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Three-Dimensional Protonic Conductivity in Porous Organic Cage Solids



Ming Liu, Linjiang Chen, Scott Lewis, Samantha Y. Chong, Marc A. Little, Tom Hasell, Iain M. Aldous, Craig Brown, Martin W. Smith, Carole A. Morrison, Laurence J. Hardwick, Andrew I. Cooper


Proton conduction is a fundamental process in biology and in devices such as proton exchange membrane fuel cells. To maximize proton conduction, 3-D conduction pathways are preferred over 1-D pathways, which prevent proton conduction in two-dimensions. Many crystalline porous solids o date show 1-D proton conduction. Here we report porous molecular cages with proton conductivities (up to 10^-3^ S cm-1 at high relative humidity) that compete with extended metal-organic frameworks. The structure of the organic cage imposes a proton conduction pathway that is necessarily 3-D. The cage molecules also promote proton transfer by confining the water molecules while being sufficiently flexibly to allow hydrogen bond reorganization. The proton conduction is explained at the molecular level through a combination of proton conductivity measurements, crystallography, molecular simulations, and quasi-elastic neutron scattering. These results provide a starting point for high-temperature, anhydrous proton conductors through inclusion of guests other than water in the cage pores.
Nature Communications


quasielastic neutron scattering, porous cages, diffusion, water


Liu, M. , Chen, L. , Lewis, S. , Chong, S. , Little, M. , Hasell, T. , Aldous, I. , Brown, C. , Smith, M. , Morrison, C. , Hardwick, L. and Cooper, A. (2016), Three-Dimensional Protonic Conductivity in Porous Organic Cage Solids, Nature Communications, [online], (Accessed July 20, 2024)


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Created September 12, 2016, Updated October 12, 2021