Pressure and Low Temperature Tolerant, High Current Density Solid Electrolyte for Propellant Grade Reactants

Precision Combustion, Inc. (PCI), in collaboration with a Research Institution, proposes to further mature a new fuel cell design utilizing a solid electrolyte technology that will meet NASAs target specifications of (i) cycling through very low temperatures (150K) to survive storage during lunar night or cis-lunar travel; (ii) recovery of 98% of its mechanical, electrical, and chemical performance post cycling; (iii) capability to process propellants and tolerate standard propellant contaminants without performance loss; (iv) capability to sustain high pressures and vibration loads; and (v) achieving current density of 300 mA/cm2 (for 500 hrs), transient currents of 750 mA/cm2 for 30 seconds and slew rates of 50 A/cm2/s. The fuel cell consists of a solid electrolyte in an innovative design configuration and internal reforming catalysts, allowing fuel cell operation with propellants. The innovative cell design and integration of reforming elements demonstrated effective fuel cell operation with tolerance to extreme temperature swing, thermal cycling, and large differential pressure. A high-performing fuel cell design was successfully fabricated and optimized in Phase I, and its performance experimentally evaluated. Extreme thermal cycling capability to 150 K, with fast heat-up to its operational temperature was also demonstrated. At the end of Phase I, a clear path towards a Phase II prototype was described, where a breadboard hardware will bedeveloped, demonstrated, and delivered to a NASA facility for demonstration testing. PCIs approach will result in a system that will be much smaller, lighter, and more thermally effective than current or prospective alternative technologies. This effort will be valuable to NASA as it will significantly reduce the known mission technical risks and increase mission capability/durability/extensibility while at the same time increasing the TRL of the fuel cells for lunar/Mars power generation and ISRU application. Precision Combustion, Inc. (PCI) proposes to mature and deliver to NASA fuel cell prototype hardware designed to meet NASA’s lunar mission target specifications of (i) cycling through very low temperatures (<150K) to survive storage during lunar night or cis-lunar travel; (ii) recovery of >98% of its performance post cycling; (iii) capability to process propellants and tolerate contaminants without performance loss; (iv) capability to sustain high pressures and vibration loads; and (v) achieving current density of >300 mA/cm2 (for >500 hrs), transient currents of >750 mA/cm2 for 30 sec and slew rates of >50 A/s/cm2. The fuel cell consists of a solid electrolyte in an innovative design and internal reforming catalysts for meeting target metrics, while allowing fuel cell operation with propellants. The innovative design and integration of reforming elements were demonstrated in Phase I for effective fuel cell operation with tolerance to extreme temperature swings, thermal cycling, and large pressure differentials. Technical Objectives:1. Optimize fuel cell configuration and reconfirm performance 2. Implement internal reforming capability within the stack assembly 3. Design and implement repeat unit assembly 4. Design, iterate, and fabricate stack assembly 5. Evaluation of the fuel cell performance to confirm functional and performance metrics 6. Initial FMEA analysis and recommendations for next stepsWork Plan:1. Review and confirm performance requirements. 2. Mature SOFC design via iterative effort. 3. Examine performance vs. objectives (specific power, durability, start/stop, thermal cycling). 4. Scale up of the SOFC. 5. SOFC performance confirmation. 6. SOFC prototypes assembly. 7. SOFC prototypes testing; Analyze performance data and suitability for NASA requirements. 8. Reporting and management. Phase II Deliverables:1. Periodic reporting and review meetings; 2. A sub-scale prototype hardware ready for TRL-5 ground demonstration; 3. Test report, FMEA analysis report, and operational specifications for the prototype. 4. Phase II Final Report with performance data.
Benefits: Potential NASA applications include future power generation systems from propellants and LOX initially for lunar bases and supporting upcoming Commercial Lunar Payload Services (CLPS). The systems have applicability over a broad range of mobile and stationary lunar surface systems, including landers, rovers, robotic rovers, and various science platforms. Key potential customers include NASA’s Space Technology Mission Directorate (STMD), NASA Glenn Research Center, NASA Johnson Space Center, and private sector customers. Non-NASA applications include automotive, defense, and distributed power generation opportunities which rely on fast start, vibration tolerance, and high efficiency. Also, SOFC-based military generators/vehicle APU’s, commercial vehicle APU’s and stationary fuel cell Combined Heat & Power (CHP) applications seeking a more cost-effective, lightweight, durable, and power dense fuel cell stack.