“Acid-in-chain” versus “base-in-chain” anionic polymer electrolytes for electrochemical devices

Abstract

We extend an earlier study of high conducting polyanionic (single ion conducting) electrolytes, obtained by Lewis acid plasticization of polyanions in which the in-chain anions are Lewis base in character, to the inverse case in which the Lewis acid is incorporated in the chain. The Lewis acid groups in the chain are spaced by polyethylene oxide segments of variable length. Such “Acid-in-chain” polymers are then turned into polyanions by reaction with a Lewis base anion, leaving the counter cation free to conduct. Depending on the Lewis base strength of the added anion, this type of system can range from strictly polyanionic to weakly anion trapping in nature. Conductivities in the range of 10 −5–10 −4 S/cm have been obtained. In the case of short interanionic spacers, high conductivities at T g have been observed, implying that the conducting modes are decoupled from the segmental modes and that the conductivity is therefore superionic glass-like in nature and presumably unicationic. Such polymers may serve alone as solid-state electrolytes, or as the polymer component for polymer-in-salt ionic rubber electrolytes.