Synthesis and Comparative Studies of Solvent-Free Brush Polymer Electrolytes for Lithium Batteries

Abstract

For next generation lithium batteries, solid polymer electrolytes (SPEs) are essential to meet the challenges of higher safety standards, higher specific energy, and easy processing. Linear polyethylene glycol (PEG) based SPEs are by far the most investigated systems for these requirements. However, the weak mechanical properties, high crystallinity, and consequently moderate ionic conductivity prevent these systems from being used in electrochemical storage devices. We address the question of the influence of the polymer architecture on the above properties by synthesizing bottlebrush copolymers carrying PEG side chains and comparing their electrochemical properties and ionic conductivity with those of the respective linear PEG polymers. For obtaining bottlebrush polymers, first methacrylate (PEGMEMA) and norbornene (Nb-PEGME) macromonomers carrying PEG side chains were synthesized and polymerized using either free radical polymerization or ring-opening metathesis polymerization (ROMP), respectively. We ...