Nanostructured Metal-Organic Framework (MOF)-Derived Solid Electrolytes Realizing Fast Lithium Ion Transportation...

Solid-state batteries are hindered from practical applications, largely due to the retardant ionic transportation kinetics in solid electrolytes (SEs) and across electrode/electrolyte interfaces. Taking advantage of nanostructured UIO/Li-IL SEs, fast lithium ion transportation is achieved in the bulk and across the electrode/electrolyte interfaces; in UIO/Li-IL SEs, Li-containing ionic liquid (Li-IL) is absorbed in Uio-66 metal-organic frameworks (MOFs). The ionic conductivity of the UIO/Li-IL (15/16) SE reaches 3.2 × 10^-4 S cm^-1 at 25 °C. Owing to the high surface tension of nanostructured UIO/Li-IL SEs, the contact between electrodes and the SE is excellent; consequently, the interfacial resistances of Li/SE and LiFePO₄ /SE at 60 °C are about 44 and 206 Ω cm² , respectively. Moreover, a stable solid conductive layer is formed at the Li/SE interface, making the Li plating/stripping stable. Solid-state batteries from the UIO/Li-IL SEs show high discharge capacities and excellent retentions (≈130 mA h g^-1 with a retention of 100% after 100 cycles at 0.2 C; 119 mA h g^-1 with a retention of 94% after 380 cycles at 1 C). This new type of nanostructured UIO/Li-IL SEs is very promising for solid-state batteries, and will open up an avenue toward safe and long lifespan energy storage systems.