In his career Fichtner worked on various topics, covering Theoretical Chemistry, Instrumental Analysis, Higher Administration, Chemical Engineering, Heterogeneous Catalysis, Hydrogen Storage, Electrochemistry and Battery Research.
Pioneering achievements were the first measurements of salts with Secondary Neutral Mass Spectrometry, the development of a depth-resolved speciation of beam sensitive salts, a microstructure reactor which could safely burn and transfer the heat from a stoichiometric hydrogen-oxygen mixture to a thermo oil, thus demonstrating the enormous capability of running dangerous reactions in microstructure reactors safely.
In the development of hydrogen storage materials, new complex hydride compounds were synthesized and investigated, the fasted charge and discharge of an aluminum hydride to date by a new Ti13 catalyst, first applied for that purpose by the Bogdanovig group of Max Planck Mülheim, was independently confirmed. Further work in this area was focused on elucidating nanoscale effects in energy materials and studies, based on pioneering work since the late 1990s by various groups from all over the world on hydrogen and the effects by nanostructures, of the change of thermodynamic properties of complex hydrides was conducted in his group.
In battery research, new synthesis methods were developed to stabilize conversion materials, new types of batteries based on anionic shuttles were presented and new electrolytes were developed for magnesium properties with outstanding voltage windows and non-nucleophilic properties, making reversible Mg-S cells possible. Moreover, a new class of cathode materials is being studied with the highest packing densities for Li ions to date, the so-called Li-excess disordered rocksalt materials (DRX), developed by the Gerbrand Ceder group.