Long-term Steam Electrolysis with Electrolyte-Supported Solid Oxide Cells
Long-term Steam Electrolysis with Electrolyte-Supported Solid Oxide Cells
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DOI：
10.1016/j.electacta.2015.04.141
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发表时间：
2015-10
影响因子：
6.6
通讯作者：
J. Schefold;A. Brisse;Hendrik Poepke
中科院分区：
文献类型：
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作者：
J. Schefold;A. Brisse;Hendrik Poepke
讨论了用电解液支持的固体氧化物电解槽进行11000小时以上的水蒸气电解。该电池面积为45cm2，由掺有氧化钪/氧化铈的氧化锆电解液(6Sc1CeSZ)、CGO扩散阻挡层/粘附层、钴酸锶镧铁氧体(LSCF)氧电极和镍蒸汽/氢电极组成。在较低电流密度下初始运行2500h后，电流密度为j=0-0.9A/cm−2，蒸汽转化率为51%。这导致在847℃的电池温度下电池电压为1.185伏。平均电压退化为7.3m V/1000h(<；0.6%/1000h)，面积比电阻增加8mΩ/1000h，足以应用于实际电解槽。在整个测试过程中，电到化学能量的转换效率为100%(使用外部热源进行蒸发)。阻抗谱测量显示，退化几乎完全是由于欧姆电阻的增加。阻力增加的速度最初较快(高达40Ω/1000小时)，并在几次1000小时的运行后稳定下来。在9000小时后，可以检测到小的(非欧姆)电极退化(<；2 mV/1000小时)，叠加到欧姆退化。小的电极退化被理解为很大程度上可逆的(电解槽/燃料电池)行为的指示。
Steam electrolysis over 11000 h1with an electrolyte-supported solid oxide cell is discussed. The cell of 45 cm2area consists of a scandia/ceria doped zirconia electrolyte (6Sc1CeSZ), CGO diffusion-barrier/adhesion layers, a lanthanum strontium cobaltite ferrite (LSCF) oxygen electrode, and a nickel steam/hydrogen electrode. After initial 2500 h operation with lower current-density magnitude, the current density was set toj= -0.9 A cm−2and the steam conversion rate to 51%. This led to a cell voltage of 1.185 V at 847 °C cell temperature. Average voltage degradation was 7.3 mV/1000 h (<0.6%/1000 h), the increase in the area specific resistance was 8 mΩ cm2/1000 h, sufficiently low for application in practical electrolysers. The electrical-to-chemical energy-conversion efficiency was ηel> 100% throughout the test (with an external heat source for evaporation). Impedance spectroscopic measurements revealed a degradation almost entirely due to increasing ohmic resistance. The rate of resistance increase was initially faster (up to 40 mΩ cm2/1000 h) and stabilised after several 1000 h operation. After 9000 h a small (non-ohmic) electrode degradation became detectable (<2 mV/1000 h), superimposed to ohmic degradation. The small electrode degradation is understood as indication for largely reversible (electrolysis cell/fuel cell) behaviour.