Modelling and DC-polarisation of a three dimensional electrode/electrolyte interface

A finite element model (FEM) was developed which is able to calculate and predict the electrical performance of a solid oxide fuel cell (SOFC) with a three dimensional interface between cathode and electrolyte. An enlargement of the electrochemical active surface leads to a significant increase of the electrical performance of a SOFC. Various three dimensional electrolyte/electrode interfaces have been realized by first screen printing of individual 10YSZ particles onto a flat and dense 8YSZ substrate. Surface enlargements between 10 and 50% have been realised and investigated. Second, a screen printed cathode (LSM) layer was applied as a current collector and gas distribution layer. In order to develop a FEM-model for this type of cathode/electrolyte interface, several electrical properties of cathode (LSM) and electrolyte (8YSZ) were examined. Further on, measurements of symmetrical cells (LSM/8YSZ/LSM) to evaluate the electrode resistance R0 were carried out for different symmetrical cells. Taking into account the enlargement of the interface surface, electrical conductivity and electrode resistance R0, the entire DC polarisation-resistance Rpol could be calculated by FEM.