Lin Jingjing, Wang Peng, Bin Jinsheng, Wang Lei
Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China.
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
Small. 2024 Jul;20(29):e2311767. doi: 10.1002/smll.202311767. Epub 2024 Feb 19.
Enhancing phosphoric acid (PA) doping in polybenzimidazole (PBI) membranes is crucial for improving the performance of high-temperature proton exchange membrane fuel cells (HT-PEMFCs). However, excessive PA uptake often leads to drawbacks such as PA loss and compromised mechanical properties when surpassing PA capacity of PBI basic functionality. Herein, a new strategy that integrates high PA uptake, mechanical strength, and acid retention is proposed by embedding linear PBI chains into a crosslinked poly(N-vinylimidazole) (PVIm) backbone via in-situ polymerization. The imidazole (Im)-riched semi-interpenetrating polymer network (sIPN) membrane with high-density nitrogen moieties, significantly enhancing the PA doping degree to 380% shows an excellent conductivity (0.108 S cm). Meanwhile, the crosslinking structure in the sIPN membrane ensures adequate mechanical properties, low hydrogen permeability, and a relatively low swelling ratio. As a result, the single cell based on the membrane achieves the highest power density of 1060 mW cm with a low Pt loading (0.6 mg cm) up to now and exhibits excellent fuel cell stability.
提高聚苯并咪唑（PBI）膜中的磷酸（PA）掺杂量对于提升高温质子交换膜燃料电池（HT-PEMFCs）的性能至关重要。然而，当超过PBI基本官能团的PA容量时，过量的PA吸收往往会导致诸如PA损失和机械性能受损等缺点。在此，通过原位聚合将线性PBI链嵌入交联的聚（N-乙烯基咪唑）（PVIm）主链中，提出了一种整合高PA吸收、机械强度和酸保留的新策略。具有高密度氮部分的富含咪唑（Im）的半互穿聚合物网络（sIPN）膜，显著将PA掺杂度提高到380%，显示出优异的电导率（0.108 S cm）。同时，sIPN膜中的交联结构确保了足够的机械性能、低氢渗透率和相对较低的溶胀率。结果，基于该膜的单电池在低铂负载（0.6 mg cm）下实现了迄今为止最高的功率密度1060 mW cm，并表现出优异的燃料电池稳定性。
