Atomic-Scale Resolution of Ion Transport Behavior in a Flexible Polymer Electrolyte under Tensile/Compressive Strain and Electric Fields

Abstract Polymer electrolytes, due to their excellent flexibility and efficient ion-transport properties, are considered as the promising electrolyte materials for flexible power devices. However, the ion-transport mechanisms under mechanical strain and electric field remain insufficiently understood. In this work, molecular dynamics simulation is employed to construct models of un-cross-linked polyacrylamide-based polymer electrolytes containing 6 M potassium hydroxide and investigate the ion transport behavior under tensile/compressive strain and electric fields. The ionic conductivity of 93.90 mS·cm–1 decreases to 80.12 mS·cm–1 due to a tensile strain of 100% and it increases to 104.05 mS·cm–1 as a result of applied compressive strain, which show a tension inhibition and compression promotion trend. Under applied electric fields, the compressive strain plays crucial roles on the sensitivity of ion transport to the electric field across different strain modes. The work provides the atomic-level insight for designing high-performance polymer electrolytes in a practical electric-stress-coupled environment.