Proton Conductive Metal-Organic Frameworks

Abstract

Proton-conductive electrolytes are key materials in fuel cells. We introduced acidic functional groups into a porous coordination polymer (PCP), or metalorganic framework (MOF), and constructed proton-conductive PCP/MOFs. To achieve this, a novel synthetic method for introducing acidic groups in PCP/ MOF was invented. The proton conductivities of various PCP/ MOF materials were investigated by AC impedance spectroscopy, and some of the materials showed high proton conductivity up to 8 © 10¹3Scm¹1 at ambient temperature.We also investigated the dependency of proton conductivity on functional groups and found a relationship between proton conductivity, the acidity of the functional groups, and the hydrogen- bond networks formed inside the pores of PCP/MOFs. These PCP/MOF materials have high crystallinity, and the frameworks and arrangement of guests in the inner pore were clearly determined by X-ray crystallographic analysis. The relationship between proton conductivity and hydrogen-bond networks was investigated. This study thus establishes a novel field for investigating highly proton-conductive materials.