A hemispherical electrolyte probe for screening of solid oxide fuel cell cathode materials

A hemispherical electrolyte probe (HEP) technique has been adapted and introduced as a method to rapidly characterize potential cathode materials for solid oxide fuel cells. The technique was used to measure the linear-specific triple phase boundary (TPB) resistance of electronic conductors La_0.8Sr_0.2MnO₃ (LSM) and (La_0.87Ca_0.13)_0.95MnO₃ (LCM), along with the area-specific surface resistance of mixed ionic/electronic conductors (MIECs) Sr_0.5Sm_0.5CoO_3-δ (SSC), and La_0.6Sr_0.4Fe_0.8Co_0.2O_3-δ (LSFC). These parameters are measures of the catalytic performance of the cathode materials, independent of the electrode geometry. HEP-measured linear-specific TPB resistance and surface resistance values are consistently lower by a factor of ∼3 compared with literature values for these materials, while activation energies are in fair agreement with the literature values. The technique could be useful for comparative rapid screening of candidate cathode materials. Alternatively, good estimates of linear-specific TPB resistance or area-specific surface resistance values can be obtained using a HEP probe that has been calibrated with a known standard.