Solid Oxide Fuel Cell Technology Research Articles

Improvements of Micro-CHP SOFC System Operation by Efficient Dynamic Simulation Methods

Solid Oxide Fuel Cell (SOFC) technology is of high interest for stationary decentralized generation of electricity and heat in combined heat and power systems (CHP) for the residential sector. Application scenarios for SOFC systems in an electricity-regulated mode play an important role, especially in places where an electrical grid connection is not available or rather unstable. The advantages of SOFC systems are the high fuel flexibility and the high efficiencies also under partial load operation compared to other decentralized power generation technologies. Due to the long, energy-consuming system heat-up and the limited partial load capability, SOFC systems do not reach the performance of conventional power generation technologies. Furthermore, stack thermal cycling is associated with power degradation and should be minimized. In this paper, the improvement of these drawbacks are investigated for hotbox-based SOFC systems in the 1 kWel-class for residential applications. Since experimental investigations of the high-temperature systems are limited, modeling tools are established, enabling the visualization of internal system characteristics and providing the opportunity to simulate system operation in critical regions. To achieve this, a methodology for dynamic SOFC system modeling in a process engineering manner is developed based on the modeling language Modelica. A suitable approach is particularly important for modeling and simulation of the strong thermal interaction between the hot system components within the hotbox. The parametrized and validated models are used for the investigation of different dynamic effects, such as the system heat-up and the operation in low partial load points. A second reduced thermal system model aims for annual simulations of the SOFC system together with a battery to investigate the number of thermal cycles and the advantage of a hot standby operation. As a result, it is found that an adequate control of the power input at the start-up device and the cathode air flow has a high improvement potential to increase the stack heating rate and accelerate the heat-up in an energy-saving way. The hotbox-internal thermal management is identified as a crucial issue to reach low partial load points. To avoid the risk of stack cooling, lower heat losses and/or additional heat sources are of importance. Furthermore, the robustness of the tail gas oxidizer is found to be crucial for a higher load flexibility during partial load and the end of life stack operation. The annual simulation results indicate that operating the battery hybrid system with a hot standby mode requires much lower battery capacity for a high grid independence and a complete avoidance of system shutdown and associated power degradation.

Key CO2 capture technology of pure oxygen exhaust gas combustion for syngas-fueled high-temperature fuel cells

Integrated gasification fuel cells (IGFCs) integrating high-temperature solid oxide fuel cell technology with CO2 capture processes represents highly-efficient power systems with negligible CO2 emissions. Flame burning with pure oxygen is an ideal method for fuel cell exhaust gas treatment, and this report describes experimental and numerical studies regarding an oxy-combustor for treating the exhaust gas of a 10 kW IGFC system anode. The applied simulation method was verified based on experiments, and the key performance indices of the combustor were studied under various conditions. It was determined that 315 K was the ideal condensation temperature to obtain flame stability. Under these pure oxygen flame burning conditions, CO was almost completely converted, and the dry mole fraction of CO2 after burning was ≥ 0.958 when there was up to 5% excess O2. Overall, 5% excess O2 was recommended to maximize CO2 capture and promote other environmental considerations. Additionally, the optimal tangential fuel jet angle to control the liner temperature was approximately 25°. The total fuel utilization had to be high enough to maintain the oxygen flame temperature of the anode exhaust gas below 1800 K to ensure that the system was environmentally friendly. The results presented herein have great value for designing IGFCs coupled with CO2 capture systems.

Progress in Glass-Ceramic Seal for Solid Oxide Fuel Cell Technology

Solid oxide fuel cells (SOFCs) have emerged as promising energy conversion devices nowadays. SOFC consists of several components such as cathode, anode, electrolyte, interconnects, and sealing materials. In planar SOFC stack construction, the sealant and interconnection functions play an important role. Glass and ceramics are quite popularly used as SOFC sealing materials to achieve several functions including preventing leakage of fuel and oxidants in the stack and electrically isolating cells in the stack. In this review, material preparation, material composition, ceramic properties especially thermal properties are compared from various systems that have been developed previously. The main challenges and complexities in the functional part of SOFC sealants include: (i) chemical incompatibility and instability in the oxidizing and reducing environment by adjusting the value of the thermal expansion coefficient (CTE) with the interconnecting material during SOFC operation, and (ii) insulation of oxidizing fuels and gases by matching CTE anode and cathode. Also, the sealant glass transition determines the maximum permissible working temperature of the SOFC. The choice of method and analysis will provide data on various ceramic attributes. The search for thermal attributes consisting of Glass transition (Tg), Deformation temp (Td), Crystallization temp (Tx), Melting pt (Tm) became a focus on SOFC sealant development.

Criticality and Life-Cycle Assessment of Materials Used in Fuel-Cell and Hydrogen Technologies

The purpose of this paper is to obtain relevant data on materials that are the most commonly used in fuel-cell and hydrogen technologies. The focus is on polymer-electrolyte-membrane fuel cells, solid-oxide fuel cells, polymer-electrolyte-membrane water electrolysers and alkaline water electrolysers. An innovative, methodological approach was developed for a preliminary material assessment of the four technologies. This methodological approach leads to a more rapid identification of the most influential or critical materials that substantially increase the environmental impact of fuel-cell and hydrogen technologies. The approach also assisted in amassing the life-cycle inventories—the emphasis here is on the solid-oxide fuel-cell technology because it is still in its early development stage and thus has a deficient materials’ database—that were used in a life-cycle assessment for an in-depth material-criticality analysis. All the listed materials—that either are or could potentially be used in these technologies—were analysed to give important information for the fuel-cell and hydrogen industries, the recycling industry, the hydrogen economy, as well as policymakers. The main conclusion from the life-cycle assessment is that the polymer-electrolyte-membrane water electrolysers have the highest environmental impacts; lower impacts are seen in polymer-electrolyte-membrane fuel cells and solid-oxide fuel cells, while the lowest impacts are observed in alkaline water electrolysers. The results of the material assessment are presented together for all the considered materials, but also separately for each observed technology.

Prospects for cost-competitive integrated gasification fuel cell systems

Does generation of zero-carbon electricity from coal make sense for a decarbonized grid? Coal-based integrated gasification fuel cell systems with CO2 capture have the potential to participate in future decarbonized power grids. Over the next decade, such systems are scheduled to progress from a conceptual scheme to its first demonstration projects in China and Japan. A key issue in the long-term viability of the technology will be reducing costs so they are competitive against other forms of zero-carbon electricity; in addition, the systems must be able to operate as part of low carbon grids. We systematically evaluate the major on-going research directions, and rank them according to their economic potential, degree of technical challenge, and possible synergies with other efforts to transition to low-carbon energy systems worldwide. Our analysis indicates that the most promising pathway to making integrated gasification fuel cell technologies cost-competitive against other forms of low-carbon electricity is co-deployment of solid oxide fuel cell technologies in integrated gasification fuel cell cycle and distributed energy applications to expand the scale of production to a level that benefits both areas. Other avenues based on system optimization or improvements in fuel cell performance or degradation through materials development can help, but cannot by themselves deliver cost-competitive electricity absent an order of magnitude reduction in the cost of solid oxide fuel cell components.

Comparative techno-economic assessment of integrated PV-SOFC and PV-Battery hybrid system for natural gas processing plants

Natural gas will remain among the leading sources of energy, at least for the next few decades. Further, it is necessary to make natural gas processing operation a cost-competitive, clean, and efficient energy source, and less dependent on the grid. A comparative investigation based on two case studies is presented in this paper for a natural gas processing plant; an integration of Photovoltaic panels with Battery Energy Storage System (PV-BESS) and an integration of Photovoltaic panels with Solid Oxide Fuel cell (PV–SOFC) technologies. The aim is to be more independent from the grid for efficient operations and to reduce the emissions by introducing renewable energy in gas processing operation plant.A techno-economic analysis is performed for both cases considering a PV capacity of 33.5 MW. The outcome of this study indicates that for 25 years of operation, the Levelized cost of electricity (LCOE) for PV-BESS is found to be 0.16 US$/kWh, and for PV-SOFC is 0.11 US$/kWh, which makes the PV-SOFC option more economical and feasible than PV-BESS. Besides, in the projected scenario where investment cost is expected to reduce, PV-SOFC’s IRR is 3% and has a positive NPV of 5 Million USD$ for an internal rate of 4%. Furthermore, the LCOE for PV-SOFC in this scenario is around 0.04 USD$ per kWh, which is still less than the LCOE of PV-BESS and less than the tariff set by the Qatari electric authority for bulk industries.

SOFC Stack and System Modeling, Fault Diagnosis and Control

This report is an account of research and development activities undertaken by the Centre for Process Systems Computations, Department of Chemical Engineering at Curtin University, Western Australia in the area of solid oxide fuel cells. The focus of work of the group included 1)effect of cell macrostructure and microstructure on electrochemical performance with a view to optimise both macro- and micro-structure 2) electrochemistry modeling for simulating electrochemical performance 3) internal reforming aspects impacting performance at cell/stack and system levels 4) system level modeling investigating cell internal profiles (temperature, gas composition), homogeneity improvement, thermal management, anode recycle, fuel diversity, oxygen quality, and 5) monitoring for diagnostics, optimisation and control. The report summarizes work done over a period of 15 years and highlights areas of research gaps and future directions for research in the path to mass-scale commercialisation of the solid oxide fuel cell technology.

Development of nickel based cermet anode materials in solid oxide fuel cells – Now and future

High temperature solid oxide fuel cell (SOFC) is the most efficient and clean energy conversion technology to electrochemically convert the chemical energy of fuels such as hydrogen, natural gas and hydrocarbons to electricity, and also the most viable alternative to the traditional thermal power plants. However, the power output of a SOFC critically depends on the characteristics and performance of its key components: anode, electrolyte and cathode. Due to the highly reducing environment and strict requirements in electrical conductivity and catalytic activity, there are limited choices in the anode materials of SOFCs, particularly for operation in the intermediate temperature range of 500–800 ​°C. Among them, Ni-based cermets are the most common and popular anode materials of SOFCs. The objective of this paper is to review the development of Ni-based anode materials in SOFC from the viewpoints of materials microstructure, performance and industrial scalability associated with the fabrication and optimization processes. The latest advancement in nano-structure architecture, contaminant tolerance and interface optimization of Ni-based cermet anodes is presented. And at the end of this paper, we propose and appeal for the collaborative work of scientists from different disciplines that enable the inter-fusion research of fabrication, microanalysis and modelling, aiming at the challenges in the development of Ni-based cermet anodes for commercially viable intermediate temperature SOFC or IT-SOFC technologies.

Current Status of Solid Oxide Fuel Cell Technology Research and Development at National Energy Technology Laboratory

The DOE Office of Fossil Energy Solid Oxide Fuel Cell (SOFC) Program is interested in the near-term commercialization of high-temperature SOFC and solid oxide electrolyzer cell (SOEC) technologies that are robust, reliable, and resilient. A recent report delivered to the United States Congress highlighted several development recommendations including the design of pilot-scale units, continued early stage research and development, increased industrial engagement, and the exploration of reversible operation of SOFC technology.The National Energy Technology Laboratory (NETL) SOFC research group currently addresses most of these recommendations. NETL’s in-house research efforts focus on the characterization, simulation, and mitigation of high temperature degradation of fuel cell components. The capstone of these efforts is NETL’s SOFC degradation modeling framework, which uses NETL supercomputing facilities to simulate SOFC performance degradation of thousands of possible electrode configurations experiencing multiple simultaneous degradation modes under a broad array of relevant operating conditions. The models for the different degradation modes are based upon experimental data (1) generated in-house, (2) referenced from available scientific publications, and (3) shared from collaborations with other industrial, academic, and national laboratory partners within the SOFC Program. The team then employs techniques in data analytics to select optimal electrodes to maximize the SOFC performance for given operating conditions. These modeling efforts guide electrode engineering efforts in-house and through external collaborations by identifying (1) which degradation modes contribute the most to overall performance degradation for given operating conditions and (2) which electrode features will have the greatest impact on lowering cell degradation and system costs. Additionally, the development on non-invasive in situ high temperature fiber optic sensors for temperature and gas composition measurement provides valuable data for inclusion in degradation models as well as informing technology development at the commercial scale. Finally, the wealth of experience gained in development degradation models and materials for reducing the cost of SOFC technology is being readily applied to reducing the cost of SOEC technology.NETL will report on its most recent progress in the field of SOFC and SOEC development, including degradation modeling, in situ fiber optic sensor development, electrode engineering, and relevant systems-level analyses.

Comprehensive Evaluation of Manufacturing Costs and Environmental Impacts for Solid Oxide Electrolyzer Cell Systems

Fuel cells are attracting attention as a new energy device for the eco-friendly society. Solid oxide fuel cells (SOFCs) have high power generation efficiency and are developed for various fields (e.g. residential, commercial, distributed generation etc.). Recently, SOFCs are considered not only for power generation but also for electrolyzer cell (SOEC) systems. From the viewpoints of further development of fuel cells, a sustainable development is important perspective as well as their widespread use. Because SOFCs (or SOECs) must not only meet the required performance but also be viable in terms of cost and environment, we have conducted the cost evaluation for SOFCs [1, 2]. In this study, the comprehensive evaluation of SOECs was carried out with the method.An evaluation target is SOEC modules with various designs (i.e., planar type, flat-tubular type, tubular type, and metal-supported planar type). The manufacturing cost structure of these modules was estimated and compared with each other. In addition, hydrogen production cost by each module was calculated, and then the potential of the widespread use of SOFCs and SOECs was also discussed.The framework of this work is shown in Fig. 1. The feature of our method is that the database for each production process is built in. To change and/or add cell design and production process, this method provides flexibility and versatility. The result of the comprehensive evaluation for costs and environmental impacts was visualized by a cost structure (i.e., raw material, equipment, utility, labor, building etc.).In this method, the following steps were taken for each SOEC cell design. Firstly, the required specifications of the system were decided. The performance of SOEC and the required specifications for the cell were determined. Based on the results, the annual production of the module and components were determined. Secondly, for the production of SOEC modules with various designs, each production processes were designed by mass and energy balances. The facility cost and the footprint were also calculated. Finally, the manufacturing cost was calculated as the sum of fixed costs (construction cost, equipment cost) and variable costs (raw material cost, utility cost, labor cost). As the assessment of environmental impacts, CO2, NOx, SOx emitted during manufacturing, and materials, and industrial wastewater estimated from the production yield were evaluated.The evaluation of module manufacturing costs is described below. Under the conditions of annual production of 1000 units and the rated AC output power of 220 kW, the module manufacturing costs were calculated. Production costs for planar type, flat-tubular type, tubular type, and metal-supported planar type were 48.3, 51.8, 99.7, 38.8 JPY/W, respectively. It was found that the production cost of the metal-supported planar type was the lowest value due to the advantage of raw material costs. Thus, the comprehensive evaluation of SOECs is enabled with the method. Based on those results, we will discuss hydrogen production cost by SOECs as well as the environmental impacts via a module manufacturing.[1] J. Otomo, J. Oishi, T. Mitsumori, H. Iwasaki and K. Yamada, “Evaluation of Cost Reduction Potential for 1kW Class SOFC stack production: Implications for SOFC Technology Scenario” Int. J. Hydrogen Energy, 38 (33), 14337-14347, 2013.[2] J. Otomo, J. Oishi, K. Miyazaki, S. Okamura and K. Yamada, “Coupled Analysis of Performance and Costs of Segmented-In-Series Tubular Solid Oxide Fuel Cell for Combined Cycle System” Int. J. Hydrogen Energy, 42 (30), 19190-19203, 2017. Figure 1

Performance of a Natural Gas Solid Oxide Fuel Cell System With and Without Carbon Capture

Abstract The fuel cell program at the United States Department of Energy (DOE) National Energy Technology Laboratory (NETL) is focused on the development of low-cost, highly efficient, and reliable fossil-fuel-based solid oxide fuel cell (SOFC) power systems that can generate environmentally friendly electric power with at least 90% carbon capture. NETL’s SOFC technology development roadmap is aligned with near-term market opportunities in the distributed generation sector to validate and advance the technology while paving the way for utility-scale natural gas (NG)- and coal-derived synthesis gas-fueled applications via progressively larger system demonstrations. The present study represents a part of a series of system evaluations being carried out at NETL to aid in prioritizing technological advances along research pathways to the realization of utility-scale SOFC systems, a transformational goal of the fuel cell program. In particular, the system performance of utility-scale NG fuel cell (NGFC) systems with and without carbon dioxide (CO2) capture is presented. The NGFC system analyzed features an external auto-thermal reformer (ATR) feeding the fuel to the SOFC system consisting of planar anode-supported SOFC with separated anode and cathode off-gas streams. In systems with CO2 capture, an air separation unit (ASU) is used to provide the oxygen for the ATR and for the combustion of unutilized fuel in the SOFC anode exhaust along with a CO2 purification unit to provide a nearly pure CO2 stream suitable for transport for usage in enhanced oil recovery (EOR) operations or for storage in underground saline formations. Remaining thermal energy in the exhaust gases is recovered in a bottoming steam Rankine cycle while supplying any process heat requirements. A reduced order model (ROM) developed at the Pacific Northwest National Laboratory (PNNL) is used to predict the SOFC performance. The ROM, while being computationally effective for system studies, provides other detailed information about the state of the stack, such as the internal temperature gradient, generally not available from simple performance models often used to represent the SOFC. Such additional information can be important in system optimization studies to preclude operation under off-design conditions that can adversely impact overall system reliability. The NGFC system performance was analyzed by varying salient system parameters, including the percent of internal (to the SOFC module) NG reformation—ranging from 0 to 100%—fuel utilization, and current density. The impact of advances in underlying SOFC technology on electrical performance was also explored.

Crystal structures and proton transport properties of Sr2(Ti1-xMx)O4-δ (M = Fe, Al)

This study focuses on the effects of acceptor dopants in proton-conductive Sr2TiO4-based layered perovskites. We synthesized Sr2Ti0.9Fe0.1O4-δ (STF10) and Sr2Ti0.95Al0.05O4-δ (STA05) and evaluated the influence of ion substitution on their crystal structures, electrical conductivities, and proton transport properties. Our obtained results suggest that a redox reaction is the more favorable mechanism for the introduction of proton defects to Fe-doped samples compared with water vapor absorption, while the reverse is true for Al-doped samples. STF10 was found to exhibit a larger electrical conductivity at low temperatures than STA05. In addition, STF10 presented a proton transport number of 0.5 at 600 °C, while the corresponding value for STA05 was 0.5–0.6 at 450–600 °C. The higher proton transport number of STA05 at 450–550 °C compared to that of STF10 indicates that the Al-dopant suppressed the electronic conductivity owing to its constant valency. We therefore considered that characterization of the changes in material properties related to ion substitution can serve as a guide for material selection when developing proton-conducting solid oxide fuel cell technologies.

Development and application of a comprehensive model-based methodology for fault mitigation of fuel cell powered systems

The present paper describes an innovative and generalizable approach to apply fault mitigation strategies to fuel cell powered systems, upon information on system State of Health and Remaining Useful Life. Model-based approach is proposed to derive useful performance-related indicators for each system component. The model comprises two main parts: a nominal part, providing the key variables behavior in nominal conditions, and a faulty part that can be used for fault identification purposes. The framework of the algorithm firstly addresses a monitoring phase, through which residuals are computed, and if one or more residuals overcome defined thresholds, a fault detection is triggered. Afterwards, fault isolation is performed by means of a Fault Signature Matrix and the fault identification (i.e., its magnitude and time-behavior definition) is performed thanks to the faulty sub-models. Once characterized the fault, several strategies (according to different fault magnitudes) are considered, and the most suitable one can be chosen and applied. A case study is then presented to validate the methodology on a fuel starvation fault caused in a 6-cells solid oxide fuel cell stack by a fuel leakage in the anode pipeline. Once applied the mitigation strategy, it has been verified that the power output of the system safely bounds within 20% of its nominal value, whereas stack efficiency variation is negligible. The methodology herein proposed could substantially help the commercial success of solid oxide fuel cell technology, allowing increasing lifetime, with a much focused control of the main variable for diagnostic and maintenance-oriented applications. Indeed, if used in real applications, the proposed approach will speed up maintenance actions even setting the system in a soft condition to be properly prepared for replacement as well.

Infiltrated Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Based Electrodes as Anodes in Solid Oxide Electrolysis Cells

In the last decades, several works have been carried out on solid oxide fuel cell (SOFC) and solid oxide electrolysis cell (SOEC) technologies, as they are powerful and efficient devices for energy conversion and electrochemical storage. By increasing use of renewable sources, a discontinuous amount of electricity is indeed released, and reliable storage systems represent the key feature in such a future energy scenario. In this context, systems based on reversible solid oxide cells (rSOCs) are gaining increasing attention. An rSOC is an electrochemical device that can operate sequentially between discharging (SOFC mode) and charging (SOEC mode); then, it is essential the electrodes are able to guarantee high catalytic activity, both in oxidation and reduction conditions. Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) has been widely recognized as one of the most promising electrode catalysts for the oxygen reduction reaction (ORR) in SOFC technology because of its astonishing content of oxygen vacancies, even at room temperature. The purpose of this study is the development of BSCF to be used as anode material in electrolysis mode, maintaining enhanced energy and power density. Impregnation with a La0.8Sr0.2MnO3 (LSM) discrete nanolayer is applied to pursue structural stability, resulting in a long lifetime reliability. Impedance spectroscopy measurements under anodic overpotential conditions are run to test BSCF and LSM-BSCF activity as the electrode in oxidation mode. The observed results suggest that BSCF is a very promising candidate as an oxygen electrode in rSOC systems.

Momentum-species-heat-electrochemistry distribution characteristics within solid oxide fuel cell stack with complex inter-digital fuel channels

Obtaining the real working details within solid oxide fuel cell (SOFC) stacks are essential to the commercializing of SOFC technology. However, high operation temperature and small channel space features are two obstacles to achieving these details. In order to predict the complex physical item distribution characteristics within those SOFC stacks adopting inter-digital fuel channels, a comprehensive 5-cell large-scale model is firstly developed. The 3D model consists of all the complex solid, space, and porous medium components. After high-quality messes are addressed, the momentum, species, energy, e− and O2− charge conservation equations, and anodic/cathodic electrochemical reaction equations are coupled to the corresponding zones. The air/fuel flows, hydrogen/oxygen mole fractions, temperature, electrochemical active sites, and electric current distributing details within the stack are successfully achieved. It is an important step to further optimize the component structures for balancing the physics-chemical processes on stack level.

Development of solid oxide fuel cells using high-frequency plasma spraying technologies

The paper describes the topical issues and the latest achievements in the development of materials with high electrochemical characteristics for single cells and small assemblies of solid oxide fuel cells (SOFC). The authors propose planar SOFC technology which includes sequential deposition of all layers of a thin-film cell on a porous metallic substrate by plasma techniques. The method allows developing porous SOFC anode and cathode, which increases the active area of electrochemical reaction, reduces the spread of technological parameters (in particular, the spread in thickness and porosity of a solid electrolyte), improves SOFC performance and reduces the mass and size of SOFC assemblies. The paper also describes the physics of plasma spraying process in individual cells and SOFC structures. The proposed method is an alternative to traditional SOFC production methods; it eliminates the necessity to use agglomeration technology or other heat treatment. Moreover, it opens up the prospects for automated continuous production process. The appropriate SOFC production equipment is developed, for stationary and mobile use. Further studies will be focused on the task of reducing the weight of SOFC assemblies, which allows using them as an auxiliary power unit for on-board power supply, for example, for cars, airplanes and spaceships.

An efficient and durable perovskite electrocatalyst for oxygen reduction in solid oxide fuel cells

Achieving superior electrocatalytic activity and thermal/chemical stability of cathode materials is the key to high-performance and durable solid oxide fuel cells (SOFC). Here, we present a barium and praseodymium co-substituted perovskite Bi0.7Pr0.1Ba0.2FeO3-δ (BPBF), a cubic-symmetry oxide phase, as a candidate cathode material for SOFC, with a focus on its crystalline structure, oxygen transport, electrocatalytic activity, as well as structural and chemical stability. The BPBF-based cathode delivers superior electroactivity, with a polarization area-specific-resistance as low as 0.056 Ω cm2 at 700 °C in symmetrical cells. Surprisingly, when exposed to both air and 1 vol% CO2-containing air at 600 °C for 100 h, the electrode activity remains constant. The prominent thermal and chemical (CO2 tolerance) stability can be ascribed to co-substitution of barium and praseodymium and high acidity of bismuth ions. Endowed with favorable electrocatalytic activity and excellent durability, the BPBF-based material can be a promising cathode to facilitate commercialization of SOFC technology.

Solid oxide fuel cell technology paths: National innovation system contributions from Japan and the United States

This study discusses the solid oxide fuel cell (SOFC) technology paths in the United States and Japan under the national innovation system (NIS) framework using the available literature and a patent landscape. By examining technology trajectories, it is possible to identify and justify the patterns of key players and institutions from the NISs of the two countries that shaped the development of these technologies. These patterns are especially relevant to the analysis of the role of institutional arrangements in policymaking. This study presents the concept of a NIS and explores the main aspects of the Japanese and U.S. NISs regarding the SOFC technology path. This study analyzes historical patent evolution, patent applicants and their industrial sectors, international patent classifications (IPCs) and international patent activity. Moreover, this study highlights the correlations of the SOFC manufacturing and operation with patent data. This study examines the role of NISs in SOFC technology shaping from two main aspects: through independent historical events that motivated the establishment of institutional arrangements from which SOFCs have benefited and through shaping policies and efforts that are intended to promote the development of SOFC and related technologies. The results of this study demonstrate differences in terms of the sectors that are involved in the SOFC patenting activity, the IPCs of the filed patents and the international patent activity, which support the role of NISs in technology shaping.

Solid oxide fuel cell: Materials for anode, cathode and electrolyte

Solid oxide fuel cell technology is the technology which can be driving force to change the course of action of the modern era due to its optimal power generation features with maximum electrical efficiency for automobiles and household devices. Fuel cells can be best described as electrochemical devices that make use of fuel oxidation to convert chemical energy into electrical energy and also lower the amount of oxidant simultaneously.A typical SOFC consists of a cathode, anode and an electrolyte constituting a single cell. These single cells are stacked together for a bigger assembly to produce higher degree of power. The solid electrolyte fills the gap between the cathode and anode transporting O2− ions only. This leaves out electrons as transporting medium, which then pass through the cell via external circuit. Out of the two electrodes, oxidation of fuel takes place at the anode and reduction of oxygen takes place at the cathode. The SOFCs operate at higher temperatures of 600–1200°C producing heat as a byproduct of high quality, actively encouraging quick electrocatalysis utilizing non-precious metals and allowing internal restructuration. The SOFC can also work with high purity hydrogen for proton transport other than O2− ion transport. There are many ceramic materials which have been engineered to act as efficient electrolyte materials. Yttria-stabilized zirconia (YSZ) is the most widely used material as solid electrolyte in SOFC.The present review presents a detailed overview of the SOFC related materials and devices and is an effort to present various reported works in a concise manner.

Worldwide Status of Solid Oxide Fuel Cell Technology

The solid oxide fuel cell (SOFC) technology is expanding globally and finding new market opportunities in a variety of applications. The technology has not been fully tapped and has a promising future. The amazing versatility and applicability of the solid oxide (SO) technology is astounding as solid oxide fuel cells are developed as a source of efficient, low-cost electricity from natural gas distributed power generation, as reversible SO cells, and as solid oxide electrolyzers (SOEC) which have many applications in distributed generation (DG), hydrogen production, energy storage, microgrids, telecom backup market, combined heat and power (CHP), sensors, power to chemicals and fuels, data centers, ships, vehicles, absorption chillers, drones, and others. The United States has the greatest manufacturing capability and the most megawatts (MWs) of demonstrations of any nation due to Bloom Energy, which has over 350 MW of cumulative installation. The current US Department of Energy (DOE) Office of Fossil Energy SOFC Program administered by the National Energy Technology Laboratory (NETL) includes cell development and core technology research to increase the reliability, robustness, and durability of cell, stack, and system technology. Japan leads the world in the total number of demonstrations of the SOFC with over 60,000 kilowatt (kW)-class demonstrations by Kyocera. The European efforts of Ceres, SOLIDpower, Sunfire, Elcogen, and others represent major new directions into SO electrolysis, datacenters, and power-to-fuels. In the last decade China, through Suzhou Huatsing Power, SOFCMAN and CNFC, has made significant progress in SOFC and in electrolysis, scaling to 30-kWe and 80-kWe, respectively.