Multicomponent Materials as Li⁺ Conductors

Abstract

The conductivity and mechanical stiffness of ethylene-oxide based Li+ conducting solid polymer electrolytes (SPE) were measured and compared for a variety of single- and two-phase systems. Our objective was to determine whether there are simple correlations between these two properties despite the fact that these systems are truly complex. Results show that molecular architecture dominates both transport and mechanical behavior of single phase systems, thereby eliminating broad correlations. Conductivity was additionally found to require not only facile local chain dynamics but also a sufficient concentration of vacancies, as per the site hopping model. Two phase systems also show complex behaviors, but offer a broader range of both conductivity and stiffness values, and good conductivity/stiffness correlations.