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At least 739 records · Page 41

Membrane-electrode structures for molecular catalysts for use in fuel cells and other electrochemical devices

Water soluble catalysts, (M)meso-tetra(N-Methyl-4-Pyridyl)Porphinepentachloride (M=Fe, Co, Mn & Cu), have been incorporated into the polymer binder of oxygen reduction cathodes in membrane electrode assemblies used in PEM fuel cells and found to support encouragingly high current densities. The voltages achieved are low compared to commercial platinum catalysts but entirely consistent with the behavior observed in electroanalytical measurements of the homogeneous catalysts. A model of the dynamics of the electrode action has been developed and validated and this allows the MEA electrodes to be optimized for any chemistry that has been demonstrated in solution. It has been shown that improvements to the performance will come from modifications to the structure of the catalyst combined with optimization of the electrode structure and a well-founded pathway to practical non-platinum group metal catalysts exists.

30 DIRECT ENERGY CONVERSION↗

Energy Systems Integration Partnerships: NREL + GINER ELX

At current levels of renewable generation there are already periods when the supply of electrical power significantly exceeds the level of demand. The wide penetration of renewable energy sources (RES) requires an energy storage solution which can include hydrogen generated via Polymer Electrolyte Membrane (PEM) electrolysis.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Bipolar Membrane Development to Enable Regenerative FCs

We will develop bipolar membranes (BPMs) utilizing a dual-fiber electrospun junction/ interface for use in advanced and innovative reversible fuel cell (RFC) concepts. In fuel cell mode, the proton exchange membrane (PEM) and anion exchange membrane (AEM) transport protons and hydroxide ions produced at the electrodes to the PEM/AEM interface where water is generated.

30 DIRECT ENERGY CONVERSION↗

Proton conducting materials

The description includes materials that may be useful for fuel cell applications such as in the manufacture of fuel cell electrodes, proton exchange membranes (PEM), as catalyst additives or in tie layers designed to be thermally and chemically robust while operating within a fuel cell's harsh environment at higher temperatures and to conduct protons, with significantly higher levels of bound acidic groups, while in a low hydration state. Methods of making the materials are also described.

Hamrock, Steven Joseph↗

Packetized energy management control systems and methods of using the same

Aspects of the present disclosure include anonymous, asynchronous, and randomized control schemes for distributed energy resources (DERs). Such control schemes may include packetized energy management (PEM) control schemes for managing DERs that may provide near-optimal tracking performance under imperfect information and consumer quality of service (QoS) constraints.

Frolik, Jeffrey↗

In-Line Membrane Thickness Mapping with Real-Time Data Processing

The goal of this project is commercialization of a novel, patented by NREL, non-contact, in-line quality control thickness mapping tool that will enable 100% area inspection of multilayer polymer film assemblies, such as a PEM on a casting substrate, during continuous high-volume R2R manufacturing.

ENGINEERING,HYDROGEN↗

Market-Integrated Optimization of Wind-Battery-Hydrogen Hybrids for Peaking Capacity via Storage

As Integrated Energy Systems (IES) combine multiple energy and storage technologies to provide potentially more value and less risk via resource diversification, complementary overbuild, increased flexibility, and revenue-stacking, IES value is dependent on electricity market dispatch and grid interactions should play an important role in IES design and operation. This study hybridizes and retrofits wind and combustion turbine plants to study the impacts of replacing gas generation capacity with wind, battery, PEM electrolysis, hydrogen tanks and hydrogen turbines. The optimized design is co-simulated in a production cost model with different bidding strategies in order to compare performance and highlight the importance of grid-interactions. We analyze the revenue and dispatch changes as well as the price and cost implications of wind-battery-hydrogen IESs.

electrolysis↗

Carbon Corrosion in CO2 Electrolysis Systems

Driven by concerns over climate change, interest in CO2 conversion technologies has dramatically increased in recent years. By viewing CO2 as a readily available feedstock, many pathways for the production of carbon-neutral fuels and chemicals become available. In converting CO2, low carbon emitting energy sources must be used to ensure a low carbon footprint of the fuel and chemical products. The low-temperature electrochemical conversion of CO2 is a promising technology and allows for direct integration with renewable electricity sources. The development of low-temperature CO2 electrolysis technologies is informed by both PEM fuel cells and water electrolyzers, both of which are at a higher stage of development. However, CO2 electrolysis operates at a much higher cell voltage (-3V) than other low-temperature electrochemical processes, which can have implications for materials compatibility in the electrolyzer device. Carbon corrosion is of particular concern for the anode of CO2 electrolyzers, as a large driving force for corrosion exists due to the high required cell potentials. In this presentation, recent observations will be shared on carbon corrosion of the anode gas diffusion electrode (GDE) in low-temperature alkaline exchange membrane CO2 electrolysis. Results from ex-situ tests designed to isolate the carbon corrosion process for anode GDEs will be shared. These results will provide guidance on materials selection for CO2 utilization MEAs, which need to have a lifetime of several years to ensure industrial viability.

BIOMASS FUELS↗

Hydrogen Production, Grid Integration, and Scaling for the Future

The Hydrogen Production, Grid Integration, and Scaling for the Future project will inform clean hydrogen production deployment across the planning, procurement, and operation stages of hydrogen production on the grid. Hydrogen production from renewables is a clean source of fuel which is near zero for greenhouse gas emissions and criteria pollutants. The results from this project will inform entities looking to build clean energy projects that produce good paying jobs in manufacturing, installation, maintenance and operation of these facilities. This project provides system characterization examples, multiple configurations, optimizations, and suggested metering and custody transfer points through multiple scenarios and hardware testing of NREL's state-of-the-art 1.25 MW polymer electrolyte membrane (PEM) electrolyzer system to characterize system performance in relevant scenarios. This work also creates a digital twin for emulation in the Advanced Research on Integrated Systems (ARIES) virtual environment and performs hardware-in-the-loop (HIL) testing of pilot-scale, decentralized, and centralized hydrogen systems.

centralized hydrogen production↗

Electrolyzer and method of use

Disclosed are membrane electrode assemblies having a cathode layer comprising a carbon oxide reduction catalyst that promotes reduction of a carbon oxide; an anode layer comprising a catalyst that promotes oxidation of a water; a polymer electrolyte membrane (PEM) layer disposed between, and in contact with, the cathode layer and the anode layer; and a salt having a concentration of at least about 10 uM in at least a portion of the MEA.

Cave, Etosha R.↗

A Lattice Boltzmann Method for Predicting Porous Transport Layer Performance During Electrolysis

Electrolysis, the splitting of water into oxygen and hydrogen using electricity, is a sustainable way to produce green hydrogen for energy storage. In polymer electrolyte membrane (PEM) water electrolysis, water is brought into contact with charged catalyst layers and electrochemically separated into oxygen and hydrogen. The hydrogen product formed at the cathode is carried through the catalyst layer for eventual collection, while the oxygen by-product formed at the anode is removed from the surface via a multiphase interaction with circulating water and a solid porous transport layer (PTL). The design of this PTL aids in the detachment and advection of the oxygen by-product and thereby plays a role in the overall efficacy of the catalyst. In this presentation, we present our initial results modeling this multiphase system using a single-component, multiphase lattice Boltzmann method. We use the Shan-Chen model describing inter-particle forces to capture both the cohesion of the water (liquid) and oxygen (gas) phases and their interaction with the PTL (solid) (Shan and Chen, 1993). We use a Carnahan-Starling equation of state to model the effective density governing these inter-particle interactions which allows us to model this relatively high density ratio system (Carnahan and Starling, 1969). With these simulations, we show that the geometry and heterogeneity of the PTL geometry plays a large role in its ability to move oxygen away from the catalyst layer and the resulting bubble structures that are formed within the PTL. The current work demonstrates these effects using synthesized PTL geometries and 2D physics, which will be extended to experimentally-imaged PTL sections and 3D algorithms in the near future.

Boltzmann↗

Development of a new flux map processing code for moveable detector system in PWR

This paper presents an introduction to the development of the flux map processing code MAPLE developed by China Nuclear Power Technology Research Institute (CNPPJ), China Guangdong Nuclear Power Group (CGN). The method to get the three-dimensional 'measured' power distribution according to measurement signal has also been described. Three methods, namely, Weight Coefficient Method (WCM), Polynomial Expand Method (PEM) and Thin Plane Spline (TPS) method, have been applied to fit the deviation between measured and predicted results for two-dimensional radial plane. The measured flux map data of the LINGAO nuclear power plant (NPP) is processed using MAPLE as a test case to compare the effectiveness of the three methods, combined with a 3D neutronics code COCO. Assembly power distribution results show that MAPLE results are reasonable and satisfied. More verification and validation of the MAPLE code will be carried out in future. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

HydroGEN: Low Temperature Electrolysis

In low temperature electrolysis (LTE), it is imperative to both enhance and explore durability and demonstrate the opportunities for anion exchange membrane-based water electrolysis (AEMWE). The advantage of alkaline-based systems is primarily reduced capital cost: high pH enabling platinum group metal (PGM)-free catalysts and coatings, and the enhanced stability of those components compared to proton exchange membrane (PEM) -based systems. Compared to the water-only fed AEMWE in previous LTE 2.0 work, supporting electrolytes can allow for a significant improvement in performance through higher site-access and stability by reducing utilization and overpotential stresses that lead to catalyst layer delamination.

HYDROGEN↗

Hydrogen Production, Grid Integration, and Scaling for the Future

The project will explore near and long-term visions towards the commercialization of grid integrated electrolysis systems to inform deployment across the planning, procurement, and operation stages of hydrogen production on the grid. It will leverage NREL's state-of-the-art 1.25 MW polymer electrolyte membrane (PEM) electrolyzer system to characterize system performance in relevant scenarios, also creating a digital twin for emulation in the Advanced Research on Integrated Energy Systems (ARIES) virtual environment and performing hardware-in-the-loop (HIL) testing of pilot scale, decentralized, and centralized hydrogen systems.

electrolysis systems↗

HydroGEN: Low Temperature Electrolysis

In low temperature electrolysis (LTE), it is imperative to both enhance and explore durability and demonstrate the opportunities for anion exchange membrane-based water electrolysis (AEMWE). The advantage of alkaline-based systems is primarily reduced capital cost: high pH enabling platinum group metal (PGM)-free catalysts and coatings, and the enhanced stability of those components compared to proton exchange membrane (PEM) -based systems. Compared to the water-only fed AEMWE in previous LTE 2.0 work, supporting electrolytes can allow for a significant improvement in performance through higher site-access and stability by reducing utilization and overpotential stresses that lead to catalyst layer delamination.

HYDROGEN↗

A New Method for Creating Structured High-Performance Current Collectors for Electrochemical Applications

A significant challenge in many electrochemical systems is finding a stable, high-performing current collector material that is mechanically robust, adaptable in form factor, and free of precious metals. Titanium electrodes are robust in many of these regards but exhibit poor charge transfer performance due to self-passivation. Herein, a new materials processing paradigm based on the titanium/titanium nitride (Ti/TiN) system which allows for robust, stable, and low-resistance current collectors of arbitrary form factor is presented. Specifically, a gas-nitriding process for 3D-printed titanium electrodes that results in a 20-fold improvement of charge transfer characteristics relative to the untreated material is outlined. The ability to utilize 3D-structured current collectors with a net 40-fold improvement in performance over nonstructured electrodes is further demonstrated. This novel approach to creating electrochemical current collectors requires minimal laboratory resources and can be widely adapted for a variety of applications, including desalination, electrolysis, energy storage, and basic research. In conclusion, the work described herein provides both a means for accelerating research and opens the door to hierarchical tuneability for enhanced performance.

36 MATERIALS SCIENCE↗

The Impact of Catalyst Layer Composition and Structure on Performance and Durability of PEMWE Anodes

A study of various compositions of anodes for proton exchange membrane water electrolysis aimed at reducing precious metal content and system costs without compromising performance and durability is presented. A key challenge in current water electrolysis technologies is the reliance on high iridium loadings to ensure sufficient catalytic activity, electronic conductivity, and durability for the oxygen evolution reaction. To address this, catalyst layers based on the stable but kinetically limited rutile phase of iridium oxide are combined with platinum nanoparticles and carbon-based additives to improve structural properties and ink processability. By systematically varying the volume ratios of carbon to precious metals and ionomer to solids, compositional trends have been identified, and significant performance improvements have been achieved. Structural and elemental analysis confirms improved dispersion of platinum and iridium can be achieved, as well as electronic conductivity improvements within the catalyst layer. Polarization curve analysis has shown the ability of added Pt and C to significantly increase catalytic activity. These results highlight the potential positive impact of Pt and C on anode structure, composition, and cell performance.

36 MATERIALS SCIENCE↗

Exploring the Interface of Skin-Layered Titanium Fibers for Electrochemical Water Splitting

Water electrolysis is the key to a decarbonized energy system, as it enables the conversion and storage of renewably generated intermittent electricity in the form of hydrogen. However, reliability challenges arising from titanium-based porous transport layers (PTLs) have hitherto restricted the deployment of next-generation water-splitting devices. Here, it is shown for the first time how PTLs can be adapted so that their interface remains well protected and resistant to corrosion across ˜4000 h under real electrolysis conditions. It is also demonstrated that the malfunctioning of unprotected PTLs is a result triggered by additional fatal degradation mechanisms over the anodic catalyst layer beyond the impacts expected from iridium oxide stability. Now, superior durability and efficiency in water electrolyzers can be achieved over extended periods of operation with less-expensive PTLs with proper protection, which can be explained by the detailed reconstruction of the interface between the different elements, materials, layers, and components presented in this work.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗