international collaboration with scientists and engineers from France, Italy, and the United States, work is underway to improve the understanding of how impedance can be interpreted to gain insight into the physics and chemistry of such diverse systems as batteries, fuel cells, corroding metals, and human skin.

• Complete Electrochemical Laboratory (computer-interfaced instrumentation and metallographic preparation facilities)
• Cell for In-Situ Ellipsometry (Gaertner)
• Impedance Instrumentation (Solartron 1250/1286)
• Center for Solid-State Measurements (including capabilities for Deep-Level Transient Spectroscopy (DLTS) and Optically- and Thermally-Stimulated Deep-Level Impedance Spectroscopy (0S-DLZS and TS-DLZS)).