All solid-state lithium-ion batteries based on designed polyrotaxane-containing networks

Abstract

Selecting the appropriate polymer structure for use as both a solid electrolyte and catholyte is essential for enhancing the electrochemical performance of all-solid-state lithium metal batteries. In this study, we are pioneering the customization of solid electrolyte and catholyte synthesis based on novel polyrotaxane (PRX)-containing polymer networks by altering the length of the polyether crosslinkers to tune the properties to meet specific needs of different components. On one hand, the modified PRX polymer networks based on the shorter crosslinker show good mechanical strength, high ionic conductivity (7.25 × 10−4 S cm−1) and high lithium ions transference number (0.54) at 60 °C, allowing their use as solid polymer electrolyte (SPE) self-supporting membranes. On the other hand, all-solid-state lithium-ion batteries with this SPE demonstrate a much higher initial capacity (above 160 mAh/g using LiFePO4 as active material at the cathode and lithium metal as anode), and better cycling performance when paired with longer cross-linked PRX as catholytes than the other non-customized combinations all solid lithium-ion batteries. Moreover, the cycling performance of the full cell can be further improved by incorporating different lithium salts in the electrolyte (LiTFSI) and cathode (LiClO4). This work highlights that the customized design of solid electrolytes and catholytes based on polymer networks is an efficient strategy to obtain high-performance all-solid-state lithium metal batteries