Multifunctional phosphonium-based ionic liquid embedded polymer electrolyte for dual energy conversion and storage

In the realm of green and sustainable energy use, solid electrolytes are recognized for their environmentally friendly and degradable properties. Simultaneously, significant efforts have been made to improve the ionic transport and interfacial stability of polymer electrolytes to facilitate the development of electrochemical devices. In this context, the influence of the phosphonium-based ionic liquid (PBILS), Tributylmethylphosphonium bis(trifluoromethane sulfonyl)imide, on the polyethylene oxide polymer electrolyte and its use in electrochemical applications is investigated. The optimized polymer electrolyte formulation, combined with 20 wt % ionic liquids, exhibits an ionic conductivity of approximately 7.17 × 10−4 S/cm at room temperature, along with a wide electrochemical stability window and remarkable thermal stability. The unique aspect of this work is the dual applicability of the PBIL-based polymer electrolyte, which was successfully used as a common electrolyte in both dye-sensitized solar cells (DSSCs) and electric double-layer capacitors (EDLCs). This dual functionality of the PBIL-based polymer electrolyte demonstrates its versatility, making it an exceptional candidate for energy storage and conversion systems.