Construction and Investigation of Novel Cross-Linked Fluorine-Containing Sulfonated Polyimide Membranes for VFB Application

Autor: Long, Jun, Huang, Wenheng, Li, Huiting, Chen, Liang, Li, Jinchao, Chen, Jijun, Lu, Aibing, Zhang, Yaping
Zdroj: ACS Applied Materials & Interfaces; June 2024, Vol. 16 Issue: 25 p32611-32618, 8p
Abstrakt: 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 cm2), lower vanadium ion permeability (0.76 × 10–7cm2min–1), and remarkable proton selectivity (3.11 × 105min cm–3) 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–2are 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.
Databáze: Supplemental Index