Advancements in Polymer Blend Electrolytes for Lithium-Ion Conduction

Abstract

Increasing the energy density of lithium-ion batteries requires, among other advances, electrolytes that are compatible with lithium metal and next-generation cathodes. Polymer electrolytes play an important role in this regard, but overcoming slow ion transport is a major challenge. Hybrid electrolytes that combine fast ion transport of ceramic electrolytes and processability of polymer electrolytes are promising. To take advantage of transport in both phases, transference numbers should be comparable. Thus, single-ion conducting polymer electrolytes have received major focus in recent years. In addition to the benefit in hybrid electrolytes, single-ion conduction yields numerous transport and efficiency advantages in neat polymer electrolytes. Due to formulation simplicity and motivated by block copolymer advancements, our team has focused on polymer blend electrolytes. State of the art in these electrolytes will be reviewed including recent advancements from our team using precision polyanions with polyether solvating polymer. This presentation will cover miscibility, conductivity, and transference numbers as a function of composition and temperature. Distinct differences between blends containing the different anionic forms will be explained in the context of ion correlation. Important future directions for the subfield of polymer blend electrolytes will also be discussed.