The Unusual Conductivity of Na in PEO-Based Statistical Copolymer Solid Electrolytes: When Less Means More.

The low conductivity of Na electrolytes in solid polymer electrolytes (SPEs) curtails the development of Na polymer batteries. In this study, NaClO (3-24 wt %, 90-9:1 O:Na) is dissolved in statistical copolymers of ethylene oxide (EO) and propylene oxide (PO) (0-20 mol %). Remarkably, the conductivity of these SPEs increases as the concentration of Na decreases, thus departing from the usual Nernstian behavior.