Hydrogen Crossover in PEM and Alkaline Water Electrolysis: Mechanisms, Direct Comparison and Mitigation Strategies
Hydrogen Crossover in PEM and Alkaline Water Electrolysis: Mechanisms, Direct Comparison and Mitigation Strategies
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DOI：
10.1149/2.0541807jes
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发表时间：
2018
影响因子：
3.9
通讯作者：
P. Trinke;P. Haug;J. Brauns;B. Bensmann;R. Hanke‐Rauschenbach;T. Turek
中科院分区：
文献类型：
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作者：
P. Trinke;P. Haug;J. Brauns;B. Bensmann;R. Hanke‐Rauschenbach;T. Turek
这项研究提供了一个直接的比较，在质子交换膜（Nafion 117）和碱性水电解（锆）在应用国家的最先进的分离单元材料的温度下的氢交叉。为此，发生的交叉机制进行了描述第一，阳极氢含量的实验数据显示在依赖于电流密度，系统压力和过程管理策略之前。结果表明，PEM电解槽中的渗透主要由扩散控制，这是由于催化剂层内溶解的氢的过饱和浓度，在大气压下显示出占总渗透通量的98%。碱性电解槽中的渗透也表现出过饱和的显著影响，但总体交叉主要受混合电解质循环的影响，其占90%和90%。通常，很明显，在碱性电解中，穿过分离单元的氢渗透小一个数量级以上，这主要是浓KOH电解质中显著较低的氢溶解度的结果。最后，本研究的结论与分离单元厚度的影响的评估，并提供缓解策略，以减少氢交叉。
This study provides a direct comparison of hydrogen crossover in PEM (Nafion 117) and alkaline water electrolysis (Zirfon) at a temperature of applying state-of-the-art separating unit materials. To this end, occurring crossover mechanisms are described first, before experimental data of the anodic hydrogen content are shown in dependence of current density, system pressure and process management strategy. The results suggest that permeation in PEM electrolyzers is mainly governed by diffusion due to a supersaturated concentration of dissolved hydrogen within the catalyst layer, showing a share of 98} of the total permeation flux at and atmospheric pressure. Permeation in alkaline electrolyzers also exhibits a significant influence of supersaturation, but the overall crossover is mainly influenced by mixing the electrolyte cycles, which makes up a share of 90} at and. Generally it becomes evident that hydrogen permeation across the separating unit is more than one order of magnitude smaller in alkaline electrolysis, which is mainly a consequence of the significantly lower hydrogen solubility in concentrated KOH electrolyte. Finally, this study concludes with an assessment of the impact of separating unit thickness and provides mitigation strategies to reduce hydrogen crossover.