Electrolysis: SIVONIC

Electrochemical impedance spectroscopy (EIS) is a state-of-the-art method for precisely analyzing the electrical and electrochemical properties of electrolysis cells. Through the detailed recording of impedance changes, EIS enables a well-founded assessment of the performance and efficiency of electrolysis cells in various operating states.

Electrochemical impedance spectroscopy (EIS) allows a comprehensive investigation and evaluation of cells and their components such as catalysts, membranes (MEA) and bipolar plates. This analysis not only covers the entire electrolysis stack under different operating and load conditions, but also enables the targeted investigation of individual cells or cell groups during operation.

Typically, electrolytic cells have very low impedances that continue to decrease as their active area expands during further development (electrochemical impedance is inversely proportional to active area). EIS allows these impedance changes to be precisely recorded and analyzed, providing valuable insights into the condition and performance of the cells.

To generate the impedance spectrum, the electrolytic cell is excited with a sinusoidal modulation current, which can be up to ±50A. The resulting voltage is measured over a wide frequency range to determine amplitude and phase. The impedance is calculated from the modulation current and the resulting modulation voltage. By using different measurement frequencies, the impedance spectrum is created, which provides detailed information about the electrochemical properties of the cells.

Modern electrolysis cells allow high current densities and pose a challenge for impedance measurement. The EIS meter from SIVONIC is specially designed to reliably measure the impedance spectrum even at very high working currents under various conditions. This enables users to obtain precise and reliable data for optimizing their electrolysis systems.