Green synthesis of olefin-linked covalent organic frameworks for hydrogen fuel cell applications
Zhifang Wang, Yi Yang, Zhengfeng Zhao, Penghui Zhang, Yushu Zhang, Jinjin Liu, Shengqian Ma, Peng Cheng, Yao Chen, Zhenjie Zhang
Abstract
Abstract Green synthesis of crystalline porous materials for energy-related applications is of great significance but very challenging. Here, we create a green strategy to fabricate a highly crystalline olefin-linked pyrazine-based covalent organic framework (COF) with high robustness and porosity under solvent-free conditions. The abundant nitrogen sites, high hydrophilicity, and well-defined one-dimensional nanochannels make the resulting COF an ideal platform to confine and stabilize the H 3 PO 4 network in the pores through hydrogen-bonding interactions. The resulting material exhibits low activation energy (E a ) of 0.06 eV, and ultrahigh proton conductivity across a wide relative humidity (10–90 %) and temperature range (25–80 °C). A realistic proton exchange membrane fuel cell using the olefin-linked COF as the solid electrolyte achieve a maximum power of 135 mW cm −2 and a current density of 676 mA cm −2 , which exceeds all reported COF materials.