Fuel cells based on solid oxides (‘SOFC’) are excellent alternative devices for power generation, when they are operated at high temperature, e.g. above 600°C. Having only fixed parts for the power generating part of the device is only one advantage of the fuel cell. Due to their unique design, these devices offer a maximum of efficiency for energy conversion compared to conventional power generating systems, which are mainly based on turbines. One aim of this thesis is the examination of alternative electrolyte and cathode materials for the SOFC applications at reduced temperatures, which means in the temperature range between 600°C and 750°C. For the first main task, several materials from the oxygen ion conducting electrolytes were selected. Different strontium and magnesium doped lanthanum gallate (LSGM) materials with additional transition metal doping were selected and prepared via two different preparation methods. The optimum calcining conditions were determined using thermal analysis methods. The results of the structural analysis of the sintered electrolyte materials were used to select the most suitable electrolyte materials. As a result, LSGM and iron doped LSGM (LSGMF) were the most promising materials. Further investigations were carried out on LSGMF materials with different strontium content. The influence of chemical cation non-stoichiometry on the perovskite material was investigated. Therefore, measurements to gather information about the crystallographic structure, morphology, electrochemistry and electrical conductivity were carried out. For a selected sample, the correlations between single effects, such as the crystallographic structure, and the electrical properties are shown by combining the different analysis methods. It could be shown that both the electrochemistry and the crystallographic structure have a significant influence on the electrical conductivity of the LSGMF materials. The second aim of the thesis was the selection and preparation of suitable cathode materials for the SOFC operated at reduced temperatures. The focus for this selection was laid on the chemical compatibility with LSGMF and Scandia doped yttria (ScSZ) based electrolyte materials. Most of the cathode materials could be prepared single phased, with the exception of a strontium doped lanthanumcuprate and a strontium doped lanthanumnickelate. The third aim of the thesis was the investigation of the chemical compatibility between the prepared cathode materials and the electrolyte materials ScSZ and LSGM. The combinations of electrolyte-cathode materials were annealed at commonly used co-sintering temperatures but for extended sintering times. X-Ray diffraction patterns (XRD) and scanning electron microscopy (SEM) were used for the investigation. Based on the examination of the appearing primary and secondary phases and the morphology a ranking of the combinations is given. The least chemical reactions with both electrolyte materials were observed for a strontium doped lanthanum manganite. However, a strontium and copper doped lanthanum-ferrite seems to be the most promising cathode material for reduced temperatures
