在性固体聚合物电解质薄膜中电化学减少溶解氧
David Novitski1, Aslan Kosakian2, Thomas Weissbach1
1Department of Chemistry, Simon Fraser University , Burnaby, British Columbia V5A 1S6, Canada.
Journal of the American Chemical Society
|November 3, 2016
概括
离子交换膜燃料电池中的氧气运输至关重要,但研究不足. 降低离子体含水量显著减少氧气扩散,影响燃料电池的性能.
科学领域:
- 电化学
- 材料科学
- 化学工程
背景情况:
- 通过离子体运输氧气对于离子交换膜燃料电池 (AEMFC) 来说至关重要.
- 水是性介质中氧降解反应 (ORR) 的反应剂,需要足够的水供应.
- 阴极催化剂层的质量传输限制是AEMFC性能的一个关键挑战.
研究的目的:
- 在AEMFC离子体中研究氧降解反应 (ORR) 质量传输行为.
- 确定离子体含水量对氧气扩散和度的影响.
- 在薄离子膜中评估Shoup-Szabo方程的精度.
主要方法:
- 使用Pt微盘电极的电化学电位步骤时计.
- 测试甲基化六甲基-p-聚甲基胺醇 (HMT-PMBI) 和Fumatec FAA-3膜.
- 在60°C控制相对湿度为70%至98%.
- 使用Shoup-Szabo方程式的电流瞬态的非线性曲线.
- 数值建模以评估Shoup-Szabo方程的局限性.
主要成果:
- 随着相对湿度 (含水量) 的下降,氧气扩散系数 (DbO2) 降低了两倍.
- 发现氧气透性 (DbO2·cbO2) 强烈依赖于离子体中的水含量.
- 使用Shoup-Szabo方程式的数值模型显示高达29%的差异.
结论:
- 离子体中的水含量对AEMFC中的氧质运输有显著影响.
- 减少含水量会导致氧气扩散的大幅减少,可能会限制ORR.
- 由于接口效应,Shoup-Szabo方程式可能会高估高度水合膜的质量传输参数.
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