Recently, the team of Professor Zhang Ning and Professor Zhu Guangshan of the School of Chemistry of NENU makes new progress in the field of covalent organic framework membrane. This research first adopted the strategy of surface-initiated polymerization, which can control the ultrathin free-standing COF membrane for high-efficiency proton conduction. Titled “Surface-Mediated Construction of Ultrathin Free-standing Covalent Organic Framework Membrane for Efficient Proton Conduction”, the study is published on the internationally renowned journal- Angewandte Chemie International Edition (Impact Factor: 12.96).
In recent years, proton exchange membrane fuel cells have been widely used in aerospace, rail transit and new energy vehicles. As the core component of the fuel cell, the development of a new type of proton exchange membrane has become a a topic of currency. Covalent organic framework (COF) materials are a new type of organic porous crystalline materials. Because of their regular pores and clear chemical structure, they have attracted widespread attention in the field of proton conduction. However, COF is mostly power that is insoluble and difficult to process, which limits its application in proton exchange membrane fuel cells. At present, most studies have been reported to improve the proton conductivity of COF materials by producing mixed matrix membranes or incorporating small acidic molecules. However, the compatibility between the polymer and the COF particles is usually very poor, leading to agglomeration of the particles and reducing the performance of the membrane. Moreover, in the method of incorporating small molecules, the distribution of small acid molecules and COF particles in the polymer in the pore channel cannot be accurately controlled.
In response to the above problems, the team of Professor Zhang Ning and Professor Zhu Guangshan proposed a surface-initiated polymerization method to produce an ultrathin free-standing COF membrane. Because the prepared COF membrane has an ordered rigid framework and abundant sulfonic acid groups, it has outstanding advantages in terms of proton conductivity. At 30°C, the conductivity of the COF membrane can reach 0.20 S cm-1. After 40 hours of continuous measurement at 80°C, the conductivity does not decrease and can be stabilized at 0.54 S cm-1. This performance is much higher than commercial Nafion membrane. This research may provide a new preparation method for the preparation of COF in the field of proton exchange membranes, and is expected to become a new generation of high-performance COF membrane preparation technology.
The first author of this article is Liu Lin, a PhD student in the School of Chemistry, and the corresponding authors are Professor Zhang Ning and Professor Zhu Guangshan, teachers of the School of Chemistry.
Original link: https://onlinelibrary.wiley.com/doi/10.1002/anie.202104106
(From News Center, translated by Wei Jia, revised by Liu Lixin)