Li⁺ Dynamics of Liquid Electrolytes Nanoconfined in Metal–Organic Frameworks

High Resolution Image Download MS PowerPoint Slide Metal–organic frameworks (MOFs) are excellent platforms to design hybrid electrolytes for Li batteries with liquid-like transport and stability against lithium dendrites. We report on Li + dynamics in quasi-solid electrolytes consisting in Mg-MOF-74 soaked with LiClO 4 –propylene carbonate (PC) and LiClO 4 –ethylene carbonate (EC)/dimethyl carbonate (DMC) solutions by combining studies of ion conductivity, nuclear magnetic resonance (NMR) characterization, and spin relaxometry. We investigate nanoconfinement of liquid inside MOFs to characterize the adsorption/solvation mechanism at the basis of Li + migration in these materials. NMR supports that the liquid is nanoconfined in framework micropores, strongly interacting with their walls and that the nature of the solvent affects Li + migration in MOFs. Contrary to the “free’’ liquid electrolytes, faster ion dynamics and higher Li + mobility take place in LiClO 4 –PC electrolytes when nanoconfined in MOFs demonstrating superionic conductor behavior (conductivity σ rt > 0.1 mS cm –1, transport number t Li + > 0.7). Such properties, including a more stable Li electrodeposition, make MOF-hybrid electrolytes promising for high-power and safer lithium-ion batteries.