Theoretical analysis of the effect of boiling on the electrolysis voltage of a polymer electrolyte membrane water electrolyzer (PEMWE)
Theoretical analysis of the effect of boiling on the electrolysis voltage of a polymer electrolyte membrane water electrolyzer (PEMWE)
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沸腾对聚合物电解质膜水电解槽（PEMWE）电解电压影响的理论分析
DOI：
10.1016/j.jpowsour.2023.233143
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发表时间：
2023
影响因子：
9.2
通讯作者：
Kohei Ito
中科院分区：
文献类型：
--
作者：
Linjun Li;Hironori Nakajima;Atsushi Moriyama;Kohei Ito
聚合物电解质膜水电解器（PEMWE）中的水沸腾已经在实验上证明降低电解电压[Ito K等人，ECS Transactions. 2017; 80（8）：1117]。将沸腾引入PEMWE模型，对沸腾现象及其形成机理进行了全面的研究。首先确定通道/多孔传输层（PTL）处的气体饱和度作为PTL中气体传输的边界条件。然后，可以使用气体转移方程来确定催化剂层（CL）处的氧和氢压力。溶解氧和氢的活性被认为是在激活过电压通过一个变量（激活分数）。最后，能斯特损耗，激活，和欧姆过电压的PEMWE在很宽的温度范围内（包括非沸腾，沸腾，和气相的条件）确定的氧气和氢气的压力和气体饱和度在CL。结果表明，在非沸腾、沸腾和气相条件下，沸腾条件下的PEMWE具有最低的电解电压。沸腾可以加速通道（CH）中由气态氧和水蒸气组成的气泡的脱离。此外，剧烈沸腾通过降低CL处的氧和氢分压而显著降低能斯特损失。
Water boiling in a polymer electrolyte membrane water electrolyzer (PEMWE) has been experimentally demonstrated to reduce the electrolysis voltage [Ito K et al. ECS Transactions. 2017; 80(8):1117]. The boiling phenomenon and formation mechanism are studied comprehensively by introducing boiling into a PEMWE model. The gas saturation at the channel/porous transfer layer (PTL) is first determined as the boundary condition for the gas transfer in the PTL. Then, the gas transfer equation can be used to determine the oxygen and hydrogen pressures at the catalyst layer (CL). The dissolved oxygen and hydrogen activities are considered in the activation overvoltages through a variable (activation fraction). Finally, the Nernst loss, activation, and ohmic overvoltage of the PEMWE over a wide temperature range (encompassing non-boiling, boiling, and gas-phase-only conditions) are determined from the oxygen and hydrogen pressures and gas saturation at the CL. The results show that the PEMWE under boiling conditions has the lowest electrolysis voltage among the non-boiling, boiling, and gas-phase conditions. Boiling can accelerate the detachment of gas bubbles composed of gaseous oxygen and water vapor in the channel (CH). Furthermore, vigorous boiling significantly reduces the Nernst loss by reducing the oxygen and hydrogen partial pressures at the CL.