Long Jun, Huang Wenheng, Li Huiting, Chen Liang, Li Jinchao, Chen Jijun, Lu Aibing, Zhang Yaping
State Key Laboratory of Environment-friendly Energy Materials, Engineering Research Center of Biomass Materials (Ministry of Education), and School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, PR China.
Sichuan Weilide Energy Co., Ltd, Leshan 614000, PR China.
ACS Appl Mater Interfaces. 2024 Jun 26;16(25):32611-32618. doi: 10.1021/acsami.4c03314. Epub 2024 Jun 12.
Membrane with remarkable proton conductance and selectivity plays a key role in obtaining high vanadium flow battery (VFB) performance. In this work, the trade-off effect between proton conductance and vanadium ion blocking was overcome by the introduction of a cross-linking structure to prepare covalent cross-linked fluorine-containing sulfonated polyimide (CFSPI-PVA) membranes. Herein, the CFSPI-PVA-15 membrane possesses excellent comprehensive properties, including acceptable area resistance (0.21 Ω cm), lower vanadium ion permeability (0.76 × 10 cm min), and remarkable proton selectivity (3.11 × 10 min cm) compared with the commercial Nafion 212 membrane. At the same time, the CFSPI-PVA-15 membrane exhibits higher coulomb efficiencies (97.26%-99.34%) and energy efficiencies (68.65%-88.11%) and a longer self-discharge duration (29.2 h) in contrast with the Nafion 212 membrane. Moreover, 500 cycles of the CFSPI-PVA-15 membrane at 160 mA cm are also stably executed. The internal reasons for the improved chemical stability of the CFSPI-PVA-15 membrane are clarified from theoretical calculations with the mean square displacement value and fractional free volume. Therefore, the CFSPI-PVA-15 membrane exhibits great potential for application in VFB.
具有卓越质子传导率和选择性的膜在获得高性能全钒液流电池（VFB）方面起着关键作用。在这项工作中，通过引入交联结构来制备共价交联含氟磺化聚酰亚胺（CFSPI - PVA）膜，克服了质子传导率与钒离子阻隔之间的权衡效应。在此，与商业Nafion 212膜相比，CFSPI - PVA - 15膜具有优异的综合性能，包括可接受的面积电阻（0.21Ω·cm）、较低的钒离子渗透率（0.76×10⁻⁷cm²/min）以及显著的质子选择性（3.11×10³min⁻¹·cm²）。同时，与Nafion 212膜相比，CFSPI - PVA - 15膜表现出更高的库仑效率（97.26% - 99.34%）和能量效率（68.65% - 88.11%）以及更长的自放电持续时间（29.2小时）。此外，CFSPI - PVA - 15膜在160mA/cm²下也能稳定地进行500次循环。通过均方位移值和分数自由体积的理论计算，阐明了CFSPI - PVA - 15膜化学稳定性提高的内在原因。因此，CFSPI - PVA - 15膜在全钒液流电池中具有巨大的应用潜力。
