Infiltration of ionic-, electronic- and mixed-conducting nano particles into La0.75Sr0.25MnO3–Y0.16Zr0.84O2 cathodes – A comparative study of performance enhancement and stability at different temperatures

The microstructure and electrochemical performance of LSM–YSZ composite electrodes infiltrated with La0.8Sr0.2MnO3−δ (LSM) as an electronic conductor, LaCo0.6Ni0.4O3−δ (LCN) as a mixed conductor and Ce0.8Gd0.2O2−δ (CGO) as an ionic conductor, were compared in the temperature range 550–800 °C. All three infiltrates resulted in improved electrochemical performance. Impedance analysis suggested dissociative adsorption and transfer of species to the triple phase boundary as the main mechanism responsible for the performance enhancement in all cases, attributed to the increase in surface area and triple phase boundary upon infiltration. LCN showed the most pronounced improvement at 550 °C, but its performance degraded drastically with increasing temperature. LSM and CGO infiltrated electrodes degraded less upon heating up to 800 °C. Infiltrated CGO electrodes showed the smallest degradation rate upon long term testing at 750 °C.

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► In situ formation of nano particles leads to performance increase.
► Polarization resistance Rp decreased by more than 70%.
► The performance increase strongly differs with temperature and type of infiltrate.
► Mechanism of the performance increase independent from electrochemical properties.