Developing a Unique Hydrogen-Bond Network in a Uranyl Coordination Framework for Fuel Cell Applications
Daxiang Gui, Yugang Zhang, Hui Li, Jie Shu, Lanhua Chen, Ling Zhao, Juan Diwu, Zhifang Chai, Shuao Wang
Abstract
Crystalline materials with persistent high anhydrous proton conductivity that can be directly used as a practical electrolyte of the intermediate-temperature proton exchange membrane fuel cells for durable power generation remain a substantial challenge. The present work proposes a unique way of the axial uranyl oxo atoms as hydrogen-bond acceptors to form a dense hydrogen-bonded network within a stable uranyl-based coordination polymer, UO2(H2PO3)2(C3N2H4)2 (HUP-3). It exhibits stable and efficient anhydrous proton conductivity over a super-wide temperature range (−40–170 °C). It was also assembled into a H2/O2 fuel cell as the electrolyte and shows a high electrical power density of 11.8 mW·cm–2 at 170 °C, which is among one of the highest values reported from crystalline solid electrolytes. The cell was tested for over 12 h without notable power loss.