The effective, efficient, and environmentally friendly generation and storage of energy are important current concerns for our society and our research group. The Cairns research group studies the fundamental properties and behavior of electrodes employed in high-performance rechargeable batteries and fuel cells. We synthesize and characterize new electrode materials in order to gain a fundamental understanding of the relationships among atomic and electronic structure, electrochemical performance, and long-term stability. For example, some ambient-temperature rechargeable lithium cells exhibit incomplete utilization of the active material in the positive electrode, resulting in lower capacity per unit mass than might otherwise be delivered. In cases such as this (e.g., sulfur electrodes and metal oxide electrodes in rechargeable lithium cells), we investigate fundamental means of enhancing material utilization through modifications in the composition and structure of the electrodes, thereby increasing cell specific energy. We investigate new electrodes, electrolytes, and other cell components, and we determine the fundamental mechanisms of capacity loss of the electrodes, as well as means for eliminating the loss.
The performance of electrodes employed in fuel cells that directly react such fuels as methanol and ethanol is typically limited by slow electrochemical kinetics. The goals of our research performed on these electrodes are to synthesize new highly active electrocatalysts and characterize their kinetic and mechanistic behavior. I doing this, we identify electrode structures, electrocatalysts, and electrolyte compositions that lead to improved cell performance and lifetime.
We rely heavily upon the use of advanced research tools, such as X-ray absorption spectroscopies (XAS) using synchrotron radiation (in collaboration with Prof. S. Cramer of UC Davis), to characterize the atomic and electronic properties of new electrode materials. We pioneered the use of photothermal deflection spectroscopy for the in situ characterization of electrochemical systems. Nuclear magnetic resonance spectroscopy (NMR) has been extended (in collaboration with Prof. J. Reimer of UCB) to the study of electronically conducting electrode materials and species adsorbed on the surface of electrocatalysts. This powerful technique is used for the atomic-level study of electrode materials for both batteries and fuel cells.