Water Domain Enabled Transport in Polymer Electrolytes for Lithium-Ion Batteries

Widespread commercial adoption of polymer electrolytes for lithium-ion batteries has been hindered by subpar transport properties, namely, ionic conductivities of <1 mS/cm at room temperature and slower Li + compared to anion transport. The developed polymer and water-in-salt electrolyte demonstrated preferential Li + transport compared to the anion via pulsed field gradient NMR, acceptable ionic conductivities of >1 mS/cm at 25 °C, and an extended electrochemical stability window compared to water-in-salt electrolytes. This polymer electrolyte has a flexible liquid/solid transition through polymer molecular weight tuning, and both liquid and solid iterations are investigated. MD simulations provided additional insight into the Li + solvation environment and the mechanism of fast, preferential Li + transport through percolation of water-rich Li + (H 2 O) n nanodomains inside the poly(ethylene oxide) matrix.