In light of global warming concerns and the ever-present need for domestic energy sources, never before has there been a call for the development of new energy systems that operate efficiently and cleanly on renewable fuels (like biofuels and potentially hydrogen) and abundant domestic fossil fuels. One such energy system is solid-oxide fuel cell, or SOFC technology. SOFC's offer many advantages over other fuel energy conversion devices due to its high efficiency, high heat-recovery capabilities and fuel flexibility. The operation of SOFCs depends upon the reduction and incorporation of O 2- ions into an electrolyte material, and the transport of these ions across the electrolyte to the anode where the fuel is oxidized. SOFCs operate at higher temperatures (500-1000°C) where the electrolyte diffusivity of O 2- ions is high, while the electrolyte membrane remains an electronic insulator. The electrodes on each side of the electrolyte membrane provide both an electrical connection and electrocatalytic sites for oxygen reduction (cathode electrode) and fuel oxidation (anode electrode).
Smart sensor materials are essential to provide real-time accurate measurements
under challenging extreme harsh environment conditions for various applications.
We work on developing strategies and processing methodology to fabricate and evaluate “peel and stick” inductor-capacitor (LC) based passive wireless sensor for harsh environmental application. Current work also involves evaluating various inorganic and filled polymers for polymer derived ceramics for 2D/3D printing application.
Ionic Polymer-Metal Composites (IPMCs), as electromechanical sensors and actuators, offer large displacement responses to low applied voltages. These materials are being proposed for use in soft robotic actuators, artificial muscles, wearables, and dynamic sensors. Still, challenges exist involving ionic electroactive material’s sensitivity to temperature, humidity, and electrical load history. This research investigates the pattern-ability of these thin-film (~50 -150 μm thick) actuators and characterize their electroactive response. Currently, actuators comprising of Nafion impregnated with dispersed platinum and/or silver nanoparticles are being fabricated in various geometries for dynamic flow control schemes.
Increasing environmental pressures to regulate emission gases has created an explicit requirement for the development of chemical sensors and sensor arrays to detect gases such as CO/CO 2, NO x, H 2S, and SO x, within high-temperature environments (>500°C). These sensors will enable an inexpensive implementation of sensor nets for in situ gas testing for three-dimensional fuel and emission maps within various industrial energy applications, such as current coal-fired power plants. The micro-sensors may also be applied within future Integrated Combined Cycle Gasification (IGCC) systems and direct-coal fuel cell generator systems, providing instantaneous feedback on fuel utilization and emission control systems.
Current chemical sensors based on chromatography, electrochemistry, and spectroscopy are not available to suit the desired application, cost, and performance within the proposed high temperature and harsh chemical environmental targets. Our research investigates chemi-resistive sensors that are based on stable high-temperature, semiconducting oxides which demonstrate a change in resistance due to surface interaction with select chemical species. In order to achieve the above-mentioned performance and application targets, our work concurrently addresses issues relating to sensor stability, selectivity, and miniaturization of the chemi-resistive sensors.
The objective of our research is to design a suitable battery that can maintain its structural integrity while enduring extreme stresses and environments, such as a large temperature gradients and large forces. In order to achieve these goals, our work focuses on the incorporation of active battery components within structural composite architectures. This process has the ultimate goal of merging the power supply directly into the structure of unmanned air vehicles. By doing this, UAVs will be more functional and versatile due to massive volume, and potentially weight, reductions.
One route is to develop a solid-state Li-ion battery based on a glass-ceramic composite structure that can be reversibly operated above 4 V with >200 mAhg -1 discharge capacity at ~25°C. Our research focuses on the synthesis and characterization of solid-state Li-ion electrolytes and compatible solid-state electrode systems, and the incorporation of these solid-state batteries within the vehicle support structure.
Another route is to develop a composite multifunctional Li-ion battery with tunable mechanical properties depending on the composition and microstructure of the battery components. Combining the mechanical structure and the battery function into a single architecture permits improvements in performance not possible through the individual components. The design of composite multifunctional batteries for optimal performance involves precise selection of materials, architectures, and the interconnection between the battery components.