Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5145568 | International Journal of Hydrogen Energy | 2017 | 12 Pages |
Abstract
Hydrogen permeation is an important phenomena for PEM water electrolyzers, due to several reasons as safety issues and efficiency loss. The present contribution deals with the measurement of hydrogen volume fraction within the anode product gas during PEM water electrolysis for different temperatures and cathode pressures. High cathode pressures lead to high anode hydrogen volume fractions close to the lower explosion limit of hydrogen in oxygen, which are caused by increased hydrogen permeation. It is shown that the results of the hydrogen volume fraction measurements can be easily converted into hydrogen permeation rates. Additionally, the experimental obtained permeation data indicate that hydrogen permeation increases linear with increasing current density. The impact of current density on the hydrogen permeation is very strong in comparison to the effects of temperature and pressure e.g. a current density increase of 1Â A/cm2 can causes a permeation increase comparable to a cathode pressure increase of 20Â bar. In the second part of this contribution different theories to explain this strong dependence on current density are discussed. The most probable explanation is that due to mass transfer limitations a supersaturation of dissolved gas within the catalyst ionomer film arises that causes the investigated increase in permeation.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
P. Trinke, B. Bensmann, R. Hanke-Rauschenbach,