Synthesis and Characterization of a Phthalimide‐Containing Redox‐Active Polymer for High‐Voltage Polymer‐Based Redox‐Flow Batteries

Abstract A phthalimide‐containing redox‐active polymer is designed and synthesized in particular for the application in all‐organic redox‐flow batteries. 4‐Vinylbenzyl phthalimide is prepared in a one‐step reaction and copolymerized with a solubility promoting comonomer. The novel polymer is electrochemically characterized in various electrolytes via cyclic voltammetry and features a quasireversible reduction reaction at E 0 ½ = −1.89 V versus AgNO 3 /Ag. Afterward, the polymer is applied as anode‐active material in a first preliminary battery test in combination with a 2,2,6,6‐tetramethylpiperdinyl‐ N ‐oxyl‐containing polymer as cathode‐active material and a porous membrane as separator, yielding a polymer‐based all‐organic battery system with a high cell voltage of 2.0 V.