Department of Chemistry, College of Sciences, Northeastern University, Shenyang, 110004, China.
Department of Chemistry, Lund University, Lund, SE-221, Sweden.
Macromol Rapid Commun. 2024 Nov;45(22):e2400477. doi: 10.1002/marc.202400477. Epub 2024 Sep 10.
Vanadium redox flow batteries (VRFBs) depend on the separator membrane for their efficiency and cycle life. Herein, two amphoteric ion exchange membranes are synthesized, based on sulfonic acid group-grafted poly(p-terphenyl piperidinium), for VRFBs. Using ether-free poly(p-terphenyl piperidine) (PTP) as the polymer matrix, and sodium 2-bromoethanesulphonate (ES) and 1,4-butane sultone (BS) as grafting agents, We achieve quaternization of PTP through an environmentally friendly process without alkaline catalysts. PTP-ES and PTP-BS membranes exhibit low area resistance, high H permeability, and significantly reduced vanadium ion permeability, leading to exceptional ion selectivity, which is 3.06 × 10 S min cm and 4.34 × 10 S min cm, respectively, three orders of magnitude higher than that of Nafion115 (0.27 × 10 S min cm). The VRFB with PTP-BS achieves a self-discharge duration of 190 h, compared to 86 h for Nafion 115. Additionally, under current densities of 40-160 mA cm, PTP-BS shows coulombic efficiencies of 98.1-99.1% and energy efficiencies of 92.0-82.1%, outperforming Nafion 115. The VRFB with PTP-BS also demonstrates excellent cycle stability and discharge capacity retention over 300 cycles at 100 mA cm. Therefore, the amphoteric PTP-BS membrane shows remarkable performance, offering significant potential for VRFB applications.
钒氧化还原流电池 (VRFB) 的效率和循环寿命取决于其分离膜。本文基于磺化基团接枝聚对三联苯哌啶（PTP），合成了两种两性离子交换膜，用于 VRFB。我们使用无醚的聚对三联苯哌啶（PTP）作为聚合物基质，以 2-溴乙磺酸钠（ES）和 1,4-丁烷砜（BS）作为接枝剂，通过无碱性催化剂的环保工艺实现 PTP 的季铵化。PTP-ES 和 PTP-BS 膜具有低面电阻、高 H 渗透率和显著降低的钒离子渗透率，从而表现出出色的离子选择性，分别为 3.06×10 S min cm 和 4.34×10 S min cm，比 Nafion115（0.27×10 S min cm）高三个数量级。与 Nafion 115 的 86 h 相比，使用 PTP-BS 的 VRFB 的自放电持续时间达到 190 h。此外，在 40-160 mA cm 的电流密度下，PTP-BS 的库仑效率为 98.1-99.1%，能量效率为 92.0-82.1%，优于 Nafion 115。使用 PTP-BS 的 VRFB 还在 100 mA cm 下经过 300 次循环后表现出出色的循环稳定性和放电容量保持率。因此，两性 PTP-BS 膜表现出卓越的性能，为 VRFB 的应用提供了巨大的潜力。
