Title:    Electrochemical behaviour and reactions down to low temperatures

Time:    2025-10-29 16:00

Lecturer:  Prof. Ulrich Stimming

Technical University of Munich, Germany

Venue:    Room 202, Lu-Jiaxi Building

Abstract：

The seminar describes the electrochemical behaviour and interfacial reactions down to low temperatures using the Frozen Electrolyte Electrochemistry (FREECE) technique. By employing stoichiometric acid (or hydroxide) hydrates such as HClO₄·5.5H₂O, electrochemical measurements can be extended down to 4 K enabling the study of protons in the electrolyte and temperature effects on proton transfer and charge‐transfer kinetics. Proton tunnelling seems to be dominant below 80 K. Solidification of the electrolyte does not alter the electrochemical double layer for various metals including mercury, where a transition liquid-liquid to solid-solid occurs within 10K. Kinetic measurements of hydrogen and oxygen evolution show a strong temperature effect on the transfer coefficient indicating an influence of the entropy of activation. In some cases, the activation energy even increases with increasing overpotential of the reaction being overcompensated by a strong potential dependent entropy of activation still resulting in a Butler-Volmer type of behaviour. These findings call for a revision of the typically assumed influence of the electrode potential on the activation energy. Only measurements in a wide range of temperature can reveal such effects. These findings provide a molecular-level insight into the interplay of thermal, electric-field, and quantum effects governing electrochemical reactions.

Bio of the Lecturer：

Ulrich Stimming is Professor Emeritus of Physics and Chemistry of Technical University of Munich and of Physical Chemistry at Newcastle University. He was CEO, Scientific Advisor and Principal Investigator of TUM Create in Singapore. He is the founder and former Editor-in-Chief of the scientific journal “Fuel Cells-From Fundamentals to Systems”, VCH-Wiley. He coordinated for the Association of Leading Technical Universities in Germany (TU9) a research network on electromobility of 8 universities in Germany and China and was the co-director of the Joint “Institute for Advanced Power Sources” of TU Munich and Tsinghua University. He received awards like the Pergamon Gold Medal of I.S.E. and has >300 publications and an h-index of 83.