Christiaan Martinson (GRADUATED)



Characterisation of a proton exchange membrane electrolyser by electrochemical techniques

Characterisation tools are required to indicate the relationship between the performance and functional properties of the PEM electrolyser components.

The current switching method, also known as the current interrupt method, is conventionally used for estimation of the ohmic losses of an electrochemical system. The current switching method was implemented on other electrochemical cells like batteries and fuel cells. In this instance, the current switching method is used to indicate the electrochemical characteristics of the PEM electrolyser through an equivalent electric circuit. The electrochemical characteristics include the activation losses, ohmic losses and concentration losses.

The current switching method, consisting of the natural voltage response method and system identification, is used to develop the Randles-Warburg cell of the PEM electrolyser. The Randles-Warburg cell consists of the following components, the membrane resistance (Rm), the double layer capacitance (Cdbl), the charge transfer resistance (Rct) and the Warburg impedance (Zw). The membrane resistance relates to Ohmic losses, the charge transfer resistance relates to the activation losses and the Warburg impedance relates to the concentration losses.

Supervisors: Prof. George van Schoor, Dr. Kenny Uren and Dr. Dmitri Bessarabov