Eiji Endoh

Degradation study of MEA for PEMFCs under low humidity conditions

The degradation study of the membrane electrode assembly (MEA) for proton exchange membrane fuel cells (PEMFCs) under low humidity conditions was conducted. The MEA degradation was observed during low humidity open-circuit voltage tests. To investigate the degradation mechanism, we conducted electron spin resonance studies of the degenerated MEA, and confirmed the formation of radicals in the catalyst layers. The MEA degradation mechanism that includes the radical formation reaction was verified.

New Raney nickel composite-coated electrode for hydrogen evolution

Abstract New Raney nickel coated electrodes have been developed for hydrogen evolution cathodes in alkaline media. The electrodes are made by a composite-coating technique from a nickel plating bath in which pulverized Raney nickel alloy is uniformly dispersed. The results of many tests under different conditions are reported. The electrodes exhibit low hydrogen overvoltages (80–100mV at 90°C, at 200–400mA cm−2 in 35wt% NaOH and 60–80mV at 200mA cm−2 at 90°C in a cell liquor) and excellent stability under different operating conditions.

Advanced low hydrogen overvoltage cathode for chlor-alkali electrolysis cells

Abstract An advanced low hydrogen overvoltage cathode has been developed for use in chlor-alkali electrolysis cells. The cathode is made by composite-coating a novel ternary Raney nickel electrocatalyst on a variety of substrates. The results of many performance tests in laboratory cells as well as commercial cells are reported. The cathode exhibits a low hydrogen overvoltage (50–70 mV at 90°C, at 30 A dm −2 in a 35 wt% NaOH), excellent stability under cell short-circuiting conditions and a considerably long cathode life, up to the present four years in commercial plants. The excellent stability of the cathode against cell shutdown conditions has been discussed.

Development of highly durable low hydrogen overvoltage cathode in chlor-alkali cells

A novel cathode with a metal hydride and a Raney nickel electrocatalyst has been developed for highly durable low hydrogen overvoltage cathodes in chlor-alkali electrolysis cells. The cathode is made by composite-coating a Raney nickel alloy and a metal hydride on a cathode substrate. The cathode exhibits a low hydrogen overvoltage (ca 80 mV at 90°C, at 30 A dm 2in a 35 wt% NaOH), and has excellent stability under cell short-circuiting shutdowns as well as under normal operating conditions. The mechanism of the excellent stability under shutdown conditions has been discussed.

Improvement of Membrane and Membrane Electrode Assembly Durability

The worlds first highly durable perfluorinated polymer-based membrane electrode assembly (MEA) for polymer electrolyte membrane fuel cells, under conditions of high temperature and low humidity, has been developed. The newly developed MEA, which is composed of a new perfluorinated polymer composite membrane, reduces the degradation rate to 1/100th to 1/1,000th of that of the conventional MEA. The new perfluorinated polymer composite MEA can be operated for more than 6,000 h at 120°C and 50% relative humidity.