在共价有机框架膜中操纵阴离子群密度以实现有效的离子传输
Yan Kong1,2, Bohui Lyu3,4, Chunyang Fan1,2
1Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
Journal of the American Chemical Society
|December 15, 2023
概括
新的共价有机框架 (COF) 膜为电化学应用提供高离子导电性和维度稳定性. 灵活的侧链和可调节的四级组密度优化离子传输,实现创纪录的导率.
科学领域:
- 材料科学
- 电化学
- 聚合物化学
背景情况:
- 高离子导电性对于电化学装置至关重要,但提高它往往会损害膜稳定性.
- 同价有机框架 (COF) 为离子传输提供了有序结构,但在没有稳定性损失的情况下实现高功能群密度是具有挑战性的.
研究的目的:
- 设计和合成具有可调节四级组密度的新型同轴COF膜,用于离子导电.
- 研究COF膜中的离子群密度,侧链灵活性和离子导电性之间的关系.
- 在离子交换膜中同时实现高离子交换能力和异常的尺寸稳定性.
主要方法:
- 通过灵活的以太结合侧链合成具有不同四级群密度的三种异构COF膜.
- 膜特性,包括离子交换能力,维度稳定性和离子导电性.
- 结合实验和模拟方法来阐明离子传输机制和结构参数的影响.
主要成果:
- COF膜具有较高的离子交换能力和优异的尺寸稳定性.
- 灵活的侧链有效地减轻了静电排斥和固体阻碍,促进了紧密的层间堆叠.
- 发现离子导电性是由离子组度和侧链流动性共同决定的,而不是仅由组密度决定的.
- 最佳的COF膜在80°C和100%的相对湿度下实现了超过300mS cm-1的氧离子导电率.
结论:
- 具有灵活侧链和可控功能化的COF膜的合理设计是实现高性能的关键.
- 这项研究揭示了离子群密度和离子导电性之间的异常相关性,强调了侧链流动性的重要性.
- 这些发现为开发电化学应用先进的离子交换膜提供了有价值的指导方针.
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