The concentration gradient battery (CGB) has numerous advantages, such as zero pollution emissions and the use of non-toxic electrolytes, making it a promising candidate for integrating renewable energy into the power grid. The use of high-performance membranes is a necessary condition for the application of CGB, but the specific membrane characteristics that contribute to desired CGB performance have not been clearly defined. In this study, five commercial membranes were employed to investigate the relationship among membrane permeation of water and salt, stack resistance, and battery performance. The results highlighted the pivotal roles of membrane permeability and resistivity in determining the CGB performance. Among the membrane tested, Selemion, notable for its low permeability and resistivity, was found to effectively break the trade-off between current and voltage efficiency. This superior performance is attributed to its distinctive membrane properties of low water volume fraction and high fixed charge density. This study further suggested that strategies aimed at controlling membrane swelling and increasing fixed charge density hold great promise in enhancing the membrane performance in CGB application. This research provides insights into membrane selection and customization for CGB and serves as a reference for other membrane processes focused on energy conversion.

中文翻译：

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揭示膜特性在水和盐传输中的作用以及浓度梯度电池的性能

浓度梯度电池（CGB）具有零污染排放和使用无毒电解质等众多优点，使其成为将可再生能源并入电网的有希望的候选者。使用高性能膜是CGB应用的必要条件，但有助于实现所需CGB性能的具体膜特性尚未明确定义。在这项研究中，采用了五种商用膜来研究膜的水和盐渗透性、电池组电阻和电池性能之间的关系。结果强调了膜渗透性和电阻率在决定 CGB 性能方面的关键作用。在测试的膜中，Selemion 以其低渗透性和电阻率而闻名，被发现可以有效打破电流和电压效率之间的权衡。这种优越的性能归因于其独特的膜特性，即低水体积分数和高固定电荷密度。这项研究进一步表明，旨在控制膜膨胀和增加固定电荷密度的策略对于增强 CGB 应用中的膜性能具有广阔的前景。这项研究为 CGB 的膜选择和定制提供了见解，并为其他专注于能量转换的膜工艺提供了参考。