Effects of Base Strength and Coordinating Solvent on Semiconducting MOF Formation

Conductive metal-organic frameworks (MOFs) hold great promise for many electrochemical applications, including lithium-sulfur (Li-S) battery technology due to their crystallinity, semiconductive nature, and tunable metal chemistry. In this work, through altering the base strength and coordinating solvents, we have found that slowing the crystal formation for M₃(HITP)₂ (M = Ni, Cu) MOFs produces more crystalline MOFs with desirable pore size that can be integrated into a Li-S battery cathode to prevent lithium-polysulfide (Li-PS) shuttling. When implementing a weaker base and a coordinating solvent, activation energy (Ea) values for Ni₃(HITP)₂ changed from 7.88x10-5 eV to 6.86x10-5 eV. For Cu₃(HITP)₂, the Ea was found to be 4.85x10-5eV. For Ni₃(HITP)₂, the pore size decreased from 3.6 nm to 2.9 nm. For Cu₃(HITP)₂, the pore diameter was 11.6 nm. For Ni₃(HITP)₂ and Cu₃(HITP)₂, the conductivities were found to be 0.32l S/cm and 1.17x10-4 S/cm, respectively.