Description: The objectives of the proposed work are to increase efficiency, specific power, and specific volume of solid oxide electrolysis cells (SOEC) via performance improvements. Two approaches are proposed: (1) reducing the electrolyte thickness, and (2) using a rapid prototyping technology to create and validate optimal microstructures and compositional grading previously identified, via modeling and experimental work, to show a reduction in electrode resistance. The project goal is to improve SOEC current density at a given voltage by over 60%, which enables technological advances in electrolysis that enhance ISRU capabilities to produce power and propulsion consumables from lunar and martian carbon- or hydrogen-containing resources. For terrestrial applications, the project addresses climate concerns by enabling commercial deployment of hydrogen and synthesis gas generation using renewable energy and CO2. The OxEon team designed, constructed, and delivered a SOEC stack for the Mars In-Situ Resource Utilization Experiment (MOXIE) project for NASA's Mars 2020 mission that produced propellant grade oxygen by electrolyzing Mars atmosphere CO2. Two paths will be evaluated to decrease electrolyte thickness while retaining the robustness of the electrolyte-supported cell structure proven on MOXIE and further developed to meet redox and thermal cycle tolerance requirements in a NASA SBIR Phase II program. Air electrode supported design development will continue, and > 60% thinner electrolytes will be evaluated for electrolyte supported cells. The proposed effort uses aerosol jet printing (AJ) as a rapid prototyping approach to precisely control electrode deposition to achieve functionally and microstructurally graded compositions. Optimal electrode microstructures produced via AJ printing will be evaluated in Phase I and transferred to a screen-printing manufacturing process in Phase II.

Benefits: The principal objective of this project is to reduce specific mass (kg/kW) and specific volume (liter/kW) of a solid oxide electrolysis (SOEC) stack to enable technological advances in electrolysis that are dual use for enhancing in-situ resource utilization (ISRU) capabilities to produce power and propulsion consumables from lunar and martian carbon- or hydrogen-containing resources and enable commercial deployment of terrestrial applications of fuel synthesis. The OxEon team designed, constructed, and delivered an SOEC stack for the Mars In-Situ Resource Utilization Experiment (MOXIE) project for NASA's Mars 2020 mission. The MOXIE unit onboard the Perseverance Rover is the first ever ISRU demonstration, and it produced propellant grade oxygen by electrolyzing Mars atmosphere CO2. The SOEC stack met all the flight qualification requirements prior to launch and met operational objectives on Mars. Follow-on NASA supported projects scaled up the SOEC stacks to manned-mission size and demonstrated co-electrolysis of steam and CO2 to produce syngas and O2, and electrolysis of steam to produce H2 and O2. The stacks were operated at relevant conditions for Mars propellant production at the Jet Propulsion Laboratory (JPL) in a Mars chamber, and lunar propellant production at the Colorado School of Mines in a lunar vacuum chamber. OxEon's SOEC stack for MOXIE used an electrolyte supported cell design. The project goal is to improve SOEC current density at a given voltage by over 60%, by (1) reducing the electrolyte thickness, and (2) using a rapid prototyping technology to create and validate optimal microstructures and compositional grading previously identified, via modeling and experimental work, to show a reduction in electrode resistance. Improved performance will reduce SOEC specific mass and specific volume, enabling compact systems for space applications. The objective of this project is to reduce specific mass (kg/kW) and specific volume (liter/kW) of a solid oxide electrolysis (SOEC) stack to enable technological advances in electrolysis for space applications and to enable commercial deployment terrestrial applications of hydrogen and synthesis gas generation using renewable and carbon dioxide to address climate concerns. The project goal is to improve SOEC current density at a given voltage by over 60%, by (1) reducing the electrolyte thickness by advancing air electrode supported (AES) development and by evaluating a thinner electrolyte supported cell design, and (2) using a rapid prototyping technology to create and validate optimal microstructures and compositional grading previously identified, via modeling and experimental work, to show a reduction in electrode resistance. SOEC technology offers the most efficient pathway to produce hydrogen for terrestrial applications by electrolyzing steam. It uses two thirds of electric input to produce a unit of hydrogen compared to low temperature alkaline or proton exchange membrane based electrolyzers. In addition, it can electrolyze a mixture of steam and CO2 to produce syngas (CO+H2) that can be converted to cryogenic fuels or ambient storable fuel using Fischer Tropsch process to produce liquid hydrocarbons for further conversion to transportation fuels. Unlike low temperature electrolyzers SOEC can operate in fuel cell mode to generate power from fuels without any change to the cell and stack materials. As OxEon commercializes the SOEC technology, commercial cost targets will be achieved by a combination of manufacturing scale up and performance improvement. Under an Air Force Research Laboratory supported STTR Phase II project, OxEon developed AES cells for high performance solid oxide fuel cells to lead to lightweight stacks with high specific power (kW/kg) output, as a potential power source in an electric vertical take-off and landing (eVTOL) vehicle.