Durable polymer electrolyte fuel cells (PEFC) for residential co-generation application

Abstract

The fuel cell researches using the molten salts, oxides, and others as electrolytes were conducted in the early 20th century. In 1921, the high-temperature fuel cell of 1.5 kW was demonstrated using molten carbonate as the electrolyte.The basic configuration of the current fuel cell in which the porous structures of the cathode and anode are sandwiched between electrolytes was established in 1933 in the Bacon cell that used alkaline water solution as the electrolyte and nickel sintered compact as the electrode. The Bacon cell was significant in presenting a practical fuel cell configuration where the efficient electrode reactions were obtained at the Introduction (Background of research)The fuel cell power generation, in which the energy generated in the production of water in the electrochemical reaction of hydrogen and oxygen is used as electricity, is a technology where the chemical energy of a substance is directly converted into electric energy. It is not limited by the Carnot efficiency because it does not involve heat energy as in the heat engine, and high energy conversion efficency can be expected. Therefore, many researches have been conducted for its practical application. Since the fuel cell converts the energy of the chemical reaction between hydrogen and oxygen to electricity, the reaction progresses faster at higher reaction temperature, and this enables improvement in efficiency. Since the produced emission is water, it is clean and is highly environment friendly.The fuel cell started from the gas reaction experiment conducted by Sir William Robert Grove of Britain in 1839. As shown in Fig. 1, this experiment probably involved two platinum electrodes in dilute sulfuric acid solutions, where one electrode was filled with hydrogen gas and the other with oxygen gas. The electrodes were connected in series, and electrolysis was conducted by the generated electricity. The power generation using the electrochemical process did not advance far compared to the dramatic leap of the generation using the heat engines. However, the basic researches for the high-temperature fuel cell were conducted as one application of this technology to the generation method using coals combustion technology, the major fuel course of that time. -Elucidation of degradation mechanism to establish an accelerated aging test method of PEFC-Co-generation system using clean and compact PEFC which makes highly efficient power generation possible, promotes considerable energy savings at home since it provides both heat and electricity together. Therefore, its commercialization has been expected. The goal of 40000-hour-operation has been set as a practical target. In order to realize it, the durability of PEFC has been technologically prospected and the accelerated aging test protocol of PEFC has been developed within the frame of the consortium of PEFC makers, energy companies, academia and AIST. AIST has shown the rationality of the accelerated aging test protocol of PEFC through the experimental verification of hypothetical degrad...