Polymer blend electrolytes with enhanced room temperature conductivity for lithium-ion batteries

• Olivia Kelly, Chemical Engineering, University of Delaware

• Thomas H., III Epps, Chemical Engineering, University of Delaware

Solid polymer electrolytes are safer alternatives to conventional liquid electrolytes currently used in lithium-ion batteries. The benchmark solid polymer electrolyte is polyethylene oxide (PEO) doped with lithium salt due to its high conductivity above the melting point of PEO. However, the room temperature ionic conductivity of this system has been largely limited by the semi-crystallinity of the PEO below ~60 ^oC. The disruption of PEO crystallinity is expected to raise the room temperature ionic conductivity by maximizing the amorphous (ion-conducting) regions, in which effective ion transport can occur due to sufficient polymer segmental relaxation. Herein, PEO was blended with other polymers to fabricate binary miscible blends at various compositions (in terms of the polymer molecular weight and ion concentration), with the goal of disrupting the crystal formation to realize faster and more efficient ion transport. The effect of the electrolyte composition on the thermal and conductive properties is being investigated to help optimize the system. The polymer blend electrolytes are expected to have enhanced room temperature conductivity with the ability to unlock applications for solid polymers in battery usage.