NexTech Materials (United States)

Increasing demand for long-term energy storage, reduced carbon emissions, more resilient grid, and the lowest cost grid balancing solutions promotes solid oxide electrolysis cell (SOEC) and reversible solid oxide cell (RSOC) technologies. These systems can achieve high hydrogen production rates with near 100 percent stack electrical efficiency while co-electrolysis of carbon dioxide and water leads to production of syngas. RSOC can serve as a grid storage device (hydrogen production) and power production plant (provide electricity during peak demand). With over 25 years’ experience building and testing solid oxide cell materials, components and stacks, Nexceris has a proven track-record of commercializing products to major OEMs. The established manufacturing platforms at Nexceris enable smooth expansion into new applications.In this talk, development of cells, stack components and stacks will be discussed. Performance and durability improvements from single cell to short stacks will be addressed. Cells with downselected electrode sets were implemented into short stacks with active cell area of 42 cm2 and 96 cm2. Stacks were operated continuously in SOEC mode at ~1.3 V for ≥ 500 hours with <5%/kh degradation and improving. The resulting short stack demonstrations show promising baseline performance and durability platform for future cell and stack development. RSOC tests were recently initiated with dynamic operation. Nexceris’ ChromLok coatings for bipolar plates were also integrated to stacks to enhance durability.

Over the past several years Nexceris has advanced its solid oxide fuel cell (SOFC) stack technology through innovations in materials, design, and operation. Sustainable fuel cell operation of Nexceris’ lightweight stack at high current density (0.5 – 0.7 A/cm²) and fuel utilization (70 – 80%) yields both high gravimetric power density and electrical efficiency. Stack robustness against thermal gradients, thermal cycling, and one-off events has been achieved through a combination of design modifications, sealing advancements, and operational protocols. Meanwhile, Nexceris’ stack technology maintains the key advantages of its patented FlexCell planar cell design, internal reforming capability, and tolerance to sulfur impurities in military logistic fuels.Recent and ongoing work at Nexceris includes stack demonstrations in breadboard systems and at customer sites, scale-up of stack manufacturing capabilities, and the development of a 10-kW stack module, opening the door to large-scale distributed generation and energy storage applications. This presentation will provide an update on the status and capabilities of Nexceris’ SOFC stacks and cost-saving approaches to stack fabrication.

Increasing demand for long-term energy storage and reduced carbon emissions promotes solid oxide electrolysis cell (SOEC) technology. SOEC systems can achieve high hydrogen production rates with near 100 percent stack electrical efficiency while co-electrolysis of carbon dioxide and water leads to production of syngas. With over 25 years’ experience building and testing solid oxide fuel cell (SOFC) materials, components and stacks, Nexceris has a proven track-record of commercializing SOFC products to major OEMs. The established manufacturing platforms at Nexceris enable smooth expansion into SOEC applications.In this talk, development of new SOEC electrode materials, stack components and stacks will be discussed. Over 50 down-selected air and fuel electrodes were electrochemically screened on 25 cm2 electrolyte-supported single cells and compared to baseline electrodes. Multiple electrode sets provided current density over -1.5 A/cm2 at 1.3 V and 800 °C with 75 percent steam/25% percent hydrogen fuel and air. The promising electrodes were implemented into short stacks with active cell area of 42 cm2. Stacks were operated continuously in SOEC mode at 1.3-1.4 V for ≥ 500 hours. The resulting short stack demonstrations show promising SOEC baseline performance and durability platform for future cell and stack development. Co-electrolysis and water electrolysis tests were also conducted and yielded comparable performance. Nexceris’ ChromLok coatings for bipolar plates were also integrated to stacks and tested under realistic conditions.

In the development of solid-oxide fuel cells, high-performance coatings are essential to successful commercialization. Electrode coating technologies allow the cost-effective deposition of anode and cathodes on cell components at high volumes and high precision. Further, catalytic and corrosion resistant coatings for common steel alloys find application in gas delivery and fuel reforming components of the balance-of-plant. Such corrosion-resistant alloys are also combined with conductive and insulating oxide protective layers to making low-cost steel interconnectors corrosion-resistant at SOFC operating while maintaining low contact resistance and minimizing Cr volatilization. Many of the first-generation coating technologies that have found commercial implementation were designed for cell and stack operating temperatures of 750 °C and higher. In this paper, Nexceris will report on the development of new formulations designed to meet the needs of lower operating temperature SOFCs.

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Magnesium nickel silicate (MNS) has been investigated as a catalyst to convert tars and light hydrocarbons to syngas (CO and H2) by steam reforming and CO2 reforming in the presence of H2S for biomass gasification process at NexTech Materials. It was observed that complete CH4 conversion could be achieved on MNS catalyst granules at 800–900 °C and a space velocity of 24,000 mL/g/h in a simulated biomass gasification stream. Addition of 10–20 ppm H2S to the feed had no apparent impact on CH4 conversion. The MNS-washcoated monolith also showed high activities in converting methane, light hydrocarbons and tar to syngas. A 1200 h test without deactivation was achieved on the MNS washcoated monolith in the presence of H2S and/or NH3, two common impurities in gasified biomass. The results indicate that the MNS material is a promising catalyst for removal of tar and light hydrocarbons from biomass gasified gases, enabling efficient use of biomass to produce power, liquid fuels and valuable chemicals.

NexTech Materials is developing solid oxide fuel cell stacks based on its patent-pending FlexCell™ design. The FlexCell is an electrolyte-supported planar cell with unique characteristics that enable high electrochemical performance and long term durability. Demonstrated attributes of NexTech's FlexCell include scalability to large areas and tolerance to high levels of sulfur impurities in fuel. NexTech is building and testing stacks with power outputs in the 1-10 kW range, and has demonstrated that these stacks deliver targeted power outputs at high voltage and high fuel utilization.

This report documents the results of the testing that was performed to fulfill the Low Activity Waste (LAW) pretreated waste and melter feed product qualification requirements for Chemical Composition during Production as described in the Immobilized Low Activity Waste (ILAW) Product Compliance Plan and the Waste Treatment and Immobilization Plant (WTP) Contract. Meeting the product quality specifications relies on controlling the LAW melter feed preparation process and the resulting ILAW glass composition. In part, this control depends on (1) the ability of the Concentrate Receipt Vessel (CRV) system to homogenize the pretreated LAW concentrate feed, provide representative sampling of the vessel contents, measure the content level over the vessel operating range, and uniformly transfer the vessel contents, and (2) the ability of the Melter Feed Preparation Vessel (MFPV) system to homogenize the LAW melter feed after addition of the glass forming chemicals (GFCs) and uniformly transfer the vessel contents. A series of tests were conducted on a single scaled down tank, 8 feet in diameter, which was used to represent the WTP LAW CRV and the LAW MFPV. Prototypic equipment (such as radar level detectors, transfer pumps, agitators, and density probes) was installed in geometrically similar positions to those of the WTP tanks. Other equipment, which is not fully prototypic, was also installed in the tank to fully represent the WTP tank equipment arrangement. In addition, a prototypic autosampler and a hydraulically similar transfer line were installed to represent the WTP tank sampling systems. Testing was performed using simulants that represent the high and low bounds of rheology for the pretreated LAW prior to GFC addition and the LAW melter feed after GFC additions.

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