Synthesis and Characterization of Open-Metal Site Grafting to Metal- Organic Frameworks for Solid Electrolyte Applications

In order for clean energy use to become a significant fraction of global energy use, the energy captured from sources such as wind and solar must be available for consistent use in spite of the daily and seasonal fluctuations in the availability of these resources. Lithium-ion batteries are a promising and prevalent technology for providing this energy storage, but these batteries suffer from degradation modes such as lithium plating and dendrite formation [1] that can shorten the battery’s lifetime and can create significant safety risks, such as battery fires during electric vehicle collisions. The liquid electrolyte in a Li-ion battery contributes significantly to the aforementioned degradation modes, [1] so replacing the liquid with a solid electrolyte can improve both the reliability and safety of energy storage in batteries. Metal-organic frameworks (MOFs) show promise as solid electrolyte materials because of their intrinsic porosity and ion-transport ability. However, the fundamental structure that enables ion transport has not been adequately studied to the extent of being able to optimize the system for ionic conductivity. Here we made progress in understanding how to synthesize and characterize MOFs for potential use in future electrolyte studies. We found that the characterization of the MOF can be impacted by the solvent and additives of synthesis, we learned that the introduction of salt to the MOF for ionic conduction occurs more readily in the absence of water, and we developed a procedure for the growth and characterization of single crystals of MOF-74 for characterization by single-crystal x-ray diffraction (XRD) that allows for full structure solving. These techniques and protocols for MOF characterization that we developed set the stage for a future of MOF solid electrolytes that are designed with their structure-property relationships in mind. Methods for the characterization of MOFs allow for structural information that is integral to their eventual incorporation into batteries as solid electrolytes and their contribution to the energy solution.
Reference:
1. Kyusung Park and John B. Goodenough, Adv. Energy Mater., 2017, 7.

and and . (). Synthesis and Characterization of Open-Metal Site Grafting to Metal-
Organic Frameworks for Solid Electrolyte Applications. Stanford Digital Repository. Available at: https://purl.stanford.edu/pv249rb0607