PVDF-HFP/SiO2 composite solid electrolyte enhanced by supramolecular self-assembly of cyclodextrin

The utilisation of solid electrolytes in the manufacturing of high-energy density and very safe solid state lithium batteries exhibits significant promise. Due to its excellent machinability and flexibility, the composite solid electrolyte has drawn increasing attention. However, it was unable to develop further due to the organic phase's chemical incompatibility with the inorganic phase. In this paper, a type of composite solid electrolyte reinforced by supramolecular self-assembly material is therefore presented. PVDF-HFP serves as the polymer matrix, whereas βCD-MSN is the inorganic filler. In addition to creating a suitable organic-inorganic interface, the abundant hydroxyl groups in βCD-MSN can strongly interact with the -F group of PVDF-HFP to degrade the conductive chain segment and increase the lithium ion conductivity (2.71 × 10−5S/cm). At the same time, βCD-MSN also has the advantages of high specific surface area and active site, which can inhibit the movement of anions in the solid electrolyte to a certain extent, and obtain a high lithium ion migration number (0.65). Based on the above advantages, we assembled a solid state symmetric lithium battery containing βCD-MSN and a lithium iron phosphate battery, which showed good electrochemical performance and stability at room temperature. Different from previous studies, composite solid electrolytes designed by supramolecular self-assembly materials can balance the relationship between ionic conductivity and mechanical strength of solid electrolytes to a certain extent. This will provide new insights for subsequent researchers to design a new generation of composite solid electrolytes.