In situ polymerization of dicationic pyrrolidinium-based solid polymer electrolytes for high-performing and long-lasting lithium-ion batteries

Abstract

Solid-state polymer electrolytes (SPEs) are considered promising electrolytes for next-generation lithium-ion batteries because of their superior safety, long life and high energy density. In this study, we have developed an advanced SPE via the in situ thermal polymerization of vinyl ethylene carbonate (VEC) with trimethylolpropane ethoxylate triacrylate (ETPTA) as a multifunctional crosslinker, incorporating a pyrrolidinium-based dicationic ionic liquid (DIL). The in situ crosslinking polymerization strategy resulted in a highly stable DIL-incorporated SPE (DIL@SPE) with a uniform polymer network and enhanced interfacial compatibility with the electrodes. The DIL@SPE exhibited an ultrahigh ionic conductivity of 3.85 × 10⁻³ S cm⁻¹ at 30 °C and a lithium-ion transference number (t_Li⁺) of 0.55. Consequently, Li|DIL@SPE|Li symmetric cells demonstrated stable lithium plating/stripping behaviour at 0.1 mA cm⁻² for 500 h. Moreover, the cell assembled with the configuration of LFP|DIL@SPE|Li delivered a high discharge capacity of 133 mA h g⁻¹ at 0.5C and retained 75% of its capacity after 500 cycles. This work offers a viable strategy towards the development of sustainable, high-performance, and stable SPEs for advanced LIB technologies.