Piperidinium-functionalized anion exchange membranes and their application in alkaline fuel cells and water electrolysis
Piperidinium-functionalized anion exchange membranes and their application in alkaline fuel cells and water electrolysis
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DOI：
10.1039/c9ta01167f
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发表时间：
2019-04-07
影响因子：
11.9
通讯作者：
Li, Nanwen
中科院分区：
文献类型：
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作者：
Chu, Xiaomeng;Shi, Yan;Li, Nanwen
为了制备一种稳定的阴离子交换膜（AEM）用于可部署的电化学装置，具有较长的使用寿命，我们在这里提出了一系列哌啶官能化的聚（2，6-二甲基苯醚）的合成和性能，其具有沿聚合物主链沿着不同位置的哌啶基团。通过AFM分析证实，观察到长侧链型AEM（LSCPi）的明显相分离形态，这反过来使其氢氧化物电导率高于侧链型（SCPi）和标准苄基甲基哌啶鎓 AEM（BPi）。对于IEC值为1.57 meq的LSCPi膜，在20 ℃下实现了29.0 mScm（-1）的氢氧化物电导率。g（-1）。该电导率水平低于相应的基于QA的AEM（LSCQA）（20摄氏度时为38.7 mS cm（-1）），这可能是由于其低IEC伴随着低吸水率。LSCPi膜显示出优异的碱性稳定性，在80 ℃下在1 M NaOH中测试560小时后电导率保持98%，并且通过老化样品的NMR分析没有检测到明显的降解。为了证明哌啶鎓官能化的AEM的可行性，将SCPi和LSCPi膜都制造成用于H-2/O-2碱性燃料电池和AEM水电解槽应用的膜电极组件。高导电性LSCPi膜显示出良好的电池性能，在碱性燃料电池中在60 ℃下的峰值功率密度为116 mW cm（-2），在用纯水工作的AEM水电解中在50 ℃下在1.80 V下的峰值功率密度为300 mA cm（-2）。虽然在8.7小时和35小时的测试期间，在恒定电流下分别观察到碱性燃料电池和水电解槽耐久性测试的性能逐渐下降，但是通过NMR光谱对老化的AEM进行事后分析来验证具有哌啶鎓阳离子的AEM的高耐久性。目前的研究结果提供了在非原位和原位操作条件下AEM的耐久性的基本见解，并表明哌啶官能化的AEM似乎是一种有前途的材料，用于耐久的基于AEM的设备。
To produce a stable anion exchange membrane (AEM) for deployable electrochemical devices with a long lifespan, we here present the synthesis and properties of a series of piperidinium-functionalized poly(2,6-dimethyl phenylene oxide)s with different locations of piperidinium groups along the polymer backbones. A distinct phase separated morphology was observed for long side-chain-type AEMs (LSCPi) as confirmed by AFM analysis, which in turn enabled its higher hydroxide conductivity over side-chain-type (SCPi) and standard benzylmethyl piperidinium AEMs (BPi). A hydroxide conductivity of 29.0 mScm(-1) at 20 degrees C was achieved for the LSCPi membrane with an IEC value of 1.57 meq. g(-1). This level of conductivity was lower than that of the corresponding QA-based AEMs (LSCQA) (38.7 mS cm(-1) at 20 degrees C), probably as a result of its low IEC accompanied by low water uptake. The LSCPi membrane displayed excellent alkaline stability with 98% retention in conductivity after 560 h of testing in 1 M NaOH at 80 degrees C, and no obvious degradation was detected by NMR analysis of the aged sample. To demonstrate the feasibility of piperidinium-functionalized AEMs, both SCPi and LSCPi membranes were fabricated into a membrane electrode assembly for the H-2/O-2 alkaline fuel cell and AEM water electrolyzer applications. The highly conductive LSCPi membrane showed good cell performance with a peak power density of 116 mW cm(-2) at 60 degrees C in alkaline fuel cells and 300 mA cm(-2) at 1.80 V at 50 degrees C in AEM water electrolysis working with pure water. Although a gradual drop in performance was observed for both the alkaline fuel cell and water electrolyser durability testing at a constant current during the test of 8.7 h and 35 h respectively, the high durability of AEMs having piperidinium cations was verified by post-mortem analysis of aged AEMs by NMR spectroscopy. The current findings provided fundamental insights into the durability of AEMs under ex situ and in situ operating conditions and demonstrated that the piperidinium-functionalized AEM appears to be a promising material for durable AEM-based devices.