ABSTRACT

A novel membrane-electrode structure is conceived and prepared in this work, where a graphene-contained layer is constructed between anode catalyst layer and membrane, also the material composition in this layer is optimized to improve the performance of a direct methanol fuel cell (DMFC) with high-concentration fuel. The polarization test shows that the pristine graphene layer could reduce the methanol crossover, while causing a slight decrease in performance. After adding Nafion ionomer binder in the graphene layer, the peak power density of the electrode fed with 8 M methanol reaches 17.75 mW cm⁻², which is increased by 12.36% and 82.69% compared with the conventional electrode and the electrode without any binder in the graphene layer, respectively. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) results show that for the graphene-contained layer including Nafion ionomer binder, the charge transfer resistance is only one-fifth of that without binder in the graphene layer, and the anode electrochemical active surface area (ECSA) is increased by 40.16%. These results indicate that the anode electrode with a graphene-contained layer using Nafion ionomer as the binder can effectively improve the cell performance with high-concentration fuel, which is beneficial to increase the energy density of a DMFC system.

摘要

在这项工作中，构思并制备了一种新型的膜电极结构，其中在阳极催化剂层和膜之间构建了一个含石墨烯的层，并且对该层中的材料成分进行了优化，以改善直接甲醇燃料电池（DMFC）的性能。 ）和高浓度燃料。极化测试表明，原始石墨烯层可以减少甲醇的渗透，同时导致性能略有下降。在石墨烯层中添加Nafion离聚物粘合剂后，喂入8 M甲醇的电极的峰值功率密度达到17.75 mW cm ^-2与常规电极和在石墨烯层中没有任何粘合剂的电极相比，其分别增加了12.36％和82.69％。电化学阻抗谱（EIS）和循环伏安法（CV）结果表明，对于包含Nafion离聚物粘合剂的含石墨烯的层，其电荷转移电阻仅为石墨烯层中无粘合剂和阳极电化学活性表面的五分之一面积（ECSA）增加了40.16％。这些结果表明，使用Nafion离聚物作为粘合剂的具有石墨烯包含层的阳极电极可以有效地改善高浓度燃料的电池性能，这有利于增加DMFC系统的能量密度。