Nanoscale solid superacid SO₄^2–/ZrO₂/WO₃ is coupled into imidazole-hydroxyl-quaternary ammonium co-functionalized polybenzimidazole (PG112) to address the trade-off effect of membrane for large-scale flow battery application. Nanoscale SO₄^2–/ZrO₂/WO₃ particles with high sulfonic groups are dispersed in membrane as redox-active ion barriers and proton carriers, which mitigate the electrolyte crossover and maintain high ion conductivity. The VO²⁺ permeability of the prepared membrane (7.86 × 10^–10 cm² s^–1) is significantly lower than those of PG112 (3.93 × 10^–9 cm² s^–1) and Nafion 212 (7.76 × 10^–8 cm² s^–1) membranes. The vanadium flow battery with this membrane exhibits a longer self-discharge duration time of 231 h compared with Nafion 212 (35 h) and PG112 (88 h) membranes. High coulombic efficiencies of 97.5–99.2% at 40–120 mA cm^–2 are obtained for the prepared membrane, which are higher than those for Nafion 212 (78.0–92.8%) and PG112 membranes (96.2–98.6%). Stable cycle performance and low retention capacity are also observed, suggesting the excellent chemical stability of the prepared membrane in vanadium flow battery operation. This work provides a prospective and applicable membrane to enhance the performance of flow battery.

中文翻译：

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纳米级固体超酸偶联的聚苯并咪唑膜对流动电池具有高离子选择性

将纳米级固体超强酸SO ₄ ^2- / ZrO ₂ / WO ₃偶联到咪唑-羟基-季铵共官能化聚苯并咪唑（PG112）中，以解决膜在大规模液流电池应用中的权衡效果。具有高磺酸基的纳米级SO ₄ ^2- / ZrO ₂ / WO ₃颗粒作为氧化还原活性离子屏障和质子载体分散在膜中，从而减轻了电解质的渗透并保持了高离子电导率。制备的膜的VO ²⁺渗透性（7.86×10 ^–10 cm ² s ^–1）显着低于PG112（3.93×10 ^–9 cm ² s ^–1）和Nafion 212（7.76×10 ^–8 cm ² s ^–1）膜。与Nafion 212（35 h）和PG112（88 h）膜相比，带有该膜的钒液流电池具有更长的自放电持续时间231 h。40–120 mA cm ^–2时的高库仑效率为97.5–99.2％制备的膜的N-离子比Nafion 212（78.0-92.8％）和PG112膜（96.2-98.6％）更高。还观察到稳定的循环性能和低的保留容量，表明所制备的膜在钒液流电池操作中具有优异的化学稳定性。这项工作为提高液流电池的性能提供了一种可应用的前瞻性膜。