In-situ measurement of hydrogen crossover in polymer electrolyte membrane water electrolysis

An in-situ method for determination of hydrogen crossover in polymer electrolyte membrane (PEM) water electrolysis cells is discussed. The measurement principle is based on the electrochemical compensation of the crossover flux, which translates the mass flux determination into an electric current measurement. The proposed method features an extremely simple set-up and measurement procedure, as well as high accuracy. It allows for measurement with a fully assembled cell at normal water electrolysis conditions by use of standard equipment, also installed in industrial electrolyzer plants. The technique is especially suitable for high-pressure PEM electrolyzers operated under asymmetric pressure conditions. The applicability of the suggested method for a broad pressure range is briefly illustrated with a laboratory scale electrolyzer plant and by comparison of the measured data with available literature values.