Challenging of Reducing Electrolysis Voltage by Superimposing Boiling on PEMWE–A Thermodynamic Coupling–

Abstract

This study challenges to decrease water electrolysis voltage by thermodynamic coupling between boiling and water electrolysis. Boiling, once a system to cause boiling is given, spontaneously advances and causes entropy generation. When boiling is superimposed on an electrode where electrochemical reaction of water electrolysis progress, the entropy generation by the boiling possibly accelerates the reaction of water electrolysis, leading to reduction of electrolysis voltage. To confirm this new concept, electrolysis voltage for a unit cell of PEMWE is measured in the region from 80°C to 120°C under a condition that cell pressure and electrolysis current are kept constant. The measurement results showed that the electrolysis voltage abruptly decrease as cell temperature crosses boiling point and then turn to increase at a few degree higher than the point. These features in the measurement were reproduced in the theoretical analysis based on a mathematical model considering the thermodynamic coupling.