Polyethyleneimine‐functionalized reduced graphene oxide (PEI‐RGO)‐embedded sulfonated poly (vinylidene fluoride‐co‐hexafluoropropylene) (SPVDF‐co‐HFP) acid‐base composite membranes are fabricated by solution casting method for vanadium redox flow battery (VRFB) applications. The denser and crumbled morphology revealed by FESEM images and EDX results indicates the successful synthesis of PEI‐RGO nanosheets. The interfacial acid‐base pairs formed between PEI‐RGO and SPVDF‐co‐HFP matrix of composite membranes result in improvement of ion exchange capacity, water uptake, proton conductivity, as well as effective control in swelling ratio and vanadium‐ion permeability. In addition, the dispersing ability of PEI‐RGO in the SPVDF‐co‐HFP matrix improved the thermal and mechanical stability of the composite membranes. Homogeneous dispersion of PEI‐RGO nanosheets at the SPVDF‐co‐HFP surface is revealed by the FESEM images of the composite membranes, and their presence is confirmed by EDX results. The SPVDF‐co‐HFP membrane with 0.75 wt% PEI‐RGO exhibited the highest proton conductivity of 5.69 × 10⁻³ Scm⁻¹ at 25°C, membrane selectivity of 25.52 × 10⁻⁴ Scm⁻³min, and lowest vanadium‐ion permeability of 2.23 × 10⁻⁸ cm²min⁻¹. Overall results suggested that the SPVDF‐co‐HFP‐0.75 nanocomposite membranes are found to be a suitable alternative for commercially costly Nafion in VRFB applications.

中文翻译：

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具有高选择性，稳定性和钒离子阻挡层的磺化聚偏二氟乙烯-共-六氟丙烯纳米复合膜，用于钒氧化还原液流电池

聚乙烯亚胺官能化的还原氧化石墨烯（PEI-RGO）嵌入的磺化聚偏二氟乙烯-共-六氟丙烯（SPVDF-co-HFP）酸基复合膜是通过溶液浇铸法制造的，用于钒氧化还原液流电池（VRFB）应用。FESEM图像和EDX结果显示出致密而破碎的形态，表明PEI-RGO纳米片的成功合成。复合膜的PEI-RGO和SPVDF-co-HFP基质之间形成的界面酸碱对可改善离子交换容量，吸水率，质子传导率，并有效控制溶胀率和钒离子渗透性。此外，PEI-RGO在SPVDF-co-HFP基质中的分散能力提高了复合膜的热稳定性和机械稳定性。PEI-RGO纳米片在SPVDF-co-HFP表面上的均匀分散通过复合膜的FESEM图像显示，并且它们的存在通过EDX结果得到证实。含0.75 wt％PEI-RGO的SPVDF-co-HFP膜表现出5.69×10的最高质子传导率在25°C下为^-3 Scm ^-1，膜选择性为25.52×10 ^-4 Scm ^-3 min，最低钒离子渗透性为2.23×10 ^-8 cm ² min ^-1。总体结果表明，SPVDF-co-HFP-0.75纳米复合膜是VRFB应用中商业上昂贵的Nafion的合适替代品。