Novel air-electrode materials for low-cost inert-supported solid oxide cells: investigation of materials compatibility during co-sintering

Abstract

AbstractFor the investigation of the reactivity of alternative solid oxide cell air electrode materials with forsterite (Mg2SiO4), a magnesium silicate doped with Zn and Ca, five different phase materials were chosen: two Ruddlesden–Popper phase materials: La4Ni3O10 (L4N3) and La3Ni2O7 (L3N2) and three titanium-based perovskite materials: SrTiO3 (STO), SrTi0.75Fe0.25O3 (STF25) and CaTi0.9Fe0.1O3 (CTF). Forsterite was chosen as a support material for the fuel cell, as it is abundant and therefore relatively inexpensive. For the investigation of their reactivity, different types of samples were prepared: mixed pellets, double-layered pellets and screen-printed electrode inks on forsterite green substrates, which were subsequently co-sintered at T = 1300 °C. These samples and their cross sections were then studied using XRD, SEM, EDS and TEM lamella point analysis. Consequently, the impedance spectra were acquired to determine their electro-catalytic performance. The two Ruddlesden–Popper phase materials L4N3 and L3N2 are of high interest due to their thermodynamic stability and high electro-catalytic activity, resulting in a very low polarization resistance. However, this polarization resistance is increased when mixing with forsterite material. In case of the three titanium-based perovskites, the electro-catalytic activity is of less interest due to high polarization resistances.