本文要点：
纳米流体膜的进步对于模拟生物电离子通道机制和提高输出功率密度至关重要，这对可持续能源应用至关重要。这些装置的能量转换效率很大程度上依赖于膜的离子传导性和渗透选择性。理论上，具有对齐的一维(1D)孔、高孔密度和有序的悬挂离子基团的膜提供了优异的离子渗透性和选择性，然而这些构型仍未被充分探索。
本文介绍了定向离子共价有机骨架(COF)膜的成功制备。这些膜在其孔道内显示出精确排列的阳离子和阴离子位点，这是通过使用点击化学的合成后改性实现的，其显示出高的离子选择性和导电性。
当结合到全电池热渗透发生器中时，这些膜在50倍盐度梯度(NaCl: 0.01 m ‖ 0.5 m ‖ 0.01 m) 以及35 K温差下提供令人印象深刻的195 W m−2的输出功率密度。
当盐度梯度增加10倍时，这种功率输出大幅增加2.41倍，达到471 W m-2，超过了类似条件下现有纳米流体膜的性能，从而为提高能源和资源利用效率提供了一种有前途的途径。
Figure 1. Schematic representation of membranes engineered to enhance ion flux and selectivity in high electrolyte environments. a) Ionic membrane with disordered pore structures. b) Ionic membrane featuring ordered 1D straight channels, implanted with end-tethered ionic sites. c) Ionic membrane with similar channels, decorated with dangling ionic sites that introduce space charge and increase the coverage of electric double layers (EDLs, cyan area), thereby improving performance.
Figure 2. Synthesis and characterization of membranes. a) Schematic illustration of the synthesis process for the COF-TAPB-BPTA membrane via liquidsolid interfacial condensation between TAPB and BPTA, catalyzed by Sc(OTf)3, along with the synthesis of the COF-COOH-x and COF-QA-x membranes through a click reaction. b) Oblique-view SEM image of the COF-TAPB-BPTA membrane, with an inset showing the cross-sectional view. c–e) TEM images of the COF-TAPB-BPTA membrane, including an inset in panel c displaying the SAED pattern (top left corner) and a high-resolution image (bottom left corner). The average intensity profiles for the selected areas d1 and d2 are shown in panels c and d. f–h) PXRD pattern, GIWAXS pattern, and N2 sorption isotherms of the COF-TAPB-BPTA membrane, with an inset depicting the pore size distribution determined using non-local density functional theory.
Figure 3. Characterization of membranes after post-synthetic modification. a) Solid-state 13C NMR spectra of the COF-TAPB-BPTA, COF-COOH-6 h, and COF-QA-6 h membranes. b) 2D GIWAXS pattern of COF-COOH-6 h with its corresponding 1D projection. c) 2D GIWAXS pattern of COF-QA-6 h with its corresponding 1D projection.
Figure 4. Investigation of transmembrane ion behavior.
Figure 5. Performance evaluation of the thermo-osmotic battery.
Figure 6. Comparison of output power density between this work and previously reported systems based on reticular framework materials, tested under a NaCl concentration gradient of 50 (0.01 m ‖ 0.5 m). The numbers in the upper-right corner of each membrane refer to the corresponding references in the Supporting Information.
https://doi.org/10.1002/aenm.202405045
