Division of Fuel Cell and Battery, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Adv. 2023 Jan 25;9(4):eade1194. doi: 10.1126/sciadv.ade1194.
Ultrahigh mass transport resistance and excessive coverage of the active sites introduced by phosphoric acid (PA) are among the major obstacles that limit the performance of high-temperature polymer fuel cells, especially compared to their low-temperature counterparts. Here, an alternative strategy of electrode design with fibrous networks is developed to optimize the redistribution of acid within the electrode. Via structural tailoring with varied electrospinning parameters, uneven migration of PA with dispersed droplets is observed, subverting the immersion model of conventional porous electrode. Combining with experimental and calculation results, the microscaled uneven PA interfaces could not only provide extra diffusion pathways for oxygen but also minimize the thickness of PA layers. This electrode architecture demonstrates enhanced electrochemical performance of oxygen reduction within the PA phase, resulting in a 28% enhancement of the maximum power density for the optimally designed electrode as cathode compared to that of a conventional one.
在高温聚合物燃料电池中，极高的质量传输阻力和磷酸（PA）对活性位的过度覆盖是限制其性能的主要障碍之一，尤其是与低温聚合物燃料电池相比。在这里，开发了一种具有纤维网络的电极设计的替代策略，以优化电极内酸的再分配。通过改变静电纺丝参数进行结构调整，可以观察到 PA 不均匀的迁移和分散的液滴，颠覆了传统多孔电极的浸渍模型。结合实验和计算结果，微尺度不均匀的 PA 界面不仅可以提供额外的氧扩散途径，还可以最小化 PA 层的厚度。这种电极结构证明了在 PA 相内氧还原的电化学性能得到了增强，与传统的电极相比，优化设计的电极作为阴极的最大功率密度提高了 28%。
