Fast proton and water transport in ceramic membrane-based magic-angle graphene.

Ceramic membranes for energy conversion and storage devices are essential for becoming carbon neutral due to low cost and high stability, but limited by slow proton and water transport. Meanwhile magic-angle graphene with unconventional superconductivity ushers in a new era, properties research of which are in infant stage, urgently longing for specific applications. Herein, we investigate the ionic-conductivity and water-transport properties of ceramic membrane-based magic-angle graphene by choosing proton and water as a proof-of-concept for the first time, discover the twist-angle tuned proton conduction and water transport in ceramic membrane-based magic-angle graphene, demonstrate the faster proton and water transport in magic-angle graphene than that in graphene, and construct an efficient device of protonic ceramic membrane fuel cell based upon the new fast proton-conducting materials of magic-angle graphene. The proton conduction and water transport in magic-angle graphene can be easily tuned by the twist angle, explained by the corresponding potential energy surface. The smaller the twist angle is, and the faster the proton transport is. The protonic migration energy barrier in magic-angle graphene is lower by about 50% than that in graphene. Additionally, the water transport properties in magic-angle graphene can be improved by tuning twist angles. The electrode with magic-angle graphene can provide higher performance of protonic ceramic membrane fuel cells. The present work opens the specific application of ceramic membrane-based magic-angle graphene as new proton-conducting and water-transport materials in energy and environment.