Effect of intermolecular interactions on the performance of UiO-66-laden solid composite polymer electrolytes

Solid composite polymer electrolytes have been proposed as high-performance solid electrolytes for next-generation energy storage devices. In particular, UiO-66 with monodispersed size (400 nm) and morphology and outstanding stability was introduced as a functional filler to modify the electrochemical properties of poly(ethylene oxide) (PEO) solid electrolytes with LiClO 4 as the lithium salt. The desired physicochemical properties and electrochemical properties of the electrolyte was improved through microstructure regulation and the intermolecular interactions, as confirmed by X-ray diffraction, differential scanning calorimetry , optical microscopy and electrochemical characterisation. Owing to the intermolecular interactions, crystallisation of PEO was inhibited, and the ionic conductivity of the solid composite polymer electrolyte increased to 4.8 × 10 −5  S cm −1  at 25 °C. Electrochemical stable window and lithium ion transference number (t + ) were also observably enhanced. The assembled LiFePO 4 /PEO-LiClO 4 -UiO-66/Li solid-state lithium batteries exhibited excellent cycling and C-rate performances. The initial discharge capacity reached to 160 mAh g −1 , and superior cycle stability with a capacity retention ratio of 83% after 200 cycles at 1C current and 80 °C was achieved. The discharge capacity at 5C was improved by 232%. This work provides new insights into boosting the performances of solid composite polymer electrolytes through intermolecular interactions.