A series of solid magnesium electrolytes were synthesized via the transmetallation of magnesium phenolates to coordinatively unsaturated metal sites lining the pores of the metal–organic frameworks Mg2(2,5-dioxidobenzene-1,4-dicarboxylate) and Mg2(4,4′-dioxidobiphenyl-3,3′-dicarboxylate). The resulting materials represent a new class of solid magnesium electrolytes that are both crystalline, and exhibit room-temperature ionic conductivities up to 0.25 mS cm−1. The materials reported herein are one-hundred times more conductive at room temperature than any other solid magnesium electrolyte and represent the only class of materials sufficiently conductive for practical consideration in magnesium batteries.
