Alkali-doped polyvinyl alcohol - Polybenzimidazole membranes for alkaline water electrolysis
Alkali-doped polyvinyl alcohol - Polybenzimidazole membranes for alkaline water electrolysis
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DOI：
10.1016/j.memsci.2017.04.021
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发表时间：
2017-08-01
影响因子：
9.5
通讯作者：
Ocon, P.
中科院分区：
文献类型：
--
作者：
Diaz, L. A.;Coppola, R. E.;Ocon, P.
我们开发了一种由聚乙烯醇（PVA）和聚苯并咪唑组成的创新聚合物共混系统作为阴离子膜，应用于零间隙碱性电解槽。面临的挑战是将 PVA 与聚[2-2'-(间亚苯基)-5-5'-联苯并咪唑] (PBI) 或聚 (2,5-苯并咪唑) (ABPBI) 相结合，以补充这些中性聚合物，这些中性聚合物必须掺杂才能传导，羟基基团有利于 OH- 传输机制。我们研究了 PVA-PBI 和 PVA-ABPBI 膜，其成分在 2:1 至 8:1 之间变化，其中 4:1 是最佳比例。通过将PVA-PBI 4:1和PVA-ABPBI 4:1膜浸入不同GA含量（0.5 vol%至50 vol%）的反应溶液中，PVA与戊二醛（GA）进行交联，以增强膜的稳定性。分析了线性碱掺杂（L-PVA-PBI、L-PVA-ABPBI）和交联（C-PVA-PBI、C-PVA-ABPBI）膜在 KOH 环境中的化学稳定性、热性能和机械性能、表面形貌、膨胀、水/KOH 吸附和电导率。在 0.5 vol% GA 中交联的 C-PVA-ABPBI 4:1 膜观察到最好的结果，当使用 15 wt% 和 30 wt% KOH 掺杂时，其在 90 摄氏度下的电导率分别为 50 mS cm(-1) 和 90 mS cm(-1)。在 50 摄氏度下使用循环的 15 wt% KOH 进行的短期电解测试中，该膜在电池电压为 2.0 V 时表现出的电流密度是商业多孔 Zirfon((R)) 隔膜的两倍（即分别为 300 mA cm(-2) 和 140 mA cm(-2)）。在 15 wt% KOH 电解质中使用 C-PVA-ABPBI 膜实现的性能70 摄氏度较好（即，电池电压为 1.9 V 时电流为 360 mA cm(-2)）。
We developed an innovative polymer blend system composed of polyvinyl alcohol (PVA) and polybenzimidazole as an anionic membrane for application to zero gap alkaline electrolysers. The challenge was to combine PVA with either poly[2-2 '-(m-phenylene)-5-5 '-bibenzimidazole] (PBI) or poly (2,5-benzimidazole) (ABPBI) to complement these neutral polymers, which must be doped to conduct, with hydroxyl groups that benefit the OH- transport mechanism. We studied PVA-PBI and PVA-ABPBI membranes with compositions varying between 2: 1 and 8: 1, with 4: 1 being best ratio. PVA is crosslinked inside PVA-PBI 4:1 and PVA-ABPBI 4: 1 membranes with glutaraldehyde (GA) by immersion in a reaction solution with different GA contents ranging from 0.5 vol% to 50 vol% to enhance the stability of the membranes. The chemical stability in a KOH environment, thermal and mechanical properties, surface morphology, swelling, water/KOH sorption, and conductivity of the linear alkali-doped (L-PVA-PBI, L-PVA-ABPBI) and crosslinked (C-PVA-PBI, C-PVA-ABPBI) membranes were analysed. The best results were observed for the C-PVA-ABPBI 4:1 membrane crosslinked in 0.5 vol% GA, which exhibited specific conductivities at 90 degrees C of 50 mS cm(-1) and 90 mS cm(-1) when doped using 15 wt% and 30 wt% KOH, respectively. In short-term electrolysis tests performed with circulated 15 wt% KOH at 50 degrees C, this membrane exhibited a current density that was twice that of the commercial porous Zirfon((R)) diaphragm (i.e., 300 mA cm(-2) and 140 mA cm(-2), respectively) at a cell voltage of 2.0 V. The performance achieved with the C-PVA-ABPBI membrane in a 15 wt% KOH electrolyte at 70 degrees C was good (i.e., 360 mA cm(-2) at a cell voltage of 1.9 V).