A novel pyridinium-based organic ionic plastic crystal for ambient temperature solid polymer electrolytes.

The development of solid polymer electrolyte (SPE) systems is a promising strategy for improving the safety of lithium batteries. However, the practical implementation of these systems is often hindered by their limited ionic conductivity at ambient temperatures and poor interfacial contact with the electrodes. To address these issues, a novel pyridine-based organic ionic plastic crystal (OIPC) was synthesized and combined with poly(vinylidene fluoride-co-hexafluoropropylene) (PVH) and lithium bis(fluorosulfonyl)imide (LiFSI) to create a porous SPE, which was named SPE-Pyr₁FSI/PVH (80:20). The SPE possessed desirable characteristics such as remarkable mechanical properties, nonflammability, high ionic conductivity (1.18 mS cm⁻¹ at 25 °C), and a large electrochemical window (5.85 V vs. Li⁺/Li). Moreover, solid-state Li/LiFePO₄ cells based on this SPE exhibited excellent rate capability, as well as cycling performance at ambient temperature. Specifically, the discharge capacity of the cells remained at 134.0 mAh g ⁻¹ at 1.0 C current density over 500 cycles. This study provides new insights into the design of ambient temperature solid-state electrolytes for lithium batteries and highlights the efficacy of OIPC in enhancing the performance of SPEs. [ABSTRACT FROM AUTHOR]