The degradation of Ni/yttria-stabilized zirconia (YSZ)-based solid oxide electrolysis cells operated at high current densities was studied. The degradation was examined at 850°C , at current densities of −1.0, −1.5, and −2.0A/cm2 , with a 50:50 (normalH2O:normalH2) gas supplied to the Ni/YSZ hydrogen electrode and oxygen supplied to the lanthanum, strontium manganite (LSM)/YSZ oxygen electrode. Electrode polarization resistance degradation is not directly related to the applied current density but rather a consequence of adsorbed impurities in the Ni/YSZ hydrogen electrode. However, the ohmic resistance degradation increases with applied current density. The ohmic resistance degradation is attributed to oxygen formation in the YSZ electrolyte grain boundaries near the oxygen electrode/electrolyte interface.

Solid-oxide fuel cells (SOFCs) are electricity generators that can convert the chemical energy in various fuels directly to the electric power with high efficiency. Recent advances in materials and related key components for SOFCs operating at ≈500 °C are summarized here, with a focus on the materials, structures, and techniques development for low-temperature SOFCs, including the analysis of most of the critical parameters affecting the electrochemical performance of the electrolyte, anode, and cathode. New strategies, such as thin-film deposition, exsolution of nanoparticles from perovskites, microwave plasma heating, and finger-like channeled electrodes, are discussed. These recent developments highlight the need for electrodes with higher activity and electrolytes with greater conductivity to generate a high electrochemical performance at lower temperatures.

Lithium-sulfur batteries (LSBs) show promise as commercial batteries for electric vehicles (EV), portable devices and grid storage due to its low cost and high theoretical energy density. For EV applications, the areal capacity of LSBs needs to reach ~6 mAh.cm -2 to compete with the state-of-the-art LIBs. However, currently the practical application of LSBs is a great challenge due to low sulfur loading, self-discharge and low sulfur utilization. As such, different strategies have been investigated to improve the feasibility of LSBs at high sulfur loading. Such approaches are critical, but few articles have focused on the areal capacity at high sulfur loading and long term cycling performance of LSBs. This review highlights the recent progress of LSBs at high sulfur loading to achieve feasible areal capacity and long-term cycling performance. Particular attention has been placed on the cathode and separators modifications, with a discussion around anode and electrolyte modifications to improve the LSB performance.

Reduction of H 2 O and CO 2 as well as oxidation of H 2 and CO was studied in a Ni/YSZ electrode supported Solid Oxide Cell (SOC) produced at DTU Energy conversion (former Risø DTU). Even though these Ni/YSZ based SOCs were developed and optimized for fuel cell use, they can work as reversible SOCs in mixtures of H 2 O, H 2 , CO 2 and CO. From polarization (i-V) and electrochemical impedance spectroscopic characterization, it is evident that, electrochemical reduction of both CO 2 and H 2 O occurs during coelectrolysis of H 2 O and CO 2 in these Ni/YSZ based SOC. During co-electrolysis, the equilibrium of the water gas shift reaction is reached, and CO is therefore produced via the water gas shift reaction also. Significant differences during oxidation/reduction in H 2 O -H 2 and CO 2 -CO mixtures were observed implying that different reaction mechanisms apply for the mixtures.

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