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In various embodiments, techniques for fabricating solid oxide fuel cells utilize setter plates composed of or having outer surfaces composed of materials unreactive with species found in the layers of the cell.
Systems for creating electrodes for polymer electrolyte membrane fuel cells include an XY stage having a heated vacuum table physically coupled to the XY stage. The vacuum table has a working face with a plurality of channels formed therein to communicate vacuum pressure from a port coupled to a vacuum source to the channels. A sheet of perforated heat-conductive material has staggered holes configured to evenly distribute the vacuum pressure from the channels through the perforated sheet. A heat-conductive wire mesh is placed over the perforated sheet, and has openings smaller than the staggered holes such that a membrane material placed on the wire mesh is not deformed by the vacuum pressure. A nanopipette or micropipette coupled to a pump is configured to deposit electrode ink onto an exposed surface of the membrane material as the controller device causes the XY stage to move the vacuum table to control deposition of the electrode ink onto the surface of the membrane material.
In various embodiments, techniques for fabricating solid oxide fuel cells utilize setter plates composed of or having outer surfaces composed of materials unreactive with species found in the layers of the cell.
For the first time a long-term (500 h) durability study in direct methanol fuel cells (DMFCs) is carried out on a Platinum Group Metal-free (PGM-free) cathodic electro-catalyst commercially available on market. The electro-catalyst is tested for 500 h at a fixed cell voltage (0.3 V), recording the polarization curves during the operation. A drastic decrease in performance is observed after the first 100 h (from 220 to 75 mA cm –2 ); afterwards, the decrease is flatter, passing from 75 to 25 mA cm –2 (at 500 h). The causes of this performance degradation are investigated by postmortem physicochemical analyzes, such as X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with X-ray energy dispersive analysis (EDX). Finally, possible reasons of degradation are indicated to be PGM-free catalyst aggregation, carbon and nitrogen species decrease, Ruthenium dissolution and migration from the anode to the cathode, poisoning both membrane and cathode catalyst.
The evolution of Pt nanoparticles supported on carbon nanotubes is analyzed before and after electrochemical potential cycling, using identical location aberration-corrected transmission electron microscopy, for applications in proton exchange membrane fuel cells. The work is focused on the half-cell accelerated stress test protocol of potential cycles ranging between 1.0 and 1.5 V RHE to represent the start-up/shutdown settings of a fuel cell vehicle. The research work reveals that particle migration and coalescence are key mechanisms for a reduction in the Pt nanoparticle surface area at the early stages of potential cycling. Further, the mechanism for particle movement and coalescence is attributed to carbon corrosion, catalyzed either by Pt or by bulk corrosion of the carbon nanotubes. Carbon corrosion results in the appearance of carbon vacancies at the carbon nanotube/Pt nanoparticle interface during cycling, as well as the formation of edge and surface defects. During cycling, the concentration of the dissoluble Pt increases. As soon as a significant amount is reached, subnanometer/atomic clusters emerge on the carbon nanotube support, which can move and coalesce, or redeposit on the surface of larger particles through Ostwald ripening.
An effective strategy for generating combined heat and power (CHP) systems is to use the combustion of hydrocarbons to provide fuel reforming and heat production for solid oxide fuel cell (SOFC) operation. Though tubular SOFCs (tSOFCs) are well suited to the thermal cycling associated with combustion systems, they have a geometric limitation which requires significant alteration to the combustion chamber. These alterations can be eliminated by producing an anode supported internal cathode-tSOFC (IC-tSOFC) which can be directly integrated into the chamber with minimal alterations. Novel methods used to produce IC-tSOFCs are discussed in this work. Scanning electron microscopy (SEM) and performance characterization are used to analyze fabricated cells. Finally, with a peak power density of 369 mW∙cm –2 , and an open circuit voltage (OCV) of 0.98 V, it is confirmed that novel production methods for IC-tSOFCs have been successful.
This report highlights recent changes in the FCEB market, status updates for deployments, and a detailed performance evaluation of a large fleet of FCEBs operated by Foothill Transit in California during the period from June 2023 to December 2024.
The global effort to introduce polymer electrolyte fuel cells for clean and renewable energy to the market is increasing the demand for high performance, robust and affordable membrane electrode assemblies (MEAs). There is not yet a standard method for large scale production of MEAs, or the methods employed are generally unsatisfactory in terms of quality and performance. A large number of published data of newly developed catalyst and electrolyte materials, claim to improve the state of the art, but are often not fully comparable due to different experimental studies and experimental designs. This article summarizes the trends in material developments and emerging MEA-manufacturing techniques. The materials and techniques are systematically compared in terms of cell performance and scalability. Current and future scientific challenges are identified and analysed based on published findings over the past five years. Finally, the results of the cited papers have been quantitatively compared to each other and to the internal benchmarks used in each cited work to provide a complete picture of the state of the art in PEFC MEA manufacturing.
A multiscale mechanistic damage model for solid oxide fuel cell (SOFC) ceramics that combines micromechanics of stiffness reduction due to material porosity change and microcracking with a continuum damage mechanics (CDM) description for the evolution of microcracks up to fracture is developed in this work. The model also accounts for volumetric swelling of the anode due to redox cycling. Porosity change and swelling during redox combined with normal operating thermomechanical loads could increase the stress, strain and damage distributions in SOFC stacks leading them to failure. The proposed model involves three governing parameters: (i) the porosity in terms of the pore or void volume fraction, (ii) material swelling magnitude prescribed at a given loading step, and (iii) the damage variable that describes microcracking caused by thermomechanical loads and swelling. Pores and microcracks in the ceramics are modeled as randomly distributed ellipsoidal inclusions with negligible stiffness by an Eshelby-Mori-Tanaka formulation combined with an inclusion orientation distribution method. Microcracking damage evolution is described by a CDM formulation. Volumetric swelling is treated in a similar way to thermal expansion in the constitutive relations. After validation and numerical checks, the damage model is used to analyze a simplified SOFC positive-electrode/electrolyte/negative-electrode (PEN) structure subjected a redox cycle in addition to thermomechanical loads experienced during normal operation of a SOFC stack.
Presentation summarizes the findings of a workshop on Hydrogen and Fuel Cells for Data Center Applications that was held in March 2019.
The motivation for this project stemmed from the challenges associated with rapidly refueling heavy-duty hydrogen fuel cell electric trucks (FCETs). Current manual refueling processes for fast refueling involve large, heavy equipment (e.g., hoses three times heavier than standard) and pose ergonomic risks and potential for equipment damage. The goal was to develop and test an autonomous fueling system to improve ergonomics, enhance safety, increase equipment durability through design improvements, and potentially speed up the fueling process. This project aimed to add to the understanding of autonomous systems in the context of heavy-duty hydrogen refueling, evaluating the technical effectiveness of potential concepts. A successfully developed system would benefit the public by facilitating the adoption of zero-emission heavy-duty transport, reducing reliance on manual labor for a physically demanding task, and potentially improving the safety and efficiency of hydrogen refueling infrastructure. The major accomplishment during the project's active period was the completion of the system-level architecture task. This involved establishing a detailed list of system requirements covering interfaces, environmental conditions, regulatory compliance, industry standards, safety, security, performance capabilities, and optional features. Five key use cases for the autonomous system were also identified. However, due to internal restructuring at Nikola, the necessary resources could not be allocated to continue the project. Consequently, Nikola opted to discontinue the project. The award was mutually terminated by Nikola and the DOE.
In the last 20 years, direct alcohol fuel cells (DAFCs) have been the subject of tremendous research efforts for the potential application as on-demand power sources. Two leading technologies respectively based on proton exchange membranes (PEMs) and anion exchange membranes (AEMs) have emerged: the first one operating in an acidic environment and conducting protons; the second one operating in alkaline electrolytes and conducting hydroxyl ions. In this review, we present an analysis of the state-of-the-art acidic and alkaline DAFCs fed with methanol and ethanol with the purpose to support a comparative analysis of acidic and alkaline systems, which is missing in the current literature. A special focus is placed on the effect of the reaction stoichiometry in acidic and alkaline systems. Particularly, we point out that, in alkaline systems, OH – participates stoichiometrically to reactions, and that alcohol oxidation products are anions. This aspect must be considered when designing the fuel and when making an energy evaluation from a whole system perspective.
The overall objective of this project was to develop a transformative Solid Oxide Fuel Cell (SOFC) building block configuration comprised of multi-stack arrays that can be utilized in large-scale power plants. This transformative design signified the benefits of lower performance degradation coupled with improved reliability, low cost, smaller packaging for easier transport and installation, and improved maintenance and field serviceability characteristics. The project goal was to design and fabricate a scalable hot module for housing an array of SOFC stacks and to demonstrate the characteristics of the module gas distribution, insulation and instrumentation, and DC power take-off. The approach was to validate the design of a stack prototype scalable to megawatt (MW) class systems using FuelCell Energy’s Compact SOFC Architecture (CSA) stacks. The scope of work was intended to design, build, and test a compact and low-cost multi-stack sub-module with flexibility to house CSA stacks and scalable to 350 kW which could ultimately be deployed in construction of MW-class systems.
H 2 /air fuel cell membrane-electrode-assemblies (MEAs) were fabricated with electrospun particle/polymer nanofiber mat cathodes (0.1 mg Pt /cm 2 or 0.2 mg Pt /cm 2 Pt/C, PtCo/C or PtNi/C) and anodes (0.1 mg/cm 2 Pt/C), where the binder was a mixture of acid-form perfluorosulfonic acid ionomer (e.g., Nafion™) and poly(acrylic acid) (PAA) carrier polymer or sodium-form PFSA with a carrier polymer of either PAA or polyethylene oxide (PEO). For the latter two cases, the water-soluble carrier was removed from the fibers after electrospinning. MEAs with Pt/C anode/cathode catalyst loadings of 0.1 mg Pt /cm2 each, an 1100 EW PFSA binder (Nafion™ dispersion), and a Nafion 211 membrane produced high power at both high and low relative humidity (RH) conditions, e.g., a maximum power density of 919 mW/cm 2 at 100% RH and 832 mW/cm 2 at 40% RH for a test at 80 °C and 200 kPa abs . The high power at low RH was attributed to nm-size pores within the fibers that trap water via capillary condensation thus maintaining a high proton conductivity of the PFSA binder in the cathode and especially the anode while minimizing/eliminating ionic isolation of catalyst particles in low water content, poorly conductive binder. At the same time, micro-porosity between fibers in the cathode allows for fast removal of electrogenerated water, thus minimizing cathode flooding. Nanofiber MEAs with Pt alloy catalyst cathodes also performed well, where a fibrous PtCo/C catalyst cathode at a loading of 0.1 mg/cm 2 produced 20% more power than a conventional powder cathode MEA, e.g., a maximum power density of 1,045 mW/cm 2 vs. 869 mW/cm 2 at 80 °C, 100% RH, and 200 kPa abs , and a PtNi/C fiber cathode MEAs prepared with Na+-form Nafion + PEO generated a maximum power of 820 mW/cm 2 at 40% RH. Fiber electrode MEAs with a neat Nafion binder (prepared from Na+-form Nafion + PEO or PAA) where the cathode Pt loading was ~0.1 mg/cm 2 exhibited a 25% loss in maximum power at 30,000 metal dissolution cycles, as compared to a 12% loss when the cathode binder was H+-form Nafion + PAA. The performance of a fiber mat electrode MEA with Pt/C catalyst (0.2 mg/cm 2 cathode loading and 0.1 mg/cm 2 anode loading) was excellent. At 80 oC and 200 kPa abs , the maximum power density was 1104 mW/cm 2 . The maximum power was independent of feed gas humidity for 40 < RH < 100%. The power loss after a metal dissolution AST (30,000 voltage cycles) was only 13%.
Summary of progress and accomplishments for an NREL-led project to improve performance and durability of alkaline membrane fuel cells (AMFCs).
A major challenge with complex cyber-physical systems stems from long model computational time that creates a mismatch between the model system and the physical system. The numerical modeling of solid oxide fuel cells (SOFCs) presents particular challenges due to the highly coupled nature of the underlying equations and the multiphysics needed to fully resolve their behavior during a transient event. To this end current approaches revolve around splitting the computational efforts into resolving temperature effects and resolving electrochemical effects. Current methods employed for the transient simulation of an SOFC for implementation in the Hybrid Performance (HyPer) facility cyberphysical plant at the National Energy Technology Laboratory reveal a distinct need for accelerated results with a high degree of stability. To this aim, an investigation into the computational time for the code reveals that the underlying electrochemical algorithm takes an order of magnitude more time than its thermal counterpart and has a tendency to vary in terms of iteration time and as such a rework of the underlying system is proposed. The primary method for accelerated electrochemical algorithm solutions is to employ higher order root finding recipes for the resolution of the highly coupled electrochemical equations. This is done with the intention to reduce the overall number of subiterations necessary for resolving voltage, current density, and species concentration, properties of the fuel cell that are all directly coupled and require nested iterative approaches. The overall objective of this approach is an order of magnitude reduction in calculation time without sacrificing stability and increasing accuracy. Specific approaches involve using both bounded and unbounded techniques, such as the False Position method and the Secant method (or if applicable Newton-Raphson) respectively, the drawbacks being slower convergence for False Position and instability for the Secant or Newton-Raphson methods. Current preliminary results on simplified versions of the parent functions involved for electrochemical calculations indicate a reduction in computational steps by a factor of two for the secant method and a factor of three for Newton-Raphson. When implemented into new modified electrochemical algorithms, the results indicate a possible order of magnitude reduction in calculation time.
A method of manufacturing a proton-conducting fuel cell includes assembling a green anode-electrolyte half-cell by forming an anode substrate layer having an upper surface and a lower surface, forming an anode functional layer on the upper surface of the anode substrate layer, forming an electrolyte layer on an upper surface of the anode functional layer, and forming a stress balancing layer on the lower surface of the anode substrate layer. The method further includes positioning the green anode-electrolyte half-cell on kiln furniture inside a sintering kiln and sintering the green anode-electrolyte half-cell using SSRS to an anode-electrolyte half-cell.
High surface area carbon-supported platinum catalysts (Pt/HSC) are widely used in polymer electrolyte membrane fuel cells but often suffer from limited proton and oxygen transport within porous domains. To address these challenges, we integrate the ionic liquid [MTBD][beti] into Pt/HSC catalyst layers using two deposition methods-one-pot and sequential deposition-to tune IL distribution within micropores and mesopores. A combination of ex situ and in operando techniques were employed to elucidate electrode structure-performance relationships across a range of IL loadings. Sequential deposition achieved more efficient pore filling and higher IL retention at lower IL:C ratios, enabling enhanced proton conductivity and protection of active sites. Compared to the IL-free Pt/HSC, IL-modified electrodes demonstrated up to 28% improvement in mass activity and enhanced high-current-density performance under low relative humidity, while maintaining comparable performance under humidified conditions. Electrochemical impedance spectroscopy and CO displacement experiments reveal that improvements are linked to reduced ionic resistance and lower sulfonate adsorption on Pt sites, rather than changes in electrochemical surface area. However, excessive IL loading leads to mass transport losses. These results highlight the importance of selective pore filling and efficient IL distribution in achieving kinetic gains without compromising ionic and gas transport.