Building Sodium Metal Battery with Polyisoprene-Based Air-Stable Single-Ion Gel Polymer Electrolyte

The intrinsically safe, flexible, single-ion gel polymer electrolytes with a high transference number (0.75) have been developed by making the proper blending of a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) copolymer and biocompatible poly((sulfamate-carboxylate) iso-prene) (PISC) when soaked in carbonate solvents. More interestingly, a steady conductivity of 1.81 x 10-5 S/cm is observed for 15 days under normal air exposure conditions (RH = 45%-61%, T = 25-31 degrees C). The sodium metal battery with an NVP cathode demonstrates charge/discharge cycling at 80 degrees C with 82% capacity retention at a C/5 rate after 45 cycles. To trigger cycling performance at room temperature, the gel is formed with a conventional liquid electrolyte and a capacity retention of 67.92% after 200 cycles (C/10 rate) even after air exposure to the electrolyte.

Automated summary

Flexible and intrinsically safe single-ion gel polymer electrolytes with high transference number (0.75) were developed by blending poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) copolymer and biocompatible poly((sulfamate-carboxylate) iso-prene) (PISC) in carbonate solvents. A steady conductivity of 1.81 x 10-5 S/cm was observed for 15 days under normal air exposure conditions (RH = 45%-61%, T = 25-31 degrees C). The sodium metal battery with an NVP cathode showed 82% capacity retention after 45 cycles at 80 degrees C with a C/5 rate, and 67.92% capacity retention after 200 cycles at room temperature with a C/10 rate using the gel formed with a conventional liquid electrolyte even after air exposure.