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Unraveling Ion Transport in Trifluoromethanesulfonimide Pentablock Copolymer Membranes in Nonaqueous Electrolytes...

by Michelle Lehmann, Guang Yang, Jagjit Nanda, Tomonori Saito
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7740 to 7751

Cation exchange membranes provide a key function in various nonaqueous energy storage technologies. As such, understanding the role of a nonaqueous liquid electrolyte on ion transport through a membrane is imperative. This study unravels relationships between membrane ion transport and electrolyte salt concentration utilizing a trifluoromethanesulfonimide-based pentablock copolymer membrane with polar and nonpolar nonaqueous electrolyte solutions. The membrane plasticized with propylene carbonate (PC) exhibits a single-ion conductivity of 9.3 × 10–6 S/cm at 25 °C. Tailoring the nonaqueous electrolyte and electrolyte salt concentration enables the single-ion conducting membrane to maintain a high cation transport number, >0.75, and boost ion conductivity more than 10 times to 1.3 × 10–4 S/cm at 25 °C for the PC-based electrolyte solution. The findings provide critically important design parameters for energy storage systems utilizing nonaqueous electrolytes, such as Li- and Na-ion batteries and nonaqueous flow battery technologies.