A Metal–Organic Framework with Tetrahedral Aluminate Sites as a Single‐Ion Li+ Solid Electrolyte

Abstract We demonstrate the synthesis of the first anionic aluminum metal–organic framework (MOFs) constructed from tetrahedral AlO 4 sites. Al‐Td‐MOF‐1 was obtained in a simple two‐step synthesis by condensation of 1,4‐dihydroxybenzene and lithium aluminum hydride into an amorphous aluminate framework before applying a solvothermal treatment under basic conditions to obtain the crystalline Al‐Td‐MOF‐1 with a chemical composition of Li[Al(C 6 H 4 O 2 ) 2 ]. The overall Al‐Td‐MOF‐1 structure consists of one‐dimensional chains of alternating edge‐sharing AlO 4 and LiO 4 tetrahedral sites describing unidirectional pore channels with a square window aperture of ≈5×5 Å 2 , best described topologically as a uninodal 6‐coordinated snp rod net. Al‐Td‐MOF‐1 features the highest Li + loading reported to date for a MOF (2.50 wt %) and proved to be an effective single‐ion solid electrolyte. An ionic conductivity of 5.7×10 −5 S cm −1 was measured for Al‐Td‐MOF‐1 and the beneficial contribution of crystallinity was evidenced by an 8‐fold increase in conductivity between the disordered and crystalline material.