Akiyoshi Manabe

Study of Alkaline Water Electrolysis

Chlorine Engineers Corp., Ltd. (CEC) is special electrochemical company in Japan and was established in 1973, when mercury process of chlor-alkali industry was abandoned by Japanese government. Since then, CEC has accumulated electrolysis technology and has an interest for future hydrogen society. In the background, zero gap system was applied for cell evaluation of alkali water electrolysis based on CEC’s technology. A special electric collector for cathode was used to create zero gap without damaging the separator. Cell voltage was 1.76V at 40A/dm 2 , 80 deg.C. Raney Ni alloy coating had advantage for oxygen overvoltage. (100mV – 200mV saving against Ni metal) Thermal decomposition coating of cathode showed low hydrogen overvoltage (around 100mV). Ion exchange membranes N117 and F8020 showed high cell voltage (over 2.2V) but high purity of H2 gas (over 99.95%). Porous polyolefin film showed low cell voltage but had less durability.