Improvement of Electrode Performance on the Alkali Metal Thermal to Electric Converter

本文提出并讨论了用于碱金属热电转换器（AMTEC）的微米尺度集流引线。电流收集引线直接沉积在固体β -氧化铝电解液的阴极侧表面，以消除传统的固定金属网的必要性。新的电流收集引线还减少了AMTEC设备阴极侧电极的电和传质电阻。钠通过多孔电极的传质特性强烈影响AMTEC循环的输出性能。电极电阻和多孔电极与集流器之间的接触电阻也会导致AMTEC循环中输出功率的显著降低。为了提高整体性能，必须同时提高传质和电阻。微米级电流引线有可能降低整体电阻，而质量传输电阻的增加更小。介绍了一种新型的钠暴露试验电池（SETC），用于测试多孔钼电极的传质特性。对测量的性能进行了检验，并介绍了电极上的质量传递模型。另一方面，对引线的电特性进行了实验研究。采用氩激光诱导热CVD法制备钼的电流引线。研究了沉积条件（如压力、激光功率和写入速度）对成形引线宽度和厚度的影响。电阻也被测量，测得的沉积引线的体积电阻是大块钼的4-6倍。并根据实测数据进行了分析。各种配置包括最佳宽度，距离和厚度计算。将直接沉积引线电极性能与传统扎堆式集电极性能进行了比较，结果表明，在体积电阻较低的情况下，其功率密度也提高了35%左右。验证了本文提出的电流引线结构的有效性。如果沉积引线的体积电阻能够得到改善，那么这种方法有望获得更高的性能。少

Micron-scale current collection leads for the Alkali Metal Thermal to Electric Converter (AMTEC) have been proposed and discussed in this study. The current collection leads are directly deposited on cathode side surfaces of the solid beta"-alumina electrolyte to eliminate the necessity for the conventional tied-on metal meshes. The new current collection leads also reduce electrical and mass transfer resistance in the cathode side electrodes of the AMTEC devices.The mass transport characteristics of sodium through the porous electrode strongly influence the output performance of the AMTEC cycle. Electrode electrical resistance and contact resistance between the porous electrode and the current collector also cause significant lowered power output in the AMTEC cycle. In order to improve the overall performance, both mass transport and electrical resistance must be improved simultaneously. The micron-scale current leads have a possibility to lower the overall electrical resistance with … More small increase in the mass transport resistance.The sodium exposure test cell (SETC) was newly fabricated and used to measure the mass transfer characteristics in the porous molybdenum electrode. The measured performance was examined and a mass transport model on the electrodes was introduced. On the other hands, the electrical characteristics of the leads were experimentally examined. The current leads of molybdenum were linearly deposited by Ar laser-induced thermal CVD method. The influence of depositing conditions, such as pressure, laser power, and writing speed, on the formed width and thickness of the leads was examined. The electrical resistance was also measured and the measured volumetric resistance of the deposited leads was 4-6 times as high as that of the bulk molybdenum.The analysis based on the measured data was also conducted. Various configurations include optimum width, distance and thickness were calculated. Compared result of the electrode performance having direct deposited current leads with that of the conventional tied-on collector has shown that its power density is about 35% higher even with its low electrical volumetric resistance. The effective of the current lead structure proposed in this study was verified. If the volumetric resistance of the deposited leads can be improved, much higher performance is expected with this method. Less