Sulfonated poly(ether ether ketone) (SPEEK) hybrid membranes are prepared by incorporating 2,2′-benzidinedisulfonic acid-functionalized amphoteric graphene oxide (GO-BDSA) nanosheets. The optimized membrane permeability and ion selectivity greatly regulate the vanadium flow redox battery (VRFB) performance in terms of the formed interfacial action. At a 1 wt % loading of GO-BDSA nanosheets, proton conductivity and ion selectivity of SPEEK/GO-BDSA-1 reach a maximum value such as 30.7 mS cm^–1 and 43.3 × 10³ S min cm^–3, respectively. As compared with the self-discharge time of SPEEK (38 h) and Nafion 117 (33.5 h), SPEEK/GO-BDSA-1 hybrid membrane shows a longer one, 95.3 h. In the meantime, higher voltage efficiency (VE, 92%) and energy efficiency (EE, 85%) than those of SPEEK (VE, 87% and EE, 82%) and Nafion 117 (VE, 89% and EE, 84%) are confirmed at 50 mA·cm^–2. The structure stability and durability of SPEEK/GO-BDSA-1 hybrid membrane are supposed after 250-time charge–discharge test, which is ascribed to the interaction of GO-BDSA nanosheets and SPEEK matrix. So, SPEEK/GO-BDSA hybrid membranes demonstrate a promising prospect for VRFB as the proton exchange membrane.

中文翻译：

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两性氧化石墨烯纳米片的磺化聚醚醚酮杂化膜作为钒还原液流电池的界面增强剂

磺化聚醚醚酮（SPEEK）杂化膜是通过掺入2,2'-联苯胺二磺酸官能化的两性氧化石墨烯（GO-BDSA）纳米片制备的。就形成的界面作用而言，优化的膜渗透性和离子选择性极大地调节了钒流氧化还原电池（VRFB）的性能。在GO-BDSA纳米片的1 wt％负载下，SPEEK / GO-BDSA-1的质子传导率和离子选择性达到最大值，例如30.7 mS cm ^–1和43.3×10 ³ S min cm ^–3， 分别。与SPEEK（38 h）和Nafion 117（33.5 h）的自放电时间相比，SPEEK / GO-BDSA-1混合膜显示了更长的95.3 h。同时，电压效率（VE，92％）和能源效率（EE，85％）分别高于SPEEK（VE，87％和EE，82％）和Nafion 117（VE，89％和EE，84％） ）在50 mA·cm ^–2处确认。经过250次充放电试验，推测SPEEK / GO-BDSA-1杂化膜的结构稳定性和耐久性，归因于GO-BDSA纳米片与SPEEK基质的相互作用。因此，SPEEK / GO-BDSA杂化膜证明了VRFB作为质子交换膜的广阔前景。