S. Giddey

Materials issues and recent developments in molten carbonate fuel cells

Molten carbonate fuel cell is one of the most promising high efficiency and sustainable power generation technologies, as demonstrated by the availability of several commercial units nowadays. Despite the significant progress made over the past few decades, the issues like component stability in carbonate melts and lower power density as compared to other high-temperature fuel cell systems need to be overcome to meet cost and lifetime targets. An improvement in the catalysts and system design for in situ reforming of fuel is critical to make molten carbonate fuel cells (MCFCs) compatible with real world fuels with minimal preprocessing requirements. Thus a significant opportunity exists for materials R&D in the MCFC area. In the present review, the key issues with MCFC component materials: cathode, anode, matrix, current collectors and bipolar plates, are discussed. The alternative materials and strategies adapted by the MCFC R&D community to mitigate these issues are discussed with emphasis on research trends and developments over the past decade.

Fuel Quality and Operational Issues for Polymer Electrolyte Membrane (PEM) Fuel Cells

Polymer electrolyte membrane (PEM) fuel cells are susceptible to degradation due to the catalyst poisoning caused by CO present in the fuel above certain limits. Although the amount of CO in the fuel may be within the permissible limit, the fuel composition (% CO2, CH4, CO and H2O) and the operating conditions of the cell (level of gas humidification, cell temperature and pressure) can be such that the equilibrium CO content inside the cell may exceed the permissible limit leading to a degradation of the fuel cell performance. In this study, 50 cm2 active area PEM fuel cells were operated at 55–60 °C for periods up to 250 hours to study the effect of methane, carbon dioxide and water in the hydrogen fuel mix on the cell performance (stability of voltage and power output). Furthermore, the stability of fuel cells was also studied during operation of cells in a cyclic dead end / flow through configuration, both with and without the presence of carbon dioxide in the hydrogen stream. The presence of methane up to 10% in the hydrogen stream showed a negligible degradation in the cell performance. The presence of carbon dioxide in the hydrogen stream even at 1–2% level was found to degrade the cell performance. However, this degradation was found to disappear by bleeding only about 0.2% oxygen into the fuel stream.

Yttria-doped ceria anode for carbon-fueled solid oxide fuel cell

Direct carbon fuel cells offer twice the efficiency compared with conventional coal-fired power plants and the highest efficiency among various fuel cells. However, the delivery of solid fuel to electrode/electrolyte interface is a critical issue and hinders the long-term performance of the fuel cell. The use of mixed ionic electronic conducting anodes has the potential to reduce the problem by shifting the fuel oxidation reaction from anode/electrolyte to anode/solid carbon interface. In search for a better anode material, Y2O3-doped ceria has been investigated as a suitable anode material for use in direct carbon fuel cells and the performance compared with Gd2O3-doped ceria. These materials have high ionic conductivity in oxidizing environments and are also known to have reasonable mixed ionic and electronic conductivity in reducing environments. In this manuscript, the stability of the anode materials in fuel cell operating environments has been investigated with X-ray diffraction (XRD) and scanning electron microscopy. Electrochemical impedance spectroscopy, in pure N2 and CO2/N2 anode chamber atmospheres, has been used to deconvolute the contribution of various fuel cell components to voltage losses and to elucidate the reaction mechanism. No precious metals were used on the anode side, neither as a catalyst nor as a current collector.

A versatile polymer electrolyte membrane fuel cell (3 kWe) facility

Abstract The polymer electrolyte membrane (PEM) fuel cell technology offers many advantages over other types of fuel cells in terms of high power density, low operating temperature and fast start, stop and load following capability. However, the stringent fuel quality requirements still remain a critical barrier for its commercialization. In this context, gaining knowledge on the effect of fuel compositions on the performance of the PEM fuel cells is essential to determine the fuel cleaning requirements for reformates from different fuel sources. In this paper, a test facility is described which has been established to study fuel quality issues, start, stop, thermal cycling and load following capabilities of PEM fuel cell stacks up to 3 kW e capacity. Important features of the test facility are described along with results of testing commercial and in-house built stacks up 1 kW e capacity.

Research and developments in hydrogen technologies

Abstract CSIRO has been involved in the research and development of fuel cell technology for a number of years. Initially the effort focused on solid oxide fuel cell technology, which led to a commercial activity, and now the polymer electrolyte membrane fuel cells including micro fuel cells for portable power applications are the focus of research and development. Other hydrogen and related technologies under development include solid state water electrolysis system for hydrogen generation and integration with sustainable energy sources, and hydrogen separation from byproducts of coal gasification or fossil fuel reformates. In this paper, a brief overview of these technology areas and progress made in CSIRO will be discussed.