Solid State Energy Conversion Alliance Research Articles

(Invited) Descriptors, Defects, and DFT for Solid Oxide Fuel Cell Materials

Active oxygen materials that can rapidly transport and exchange oxygen with the environment play a critical role in many existing and developing technologies, e.g., solid oxide fuel cells (SOFCs), gas separation membranes, oxygen sensors, chemical looping devices, and memristors. In particular, reducing the working temperature of SOFCs, which is critical to their increased commercialization, is significantly inhibited by the slow oxygen reduction reaction at the cathode. The steps in the ORR and related oxygen transport are complex enough that it still remains an open challenge how to design improved cathode catalytic activities using either intuition or computational materials design tools. In this presentation we summarize our recent results on using the Oxygen 2p-band (or just “p-band”) as a descriptor for many important properties related to SOFC cathode performance for both perovskite and 214 Ruddlesden-Popper oxides. We demonstrate that the p-band, which is an easy to calculate bulk electronic structure descriptor, correlates with properties that include oxygen vacancy and interstitial defect energies [1, 2], oxygen diffusion coefficients [3, 4], surface exchange coefficients [1, 3], and cathode area specific resistance [1] (e.g., see Figure 1). This descriptor is therefore a powerful tool for active oxide materials design, and we describe its use to search for promising new SOFC cathode materials. The p-band descriptor highlights some of the intriguing differences in trends of defect chemistry and surface exchange behavior between the perovskite and 214 Ruddlesden-Popper phases. Specifically, the dominance of vacancy and interstitial defects, respectfully, in the oxygen exchange and transport in these two classes of materials leads to opposite trends in their behavior with p-band and generally in the behavior with oxygen bond strength and state of oxidation. We show the results of detailed calculations of the defect behavior in 214 Ruddlesden-Popper La2-xSrxMO4+d (M = Co, Ni, Cu) compounds and demonstrate how the crossover in dominant defects with doping can be understood in terms of simple trends in oxidation chemistry. We further demonstrate that the previously identified but somewhat elusive peroxide defects are stable in Ruddlesden-Popper phases over some doping domains and can play a role in the oxygen transport in these materials. Acknowledgement We gratefully acknowledge financial support from the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award number DE-SC0001284, Department of Energy (DOE), National Energy Technology Laboratory (NETL), Solid State Energy Conversion Alliance (SECA) Core Technology Program (Funding Opportunity Number DEFE0009435), and the National Science Foundation Software Infrastructure for Sustained Innovation (SI2) (award no. 1148011). Computing in this work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by U.S. National Science Foundation with grant number ACI-1053575, and the National Energy Research Scientific Computing Center (NERSC) allocation of the CNMS at ORNL (CNMS2013-292).

Accomplishments, Status, and Road Map for the US Department of Energy's Fossil Energy SOFC Program

The U.S. Department of Energy Office of Fossil Energy is charged with developing ultraclean (near-zero emissions), low-cost energy from fossil fuels to fuel economic prosperity, strengthen energy independence, and enhance environmental quality. A component of that effort, implemented by the National Energy Technology Laboratory, is the Solid State Energy Conversion Alliance, which is developing low-cost, highly efficient solid oxide fuel cell power systems that produce electric power from natural gas or coal with intrinsic carbon capture capabilities. In coordinated work involving industry, academia, and national laboratories, progress is being made in areas critical to technology commercialization, including seals, cells power density and stability, and low-cost interconnects. Cell tests have yielded acceptable performance and degradation rates. The program is now focusing on improving stack and system performance, reliability, and durability through progressively larger stack tests and integrated systems tests. Accomplishments, current program status, and the roadmap for continuing work are reviewed.

SECA Program Overview and Status

The overall objective of the Solid State Energy Conversion Alliance (SECA), a U.S. Department of Energy program coordinated and managed by the National Energy Technology Laboratory, is the development of advanced power generation system technology. Specifically, the systems being developed, for central-station (>100 MWe) application, and based on solid oxide fuel cell (SOFC) technology, are to be cost-effective and operate with high electric efficiency. Further, their designs must provide for effective carbon (CO2) capture, and they must restrict the emission of other pollutants (eg, Hg, NOx, SOx) and conserve water. Historically, the fuel basis for this development has been coal, our major domestic energy source. This continues to be the focus. However, the program is cognizant that the SOFC technology developed to meet design objectives could be adapted for implementation in advanced power generation systems fueled with natural gas. Thus, there could be strong synergy between efforts to develop advanced coal-fueled power generation, as in the SECA program, and any parallel effort by the program participants to develop natural gas-fueled distributed-generation SOFC power systems. A natural gas-fueled distributed power generation system could be first to the marketplace, which would provide early manufacturing and operational experience on large commercial scale that would benefit SOFC power system developments with both fuels. SECA program status is reviewed.

Solid Oxide Fuel Cell Stack Module Development for Fuel Flexible Power Generation

FuelCell Energy is developing solid oxide fuel cell (SOFC) systems and technology for very efficient, economically viable, coal-to-electricity power plants utilizing synthesis gas (syngas) from a coal gasifier for the Department of Energy Solid State Energy Conversion Alliance (SECA) program. SOFC technology development includes cell performance enhancement, stack building block scale-up, stack tower design and testing, and development of a 250 kW module accommodating multiple stack towers.

Role of solid oxidefuel cells in a balanced energy strategy

The 2012 Department of Energy (DOE) budget request significantly reduces fuel cell RD&D funding and would cease to support the Solid State Energy Conversion Alliance (SECA), DOE's solid oxide fuel cell (SOFC) program. This would be a grave mistake considering the US's historic dominance in fuel cell RD&D, exciting recent technological advancements in fuel cells, and clear positive market signals around the globe. In this paper we discuss DOE's energy RD&D policy, how SOFCs address every key DOE strategy, and why recent advances should make SOFCs an integral part of our energy RD&D policy. Moreover, we compare the prospects of low temperature SOFCs with the more common proton exchange membrane fuel cell (PEMFC) in the absence of a hydrogen infrastructure.

Development of Solid Oxide Fuel Cells at Versa Power Systems

Versa Power Systems (VPS) is a developer of solid oxide fuel cells (SOFCs) for clean power generation. VPS has been working with its development partner FuelCell Energy within the U.S. Department of Energy (DOE) Office of Fossil Energy's Solid State Energy Conversion Alliance (SECA) program to apply SOFC technology in large-scale power plant systems. As a result, initiatives such as scale-up of the cell and stack are being actively pursued for these applications.

Recent Developments in the SECA Program

The development of an electric power generation technology that effectively uses coal, our major domestic energy source, and meets environmental requirements and water conservation needs, is of crucial importance to the United States. Work to achieve that objective is being done by the U.S. Department of Energy Office of Fossil Energy. Embodied in the Solid State Energy Conversion Alliance (SECA) program, the development of the required power generation technology is centered on the solid oxide fuel cell as the key enabling technology, and is being done at the National Energy Technology Laboratory. The overall SECA program goal is the development of power generation technology for cost-effective, high-efficiency, central-station (>100 MWe) power systems that are equipped for effective carbon capture, and which restrict to specified levels the emission of other pollutants such as mercury, NOx, and SOx. SECA program status and accomplishments are reviewed.

The Status of SOFC Programs in USA 2009

The U.S. Department of Energy's (DOE) Office of Fossil Energy's (FE) National Energy Technology Laboratory (NETL), in partnership with private industry, educational institutions and national laboratories, is leading the research, development, and demonstration of high efficiency, fuel flexible solid oxide fuel cells (SOFCs) and coal-based SOFC power generation systems for stationary market large central power plants. The FE Fuel Cell Program has three parts under the Solid State Energy Conversion Alliance (SECA): cost reduction, coal-based systems, and research and development. The SECA cost reduction goal is to have SOFC stacks capable of being manufactured at $170 per kilowatt (2007 basis) by 2010. Concurrently, the scale-up, aggregation, and integration of the technology will progress in parallel leading to prototype validation of megawatt (MW)-class fuel flexible products by 2012 and 2015. The SECA coal-based systems goal is the development of large (greater than 100 MW) integrated gasification fuel cell (IGFC) power systems.

The Status of SOFC Development at Versa Power Systems

Versa Power Systems (VPS) is a developer of solid oxide fuel cells (SOFCs) for clean power generation. VPS has been working with its development partner FuelCell Energy within the U.S. Department of Energy (DOE) Office of Fossil Energy's Solid State Energy Conversion Alliance (SECA) program to apply SOFC technology in large-scale, multi-megawatt power plant systems that utilize coal in a clean and efficient manner. As a result, new initiatives such as scale-up of the cell and stack are now being actively pursued for these applications.

U.S. Department of Energy's SECA Program: 2008 Progress and Plans

The U.S. Department of Energy's (DOE) Office of Fossil Energy's (FE) National Energy Technology Laboratory (NETL), in partnership with private industry, educational institutions and national laboratories, is leading the research, development, and demonstration of high efficiency, fuel flexible solid oxide fuel cells (SOFCs) and coal-based SOFC power generation systems for stationary market large central power plants. The FE Fuel Cell Program has three parts under the Solid State Energy Conversion Alliance (SECA): cost reduction, coal-based systems, and research and development. The SECA cost reduction goal is to have SOFCs capable of being manufactured at $400 per kilowatt (kW) by 2010. Concurrently, the scale-up, aggregation, and integration of the technology will progress in parallel leading to prototype validation of megawatt (MW)-class fuel flexible products by 2012. The SECA coal-based systems goal is the development of large (greater than 100 MW) integrated gasification fuel cell (IGFC) power systems.

Development of Solid Oxide Fuel Cells at Versa Power Systems

Versa Power Systems (VPS) is a developer of solid oxide fuel cells (SOFCs) for clean power generation. VPS has been working with its development partner FuelCell Energy within the U.S. Department of Energy (DOE) Office of Fossil Energy's Solid State Energy Conversion Alliance (SECA) program to apply SOFC technology in large-scale, multi-megawatt power plant systems that utilize coal in a clean and efficient manner. As a result, new initiatives such as widening the temperature of operation (600-800{degree sign}C) and scale-up of the cell and stack are now being actively pursued for these applications.

U.S. DOE Fossil Energy Fuel Cell Program

The U.S. Department of Energy's Office of Fossil Energy's National Energy Technology Laboratory, in partnership with private industry, educational institutions, and national laboratories, is leading the research, development, and demonstration of high efficiency, fuel flexible solid oxide fuel cells (SOFCs) and coalbased SOFC power generation systems for stationary markets. This Fuel Cell Program has three parts: Solid State Energy Conversion Alliance (SECA) cost reduction, SECA fuel cell coalbased systems, and advanced SECA systems. The SECA cost reduction goal is to have SOFCs capable of being mass manufactured at $400 per kilowatt by 2010. Concurrently, the scale-up, aggregation, and integration of the technology will progress in parallel leading to prototype validation of megawattclass products by 2012 with potential testing at FutureGen. The SECA coal-based and advanced systems goals are the development of megawatt-class fuel cell power systems that will enable affordable, reliable, efficient, and environmentally-friendly electrical power from coal.

GE SECA Prototype System Development and Testing

This paper summarizes the prototype system development and testing under Solid State Energy Conversion Alliance (SECA) Solid Oxide Fuel Cell Program. There were two generations of the SECA prototype systems developed. The Gen 1 prototype system met or exceeded the SECA requirements over a 1720h test, achieving 41% peak system efficiency and 5.4 kW peak net power. The Gen 2 prototype achieved 49.6% peak efficiency and 5.6 kW peak net power over a 120h commissioning test. The Gen 2 prototype system has been delivered to National Energy Technology Laboratory (NETL) for final testing.

Solid Oxide Fuel Cell Development: Latest Results

Delphi is developing Solid Oxide Fuel Cell (SOFC) technology for applications in a variety of markets (1-5). This paper outlines the development of SOFC stack by the Delphi Battelle team under the US Department of Energy's Solid State Energy Conversion Alliance (SECA) program. Delphi successfully completed Phase 1 of this program and met the key technical and cost targets. This paper outlines key achievements in stack development by the Delphi Battelle team in moving forward towards meeting the goals for commercialization.

Coal Without Combustion

This article focuses on various researches that have been undertaken to study and test use of fuel cells instead of boilers for cheap and clean electricity production. One of the most ambitious projects is the Solid State Energy Conversion Alliance (SECA), created by the U.S. Department of Energy to clear the technical hurdles that have kept fuel cells impractical. Compared to other government research programs, SECA has an unusual structure. The program unifies several organizations to work toward a common goal, yet retains a healthy spirit of competition to drive progress and spur innovation. By developing fuel cells to operate efficiently and cost effectively on the fuels that dominate today’s power industry, the hope is that the program can help meet pressing environmental and energy-security needs while building a bridge to a low-carbon economy. SECA’s recent successes demonstrate that it’s only a matter of time before solid oxide fuel cell technology achieves its commercial potential. Indeed, it’s possible that Solid Oxide Fuel Cells could reach high enough standards of efficiency and economy to entirely replace conventional combustion as the primary means of generating electricity in the USA.

Solid Oxide Fuel Cells: Fundamentals to Systems

AbstractThe U.S. Department of Energy (DOE) Office of Fossil Energy's (FE) National Energy Technology Laboratory (NETL), in partnership with private industry, educational institutions and national laboratories, is leading the development and demonstration of high efficiency solid oxide fuel cells (SOFCs) and fuel cell‐turbine (FCT) hybrid power generation systems for distributed generation (DG) markets. The DOE FE DG program has three aspects: the Solid State Energy Conversion Alliance (SECA), Fuel Cell Coal Based Systems for central power, and the High Temperature Electrochemistry Center (HiTEC). NETL is partnering with Pacific Northwest National Laboratory (PNNL) in developing new directions in research under SECA for the development and commercialization of modular, low cost, and fuel flexible SOFC systems. The SECA initiative, through advanced materials, processing, and system integration research and development (R&D), will bring SOFC system cost to $400 per kilowatt (kW) by 2010 for stationary and auxiliary power unit (APU) markets. The SECA program is currently structured to include six competing industry teams supported by a crosscutting core technology program (CTP). DOE is ultimately concerned with coal‐based central power plants. Advanced aspects of solid oxide technology are part of HiTEC R&D.

Distributed generation—Molten carbonate fuel cells

High efficiency and ultra-clean molten carbonate fuel cell (MCFC) technology development by FuelCell Energy, with support from the U.S. Department of Energy (DOE), has progressed to commercial power plants for stationary applications such as distributed generation. Lessons learned from this development will also be valuable to DOE for the ongoing Solid State Energy Conversion Alliance (SECA) solid oxide fuel cell (SOFC) development and cost reduction, for fuel cell turbine hybrids, and for hydrogen economy development with FutureGen.

Solid oxide fuel cell technology development in the U.S.

The U.S. Department of Energy (DOE) Office of Fossil Energy (FE) through the National Energy Technology Laboratory (NETL) is leading the development and demonstration of high efficiency and low cost solid oxide fuel cells (SOFCs) and fuel cell turbine (FCT) hybrid power generation systems primarily under the Solid State Energy Conversion Alliance (SECA). Additional long-term basic research is performed at the High Temperature Electrochemistry Center (HiTEC). Distributed generation (DG) systems have ultra low emissions, produce water, and can be configured to isolate/segregate carbon dioxide – all features useable in FutureGen and advanced coal-based systems.

U.S. DOE fossil energy fuel cells program

The U.S. Department of Energy's (DOE) Office of Fossil Energy's (FE) National Energy Technology Laboratory (NETL), in partnership with private industry, educational institutions and national laboratories, is leading the development and demonstration of high efficiency, high temperature solid oxide fuel cells (SOFCs) and fuel cell turbine (FCT) hybrid power generation systems for stationary markets including auxiliary power units (APUs), distributed generation (DG) and large, coal-based central power plants. The DOE FE fuel cells program has three aspects: the Solid State Energy Conversion Alliance (SECA), Fuel Cell Coal Based Systems for central power, and the High Temperature Electrochemistry Center (HiTEC). The SECA goal is to decrease SOFC system cost to US$ 400 per kilowatt (kW) by 2010 for stationary markets. DOE FE is ultimately concerned with coal-based central power plants such as FutureGen. The goal is to aggregate SECA-type fuel cells into larger systems and to produce a very high efficiency megawatt-class FCT hybrid for testing at FutureGen. The low-cost, US$ 400 kW −1 SECA FCT hybrid is a key component to achieving 60% efficiency by 2020. Advanced aspects of solid oxide technology are part of HiTEC R&D. Technical progress and advances are discussed for all three program aspects.

U.S. Department of Energy′s Solid Oxide Fuel Cells: Technical Advances

AbstractFor Abstract see ChemInform Abstract in Full Text.