Enhancing the electrochemical properties of polyethylene oxide solid-state electrolytes based on a small nano-sized UiO-66 metal-organic framework

Metal-organic frameworks (MOFs) have garnered significant attention in the field of Lithium-ion batteries due to their porous periodic network properties. However, this is a challenge to design high-performance solid-state electrolytes reasonably. Herein, a small nano-sized MOF Small-UiO-66 is reported, which has high surface area and mesoporous properties that can effectively inhibit PEO matrix crystallization. The presence of Small-UiO-66 accelerates the dissociation of lithium salts, which disrupts the ordered arrangement of the PEO chain segments. The abundant Lewis acidic sites on the surface of Small-UiO-66 facilitate the construction of abundant Li+ transport channels and promote Li+ conduction. Furthermore, the smaller nano-sized increase the interfacial wettability with lithium metal, which promotes the uniform diffusion of Li+ and inhibits the growth of lithium dendrites. The results indicate that 0.1 Zr-CSE exhibits high ionic conductivities of 6.94 × 10−4 S/cm at 60 °C. Based on 0.1 Zr-CSE, the Li||Li symmetric cell can operate stably for 1200 h at a current density of 0.1 mA/cm2, and the LFP||Li cell also achieves a high initial capacity of 147.65 mAh·g−1 at current densities of 0.5C. This work presents a novel approach for preparing high-performance solid-state Lithium-ion batteries using MOFs as fillers for polymer solid-state electrolytes. [Display omitted] •MOF small-UiO-66 with small nano-sized blended into PEO matrix is prepared and employed as a composite solid-state electrolyte.•The Small-UiO-66 nanofiller can effectively inhibits PEO matrix crystallization, leading to a high ionic conductivity of 6.94 × 10−4 S/cm at 60 °C.•Small-UiO-66 contains rich pore structures on its surface that make it easier for Li+ diffuse uniformly, preventing lithium dendrite formation.•Small-UiO-66 favors the uniform Li+ diffusion and prevents the formation of lithium dendrites due to the small nano-sized.•The LFP.||Li solid-state lithium-ion battery incorporating the 0.1 Zr-CSE achieves exceptional cycling and rate performance.