The research group of Prof. Eichelbaum focusses on new CO2-neutral ways to produce green hydrogen, i.e., via electrolysis and photo(electro)catalysis, on the electrochemical conversion of CO2 to important chemicals and energy carriers, and on the in situ and ex situ analysis of hydrogen polymerelectrolyte (PEM) fuel cells in real applications. Understanding degradation mechanisms and the extension of fuel cell lifetimes is a key topic across all of their work. The degradation of fuel cells is investigated by newly developed accelerated stress tests (AST) and the components are characterised by various analytical methods such as cyclovoltammetry (CV), eletrochemical impedance spectroscopy (EIS), X-ray fluorescence microscopy (XRF), mass spectrometric (MS) gas analysis, product water analysis by voltammetry and inductively-coupled plasma optical emission spectroscopy (ICP-OES), and surface conductivity analysis by scanning electrochemical microscopy (SECM). The results are compared with fuel cells degraded on engine test benches and in truck field tests, and the laboratory ASTs are adapted to reflect more realistic degradation conditions. In the long run, regeneration methods are developed to increase the lifetime of fuel cells. For this purpose, machine learning methods are applied to predict fuel cell degradation and to develop virtual sensors.