Ionic Phase-segregated Liquid Crystal/Polymer Electrolyte for Lithium-ion Transport*

Solid polymer electrolytes have been widely studied for applications in lithium-ion batteries due to the potential for improved thermal and electrochemical stability.[1] Poly(ethylene oxide) (PEO) based electrolytes are the most widely studied solid polymer electrolyte. The conductivity of liquid-free PEO-based electrolytes is limited by ethylene oxide chain segmental motion.[2] In the present work, we seek to investigate lithium-ion transport via a different mechanism, lithium-ion transport through ionic domains. Ionic liquid crystal (LC) model small molecules and related single-ion conducting side-chain polymer electrolytes were synthesized. Small-angle X-ray scattering shows that both the LCs and polymers present segregated ionic phases. Impedance spectroscopy measurements indicate that both materials present Vogel-Tammann-Fulcher temperature-dependent conductivity. Current efforts are focused on macroscopic alignment of ionic phase for mitigation of grain boundary effects and studying the effect of anion structure on lithium-ion transport.

[1] L. Long, S. Wang, M. Xiao, and Y. Meng, Journal of Materials Chemistry A 4, 10038 (2016).
[2] W. H. Meyer, Advanced Materials 10, 439 (1992).