The present invention introduces ionic polymers featuring with a spiro structure, which enhances the solubility and gas permeability of the ionic polymer while maintaining excellent conductivity, mechanical properties, and dimensional stability. This is achieved by incorporating a spiro fragment with a large free volume into the polymer backbone. As a result, the gas permeability of the catalyst layer prepared from this ionic polymer is improved, making it suitable as a catalyst binder for proton exchange membrane fuel cells (PEMFCs) or anion exchange membrane fuel cells (AEMFCs). Furthermore, the electrochemical performance of the fuel cell is enhanced. Additionally, the proton exchange membrane and anion exchange membrane derived from this ionic polymer containing a spiro structure effectively improve the conductivity of both types of membranes by increasing the space volume due to the presence of the large free volume spiro fragment.

Provided herein are membrane electrode assemblies (MEAs) for CO.sub.x reduction. According to various embodiments, the MEAs are configured to address challenges particular to CO.sub.x including managing water in the MEA. Bipolar and anion-exchange membrane (AEM)-only MEAs are described along with components thereof and related methods of fabrication.