同时使用受污染的空气和铝合金端板对燃料电池耐久性的影响与失效分析

除了阅读获取不知道的知识，我在文章中发现了四处待商榷之处，你也可以来试试。

The synergetic effect of air pollutants and metal ions on performance of a 5 kW proton－exchange membrane fuel cell stack

Meng Xie

Qing Zhang

Daijun Yang

Tiankuo Chu

Bing Li

Pingwen Ming

Cunman Zhang

Summary

Large－scale commercialization of the proton－exchange membrane fuel cell （PEMFC） is primarily hindered by cost and availability． In the presence of acidic air pollutants， metal ions impact on the durability of PEMFC． This study aimed at determining the effects of metal ions such as Al3＋ and Fen＋ that originate from the corrosion of aluminum alloy end plate or other metal components， on the performance of a 5 kW PEMFC stack under the synergetic effect of air pollutants． Results obtained from the 500 hours durability test indicated that performance decreased from an initial of 0．682 V to a final 0．623 V at a current density of 1000 mA cm−2． Findings of the energy dispersive spectrometer （EDS） characterization revealed that corrosion was predominant at the air inlet and outlet of the end plate． Metal ions were detected in both the anode and cathode catalyst layer （CL） and proton－exchange membrane by EDS－mapping． Compared to the control， it was found that the synergetic effect of metal ions and air pollutants accelerated the degradation of stack performance． This synergetic effect can be mitigated by improving the adsorption performance of filters or avoiding the use of materials with poor corrosion resistance in fuel cell systems．

TABLE 1 Test conditions of the PEMFC stack test

温差挺小

FIGURE 1 Differences in ambient AQI during the two experiments

Only 10 days from the total 35 days of the test had a good
or above air quality index （AQI）， and the main factors
exceeding the national standard of China were PM2．5，
PM10， SO2， and NO2Only 10 days from the total 35 days of the test had a good or above air quality index （AQI）， and the main factors exceeding the national standard of China were PM2．5， PM10， SO2， and NO2

The AQI during the control experiment procedures
was good or above， except for 2 days that had slight pollution．

不太清楚控制实验中AQI是怎么控制的，原来以为比较好的方法是用管线气体或者加装了过滤器。看这个描述还不是。

非常高兴地看到高校开始关注环境、现实等各种缺陷对燃料电池的影响。

有一个关键的地方没有披露：空气是50％RH，气体是通过台架加湿，颗粒物、SO2、NO2在溶解罐中溶解，进入电堆的时候会有多少杂质？通过Nafion气气换湿Nafion也会很大程度影响进入电堆的量。做污染实验是否应该空气不加湿？

AQI是个平均概念，是否实验室附近的空气样本好于或者差于AQI指数？

比较关键的硬件：

engraved graphite plates 石墨双极板

AA6061 aluminum alloy material was used for the end plates， water and gas the inlet and outlet joints． An oxide film was formed on the surface of the aluminum alloy end plate by hard anodizing technology
（using an original thickness of 30 μm） to improve its corrosion resistance． 端板

A control durability test experiment was also performed to exclude the impact of the stack． With the exception of the stainless steel （316 L SS） that was used as the front end plate material， all the materials and test
conditions used were the same as in the previous experiment．

更换的进出气端板

De－ionized water with a resistivity of more than 18 MΩ cm was used as the coolant． 冷却液

没有披露集流板的信息

动态工况：The dynamic driving cycles were developed based on New European Driving Cycle and JP1015 operating cycle．

FIGURE 2 Polarization curves for the 500 hours durability test of FC stack

FIGURE 3 Polarization curves for the control experiment of FC stack

初始性能就有差异，一个1．3A／cm2＠0．65V，一个1．2A／cm2＠0．65V。文中为展示各节均一性，不知道是否也有差异。似乎空气质量好的电堆极化曲线更加平滑。

FIGURE 4 Images of the inlet and outlet ports of the aluminum alloy front end plate after the 500 hours durability test： A， air inlet； B， air outlet； C，hydrogen inlet； D， hydrogen outlet； E，coolant inlet； and F， coolant outlet

没有给出不锈钢进出气端板的对应状态。即使给了也没表明铝合金端板在AQI指数良好的气体中使用是否会发生表面阳极化耐腐蚀层脱落的问题。

FIGURE 5 Corrosion morphology of air outlet of the end plate

TABLE 2 Element contents of corrosion products （mass
fraction， ％） by EDS analysis

Based on mass fraction， the main chemical composition of typical AA6061 aluminum alloy is composed of： Si0．4％ to 0．8％， Fe 0．7％， Cu 0．15％ to 0．4％， Mn 0．15％， Mg0．8％ to 1．2％， Cr 0．04％ to 0．35％， Zn 0．25％， and Ti 0．15％， while Al comprises the other portion．

空气入口铝合金端板发生腐蚀需要更深入的分析，为什么氢气入口和出口、去离子水的入口和出口铝合金端板不发生腐蚀，是因为PM2．5， PM10， SO2， and NO2这些污染产物的影响么？

缺少原始铝合金钝化后的样本EDX数据。如果是非均匀腐蚀产物有铁镍富集有些想不通。

查了一份国标GB／T 3190－2020 变形铝及铝合金化学成分，

文章中的元素分析6061是引用数据，没有镍的，从标准中看6061的镍应该是在检出限以下的，文章也没有做空白试验，因此我个人认为：文章中说空气腔口的物质是腐蚀产物是错误的。

这个元素分布的说明有些复杂，简单说B、D、F分别是Al、Fe、Ni。新样品H、I、J分别是Al、Fe、Ni。

TABLE 3 Metal elements content within MEA （mass percentage， ％） ICP测试结果，没有初始新鲜样品的结果。

TABLE 4 Content of elements in the exhaust water （mg L−1）

这里有一个错误，ICP方法测试不了氟元素，也不知道这个数据怎么来的。

这里有一个错误，亚硫酸变成硫酸没有那么简单，需要五氧化二钒做催化剂。在自然中酸雨需要由空气中PM催化，但是不会这么快。

解释了膜电极中铝的来源，但是铁和镍，尤其是镍并未说明。我个人倾向是加湿系统的管线或者集流板的污染。

文章在这里缺少可控空白实验的关于材料的信息披露，比如膜电极的元素分析、尾液分析。

First， in the previous tests， we used 316 L SS end plate for durability test． The performance degradation of the stack was very stable， and there was no similar phenomenon of sharp decline in such a short time．
Second， in order to eliminate the impact of test error， we used 316 L SS end plate in the control experiment． Except for the change of end plate and air quality， the materials， the test equipment， parameters， and even testers used in the control experiment were not changed，which are completely consistent with the daily test and the initial test．

CONCLUSIONS

In this study， the synergetic effects of air pollutants and metal ions on PEMFC stack performance were analyzed systematically． A 5 kW PEMFC stack was assembled and the 500 hours durability test performed．
The polarization curves showed that the performance of the stack decayed sharply during 400 to 500 hours． The disassembly and characterization results showed that the air inlet and outlet were significantly corroded while metal elements were present in the MEA． Finally， the synergetic effect mechanism of air pollutants and metal ions was discussed．
The main outcomes of this study can be summarized as：

The 500 hours durability test revealed that stack performance decreases slowly in the first 400 hours with a decay rate of 70 μV h−1， while in the last 100 hours， the performance decreases sharply with a decay rate of 310 μV h−1． The decay rate in the control experimentwas 52 μV h−1．

最后七天（400－500hr）的AQI并不比前400hr的AQI差，这是一个问题。

如果空气中的杂质的溶解对膜电极能产生如此大的影响，为什么不会溶解在加湿阶段的液体中，被截留（可以测试一下增湿液的pH值），甚至影响后面的500hr测试。

The measured polarization curves in the follow－up control experiment are shown in Figure 3．

尽管文章中有对比实验，但是我个人观点铝合金端板的嫌疑比重大一些，并未有效体现出协同效应。

The stack was disassembled after performing the 500 hours durability test， and it was found that the corrosion degree in the air outlet was the most significant．
SO2 and NO2 in the air absorb and dissolve into water and generate H＋， SO42−， and NO3−， which further reduces the pH value of water film on the surface of the aluminum alloy． This leads to acceleration of the corrosion of air outlet at the end plate．

Two main methods can be considered for mitigating the synergetic effect of air pollutants and metal ions： developing air filters with both physical and chemical adsorption functions will reduce the impact of gas impurities on FC performance and materials with poor corrosion resistance should be avoided in FC systems．

In this study， according to the AQI and corrosion of aluminum alloy end plate， the synergistic effects of metal ions and air pollutants were qualitatively established．However， more studies should aim at establishing a quantitative relationship between the service life of the end plate， and the type， concentration of metal ions， and even air pollutants． Moreover， the coating anti－corrosion requirements of aluminum alloy end plates should also be quantified．