Ionic Conduction Mechanism and Design of Metal-Organic Framework Based Quasi-Solid-State Electrolytes

We report the theoretical and experimental investigation of two polyoxometalate-based metal-organic frameworks (MOFs), [(MnMo6)(2)(TFPM)] imine and [(AlMo6)(2)(TFPM)](imine), as quasi-solid-state electrolytes. Classical molecular dynamics coupled with quantum chemistry and grand canonical Monte Carlo are utilized to model the corresponding diffusion and ionic conduction in the two materials. Using different approximate levels of ion diffusion behavior, the primary ionic conduction mechanism was identified as solvent-assisted hopping (>77%). Detailed static and dynamic solvation structures were obtained to interpret Li+ motion with high spatial and temporal resolution. A rationally designed noninterpenetrating MOF-688(one-fold) material is proposed to achieve 6-8 times better performance (1.6-1.7 mS cm(-1)) than the current state-of-the-art (0.19-0.35 mS cm(-1)).

Automated summary

This study investigates the potential of two polyoxometalate-based metal-organic frameworks as quasi-solid-state electrolytes through theoretical and experimental methods. By simulating diffusion and ionic conduction processes, the primary ionic conduction mechanism is identified and the solvation structure of Li+ motion is obtained. Additionally, a noninterpenetrating material with improved performance is proposed.