Non-aqueous redox flow batteries (RFBs) are a promising technology to meet growing demand for grid-scale energy storage. Membrane separators, designed specifically for use with organic solvents, are necessary to advance non-aqueous RFBs. Herein, we report the development of a series of poly(phenylene oxide) (PPO) membranes functionalized with poly(ethylene glycol) (PEG) side chains to investigate the influence of PEG side chain length and degree of PEGylation on membrane transport properties. Increasing the degree of PEGylation generally led to increases in electrolyte uptake, hydroxy TEMPO permeability, and ionic conductivity likely caused by an increase in overall PEG content, as opposed to specific interactions caused by changing the degree of PEGylation. For membranes with similar PEG content, increasing the length of the PEG side chain resulted in decreases in electrolyte uptake, permeability, and conductivity possibly due to differences in the solvation behavior of the PEG chains with different lengths.

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暴露于非水电解质的乙二醇功能化膜的传输特性

非水氧化还原液流电池（RFB）是一种很有前途的技术，可以满足电网规模储能不断增长的需求。专门设计用于有机溶剂的膜分离器对于推进非水性 RFB 是必要的。在此，我们报告了一系列用聚乙二醇（PEG）侧链功能化的聚苯醚（PPO）膜的开发，以研究 PEG 侧链长度和聚乙二醇化程度对膜传输特性的影响。增加聚乙二醇化程度通常会导致电解质吸收、羟基 TEMPO 渗透性和离子电导率的增加，这可能是由总 PEG 含量的增加引起的，而不是通过改变聚乙二醇化程度引起的特定相互作用。对于具有相似 PEG 含量的膜，增加 PEG 侧链的长度会导致电解质吸收、渗透性和电导率降低，这可能是由于不同长度的 PEG 链的溶剂化行为存在差异。