Abstract: A method for separating a Lewis acid gas from a fluid mixture, comprising contacting the fluid mixture with a reduced electroactive species; a non-aqueous electrolyte; and a stabilizing additive to form an anion adduct between the Lewis acid gas and the reduced electroactive species, wherein the electroactive species comprises an oxidized state, and at least one reduced state that bonds with the Lewis acid gas to form the anion adduct, wherein the stabilizing additive comprises a cationic Lewis acid, a hydrogen-bond donor, or a combination thereof, and the stabilizing additive is present in an effective amount to kinetically favor the forming of the anion adduct from the reduced electroactive species and thermodynamically favor the forming of the anion adduct in the thermodynamic equilibrium between the anion adduct and the reduced electroactive species.

Abstract: A quinone-containing poly(arylene) includes repeating units of formula (I), (II), (III), (IV), (V), or (VI) as defined herein. The quinone-containing poly(arylene) can be useful in composites, electrode assemblies, electrochemical cells, gas separation systems, energy storage devices, and electrochromic devices.