US Patent 9849450 Ion-conducting membranes

An anion-conducting polymeric membrane comprises a terpolymer of styrene, vinylbenzyl-Rs and vinylbenzyl-Rx. Rs is a positively charged cyclic amine group. Rx is at least one constituent selected from the group consisting Cl, OH and a reaction product between an OH or Cl and a species other than a simple amine or a cyclic amine. The total weight of the vinylbenzyl-Rx groups is greater than 0.3% of the total weight of the membrane. In a preferred embodiment, the membrane is a Helper Membrane that increases the faradaic efficiency of an electrochemical cell into which the membrane is incorporated, and also allows product formation at lower voltages than in cells without the Helper Membrane.