Conventional aqueous supercapacitors face limitations in extreme temperatures due to water evaporation. To address this, a team from Shandong University designed a hybrid electrolyte by blending potassium trifluoromethanesulfonate (KOTf) with the ionic liquid EMIMNTf₂. This combination reshapes the solvation structure around potassium ions, reducing free water activity and suppressing harmful side reactions.
Through solubility tests and molecular dynamics simulations, the team identified EMIMNTf₂ as the optimal additive. The resulting electrolyte exhibits a 3.37 V electrochemical stability window and operates reliably from 0 to 100°C. At 60°C, supercapacitors retained 81.8% capacity after 10,000 cycles, outperforming existing WIS-based devices. This work bridges the gap between high voltage and thermal stability, also enhances safety, critical for real-world deployment. The study, published in Science Bulletin , highlights the potential of ionic liquids to revolutionize next-generation energy storage systems.
Science Bulletin
Experimental study