Pulsed laser deposited La_0.6Sr_0.4CoO_3−δ (LSC) thin film electrodes on yttria stabilized zirconia (YSZ) single crystals were investigated by impedance spectroscopy, time of flight secondary ion mass spectrometry (ToF-SIMS) and inductively coupled plasma optical emission spectrometry (ICP-OES). Effects caused by different film deposition temperatures, thermal annealing and chemical etching were studied. Correlations between changes in electrode polarization resistance of oxygen reduction and surface composition were found. At high deposition temperatures and after thermal annealing an inhomogeneous cation distribution was detected in the surface-near region, most manifest in a significant Sr enrichment at the surface. An activating effect of chemical etching of LSC is described, which can lower the polarization resistance by orders of magnitude. Chemistry behind this activation and thermal degradation was analyzed by ToF-SIMS and ICP-OES measurements of in-situ etched LSC films. The latter allow quantitative depth resolved compositional analysis with nominally sub nm resolution. High resolution scanning electron microscopy images illustrate the accompanying changes in surface morphology. All measurements suggest that stoichiometric LSC surfaces intrinsically exhibit very high activity towards oxygen reduction.

For applications in automotive, aviation and renewable energy industries temperature and power requirements have been significantly increased for electronic components. In particular, capacitors have been identified as the most critical materials considering the fulfillment of these requirements. Ceramics are the most promising materials for high temperature capacitors but no ceramic has been able to meet the necessary electrical properties so far. In this work, Na_1/2Bi_1/2TiO₃ (NBT) solid solutions are investigated to optimize the respective electrical properties. A reduction of bismuth vacancy and oxygen vacancy concentration by increasing the initial Bi content leads to a significant decrease in dielectric loss. Additionally, energy efficiencies of up to 97% can be achieved for the composition Na_1/2Bi_1/2O₃–BaTiO₃–CaZrO₃ (NBT–BT–CZ) and the temperature range of stable high permittivity together with low dielectric loss (tan δ ≤ 0.02) extends from −67 °C to 362 °C. Hence, optimization of the defect chemistry of NBT-materials results in highly stable electrical properties over a large temperature and electric field range, which leads to the fulfillment of industrial requirements.