2D Crystals Significantly Enhance the Performance of a Working Fuel Cell
2D Crystals Significantly Enhance the Performance of a Working Fuel Cell
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DOI：
10.1002/aenm.201601216
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发表时间：
2017-03-08
影响因子：
27.8
通讯作者：
Nair, Rahul R.
中科院分区：
文献类型：
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作者：
Holmes, Stuart M.;Balakrishnan, Prabhuraj;Nair, Rahul R.
2D原子晶体如单层石墨烯（SLG）和六方氮化硼（hBN）已经被证明在环境条件下对氢离子具有“出乎意料的渗透性”，质子电导率随温度呈指数上升。这里，通过化学气相沉积（CVD）方法制备的SLG的第一次成功添加被示出为操作的直接甲醇燃料电池，一旦温度升高到60摄氏度以上，SLG的质子传导率高于其安装在其上的Nafion膜的温度，则显著增强电池的性能。在此温度以上，系统的质子传输阻力不受石墨烯的影响，但石墨烯的屏障特性抑制甲醇渗透。示出的燃料电池的性能，以线性增加与覆盖的SLG在此温度以上。结果表明，与不含石墨烯的标准膜电极组件相比，最大功率密度在70 ℃下增加了45%。此外，具有CVD hBN的膜由于在较低温度下更好的质子传导性而在整个温度范围内显示出增强的性能。
2D atomic crystals such as single layer graphene (SLG) and hexagonal boron nitride (hBN) have been shown to be "unexpectedly permeable" to hydrogen ions under ambient conditions with the proton conductivity rising exponentially with temperature. Here, the first successful addition of SLG made by a chemical vapor deposition (CVD) method is shown to an operational direct methanol fuel cell significantly enhancing the performance of the cell once the temperature is raised above 60 degrees C, the temperature at which the proton conductivity of SLG is higher than the Nafion membrane on which it is mounted. Above this temperature, the resistance to proton transport of the system is not affected by the graphene but the barrier properties of graphene inhibit methanol crossover. The performance of the fuel cell is shown to increase linearly with coverage of SLG above this temperature. Results show that the maximum power density is increased at 70 degrees C by 45% in comparison to the standard membrane electrode assembly without graphene. In addition, a membrane with CVD hBN shows enhanced performance across the entire temperature range due to better proton conductivity at lower temperatures.