Enhancing PEM water electrolysis efficiency by reducing the extent of Ti gas diffusion layer passivation
Enhancing PEM water electrolysis efficiency by reducing the extent of Ti gas diffusion layer passivation
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DOI：
10.1007/s10800-018-1174-6
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发表时间：
2018-06-01
影响因子：
2.9
通讯作者：
Bouzek, K.
中科院分区：
文献类型：
--
作者：
Bystron, T.;Vesely, M.;Bouzek, K.
质子交换膜水电解（PEM WE）存在几个问题，例如电解槽单元部件的高成本和低稳定性。对于极化至高电位并与酸性膜接触的阳极来说，这一点尤其明显。这样的组合对绝大多数电子传导材料是有害的。目前，Ti（在其表面上具有保护性钝化层）被用作阳极气体扩散层的构造材料。由于钝化层本身是非半导体/半导体的，因此过度程度的钝化导致高表面接触电阻和PEM WE操作期间的能量损失。这个问题通常通过用贵金属涂覆Ti表面来解决。这导致已经非常高的电池投资成本的进一步增加。在这项工作中，提出了一种基于适当的钛蚀刻（在酸中）的替代方法。用扫描电镜、X射线荧光、衍射和光电子能谱研究了处理后样品的表面组成。在次表层中发现了TiHx。这是防止钛金属过度钝化的原因。在电流密度高达1 A cm（- 2）的（> 100 h）实验期间，证实了蚀刻的Ti气体扩散层（与未蚀刻的相比）在PEM水电解槽中的上级性能。使用所描述的处理，表面接触电阻显著降低，并且在PEM WE操作期间其增加被大大抑制。由于这种方法非常简单和便宜，它具有巨大的潜力，提高PEM WE工艺效率。[图形]。
Proton exchange membrane water electrolysis (PEM WE) suffers from several issues, such as the high cost and low stability of the electrolyser unit components. This is especially evident for an anode polarised to a high potential and in contact with an acidic membrane. Such a combination is detrimental to the vast majority of electron-conducting materials. Nowadays Ti (possessing a protective passive layer on its surface) is used as the construction material of an anode gas diffusion layer. Since the passivation layer itself is non-/semiconducting, an excessive degree of passivation leads to high surface contact resistance and to energy losses during PEM WE operation. This problem is usually solved by coating the Ti surface with precious metals. This leads to a further increase of the already very high cell investment costs. In this work an alternative method based on appropriate Ti etching (in acid) is presented. The (surface) composition of the samples treated was investigated using SEM, X-ray fluorescence and diffraction and photoelectron spectroscopy. TiHx was found in the subsurface layer. This was responsible for preventing excessive passivation of the Ti metal. The superior performance of the etched Ti gas diffusion layer (compared to non-etched) in a PEM water electrolyser was confirmed during an (> 100 h) experiment with current densities of up to 1 A cm(- 2). Using the described treatment the surface contact resistance was substantially reduced and its increase during PEM WE operation was largely suppressed. As this method is very simple and cheap, it has tremendous potential for improving PEM WE process efficiency.[GRAPHICS].