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.A l-Td-MOF-1 was obtained in as imple two-step synthesis by condensation of 1,4-dihydroxybenzene and lithium aluminum hydride into an amorphous aluminate framework before applying as olvothermal treatment under basic conditions to obtain the crystalline Al-Td-MOF-1 with achemical 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 as quare window aperture of % 5 5 2 ,best described topologically as auninodal 6-coordinated snp rod net. Al-Td-MOF-1 features the highest Li + loading reported to date for aMOF (2.50 wt %) and proved to be an effective single-ion solid electrolyte.A n ionic conductivity of 5.7 10 À5 Scm À1 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.

Covalent Organic Frameworks: Design, Synthesis, and Functions

“…At room temperature, the conductivity is 2.7 × 10 –5 S cm –1 without any addition of Li salts or organic solvents, and the E a value is 0.18 eV. Notably, this conductivity is compatible with those of propylene carbonate (PC) solvent-containing ion conductors based on the anionic COF composite (3.05 × 10 –5 S cm –1 ) and MOF composite (5.7 × 10 –5 S cm –1 ) . Another similar method to immobilize ions in the Li-ImCOFs (Figure B) is to diffuse Li + ion through the channels owing to the interaction between Li + and imidazole .…”

“…Notably, this conductivity is compatible with those of propylene carbonate (PC) solvent-containing ion conductors based on the anionic COF composite (3.05 × 10 −5 S cm −1 ) 217 and MOF composite (5.7 × 10 −5 S cm −1 ). 463 Another similar method to immobilize ions in the Li-ImCOFs (Figure 79B) is to diffuse Li + ion through the channels owing to the interaction between Li + and imidazole. 263 Interestingly, the electronwithdrawing substituent weakens the ion-pair interaction and improves the conductivity.…”