Notably enhanced proton conductivity by thermally-induced phase-separation transition of Nafion/ Poly(vinylidene fluoride) blend membranes
Notably enhanced proton conductivity by thermally-induced phase-separation transition of Nafion/ Poly(vinylidene fluoride) blend membranes
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DOI：
10.1016/j.jpowsour.2020.228586
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发表时间：
2020-10
影响因子：
9.2
通讯作者：
Xue-yang Yang;Haijin Zhu;F. Jiang;Xinjie Zhou
中科院分区：
文献类型：
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作者：
Xue-yang Yang;Haijin Zhu;F. Jiang;Xinjie Zhou
将全氟磺酸（例如Nafion）与其他聚合物共混是降低成本和调整耐用质子传导膜性能的有效方法。特别是聚偏二氟乙烯（PVDF）复合材料因其突出的化学/热稳定性而备受关注，并且可以增强膜的阻隔性、机械强度和加工性能。然而，这种方法的主要问题之一是 Nafion/PVDF 复合材料的质子电导率随着 PVDF 含量的增加而迅速下降。在这项工作中，我们首次证明，通过简单易行的 180°C 退火工艺，Nafion/PVDF 共混膜的质子电导率可以提高 200% 以上，并且含有 60wt% Nafion 的退火膜的质子电导率高达 45.2 mS cm−1。共混膜的阻隔性能明显优于纯 Nafion，钒离子渗透性约为 Nafion 的三分之一。在钒氧化还原液流电池的单电池测试中，含有60 wt% Nafion的退火膜在100 mA cm−2时的能量效率达到83.6%，与Nafion膜相当。退火的共混膜具有较高的化学稳定性和尺寸稳定性，这使得它们在氧化还原液流电池或燃料电池中的实际应用具有广阔的前景。
Blending perfluorosulfonic acid (e.g. Nafion) with other polymers is an effective approach to reduce the cost and adjust the properties of durable proton conducting membranes. In particular, poly(vinylidene fluoride) (PVDF) composites have attracted much attention because of its outstanding chemical/thermal stability and it can enhance the barrier property, mechanical strength and processibility of the membranes. One of the major issues with this approach, however, is that the proton conductivity of the Nafion/PVDF composite drops rapidly with increasing PVDF content. In this work, we demonstrate for the first time that through a simple and facile annealing process at 180 °C, the proton conductivity of the Nafion/PVDF blend membrane can be boosted by more than 200%, and the annealed membrane with 60 wt% Nafion shows proton conductivity as high as 45.2 mS cm−1. The barrier properties of the blend membranes are significantly superior to the neat Nafion as indicated by the vanadium ion permeability of approximately one third of the Nafion. In the single cell test of vanadium redox flow battery, the energy efficiency of the annealed membrane with 60 wt% Nafion reaches 83.6% at 100 mA cm−2, which is comparable to Nafion membranes. The annealed blend membranes possess a high chemical and dimensional stability, which makes them promising for practical applications in redox flow batteries or fuel cells.