Multiscale Architectured Nafion Membrane Derived from Lotus Leaf for Fuel Cell Applications
Yali Li, Qinglin Wen, Siyi Zou, Xiong Dan, Fandi Ning, Wei Li, Pengpeng Xu, Can He, Min Shen, Lei He, Bin Tian, Xiaochun Zhou
Abstract
Hierarchically patterned proton-exchange membranes (PEMs) have the potential to significantly increase the specific surface area, thus improving the catalyst utilization rate and performance of proton-exchange membrane fuel cells (PEMFCs). In this study, we are inspired by the unique hierarchical structure of the lotus leaf and proposed a simple three-step strategy to prepare a multiscale structured PEM. Using the multilevel structure of the natural lotus leaf as the original template, and after structural imprinting, hot-pressing, and plasma-etching steps, we successfully constructed a multiscale structured PEM with a microscale pillar-like structure and a nanoscale needle-like structure. When applied in a fuel cell, the multiscale structured PEM resulted in a 1.96-fold increase in discharge performance and a significant improvement in mass transfer compared to the membrane electrode assembly (MEA) with a flat PEM. The multiscale structured PEM has the combined advantage of a nanoscale and a microscale structure, benefiting from the markedly reduced thickness, increased surface area, and improved water management inherited from the multiscale structured lotus leaf's superhydrophobic characteristic. Using a lotus leaf as a multilevel structure template avoids the complex and time-consuming preparation process required by commonly used multilevel structure templates. Moreover, the remarkable architecture of biological materials can inspire novel and innovative applications in many fields through nature's wisdom.