Lora B. Thrun

Oxide Protective Coatings for Solid Oxide Fuel Cell Interconnects

The oxidation kinetics of manganese cobalt (Mn,Co)3O4 spinel (MCO) coated AL 441-HP components have been determined by isothermal cyclic oxidation experiments over a range of temperatures from 800 to 1000 °C. Acceleration factors based on calculated parabolic rate constants were used to relate the long-term stability performance of the MCO coating under accelerated electrical testing at 900 °C to effective lifetimes at lower operating temperatures. At 750 °C an effective lifetime for the MCO coating on AL 441-HP exceeding 40,000 hours was predicted.

Amperometric NO x Sensor Based on Oxygen Reduction

A novel ceria-based amperometric NO_x and NH₃ sensor was investigated. The sensor consisted of gadolinium-doped ceria electrolyte membrane with (La_0.60Sr_0.40) (Co_0.20Fe_0.80)O_3-δ (LSCF) electrodes applied to opposite sides. The assembly operated in combustion exhaust streams with higher sensitivity to both NO_x and NH₃, less dependence on oxygen partial pressure, and faster response than previously reported. The sensor had an operational temperature range of 200 °C-550 °C and was resistant to common exhaust gas contaminants, such as steam, CO₂, and sulfur oxides. Electrochemical testing and in-situ DRIFTS studies showed NOx adsorption on the sensor causing accelerated kinetics for oxygen reduction reaction (ORR) whereby adsorbed NOx species acted as a catalyst for an alternative ORR pathway, thus enabling an amperometric sensing mechanism.

Final Report, Validation of Novel Planar Cell Design for MW-Scale SOFC Power Systems

This report describes the work completed by NexTech Materials, Ltd. during a three-year project to validate an electrolyte-supported planar solid oxide fuel cell design, termed the FlexCell, for coal-based, megawatt-scale power generation systems. This project was focused on the fabrication and testing of electrolyte-supported FlexCells with yttria-stabilized zirconia (YSZ) as the electrolyte material. YSZ based FlexCells were made with sizes ranging from 100 to 500 cm2. Single-cell testing was performed to confirm high electrochemical performance, both with diluted hydrogen and simulated coal gas as fuels. Finite element analysis modeling was performed at The Ohio State University was performed to establish FlexCell architectures with optimum mechanical robustness. A manufacturing cost analysis was completed, which confirmed that manufacturing costs of less than

Validation of Novel Planar Cell Design for MW-Scale SOFC Power Systems

50/kW are achievable at high volumes (500 MW/year).

Manufacturing Cost Analysis for YSZ-Based FlexCells at Pilot and Full Scale Production Scales

This report describes the work completed by NexTech Materials, Ltd. during a three-year project to validate an electrolyte-supported planar solid oxide fuel cell design, termed the FlexCell, for coal-based, megawatt-scale power generation systems. This project was focused on the fabrication and testing of electrolyte-supported FlexCells with yttria-stabilized zirconia (YSZ) as the electrolyte material. YSZ based FlexCells were made with sizes ranging from 100 to 500 cm{sup 2}. Single-cell testing was performed to confirm high electrochemical performance, both with diluted hydrogen and simulated coal gas as fuels. Finite element analysis modeling was performed at The Ohio State University was performed to establish FlexCell architectures with optimum mechanical robustness. A manufacturing cost analysis was completed, which confirmed that manufacturing costs of less than

Amperometric electrochemical cells and sensors

50/kW are achievable at high volumes (500 MW/year). DISCLAIMER

AMPEROMETRIC ELECTROCHEMICAL SENSORS, SENSOR SYSTEMS AND DETECTION METHODS

Significant reductions in cell costs must be achieved in order to realize the full commercial potential of megawatt-scale SOFC power systems. The FlexCell designed by NexTech Materials is a scalable SOFC technology that offers particular advantages over competitive technologies. In this updated topical report, NexTech analyzes its FlexCell design and fabrication process to establish manufacturing costs at both pilot scale (10 MW/year) and full-scale (250 MW/year) production levels and benchmarks this against estimated anode supported cell costs at the 250 MW scale. This analysis will show that even with conservative assumptions for yield, materials usage, and cell power density, a cost of

Hydrogen sensitive composite material, hydrogen gas sensor, and sensor for detecting hydrogen and other gases with improved baseline resistance

35 per kilowatt can be achieved at high volume. Through advancements in cell size and membrane thickness, NexTech has identified paths for achieving cell manufacturing costs as low as

Amperometric solid electrolyte gas sensor and detection method wherein the sensing electrode comprises at least one tungstate or molybdate compound

27 per kilowatt for its FlexCell technology. Also in this report, NexTech analyzes the impact of raw material costs on cell cost, showing the significant increases that result if target raw material costs cannot be achieved at this volume.