Directly-Deposited Ultrathin Solid Polymer Electrolyte for Enhanced CO_2 Electrolysis

摘要

The economic viability of carbon dioxide electroreduction (CO_2R) relies onimproved performance accompanied by scalable system design. Membranesare commonly used for the separation of reduction and oxidation products aswell as to provide a suitable micro-environment for CO_2R. Commercial membranesoften address only one of the key challenges in CO_2R: either they offera suitable micro-environment for CO_2R (e.g., anion exchange membrane)or suppress carbonate cross-over (e.g., cation exchange membrane andbipolar membrane). This work presents a cation-infused ultrathin (≈3 μm)solid polymer electrolyte (CISPE) that concomitantly addresses both challengesvia a bidirectional ion transport mechanism and suppressed cathodeflooding. This directly-deposited CISPE (that substitutes the commonly usedpre-made membrane) enables record high full-cell energy efficiency of 28 at100 mA cm~(?2) for one-step CO_2 electrolysis to ethylene (C_2H_4) with ≈110 h ofstable operation. This translates into a record low energy cost of 290 GJ perton C2H4 for the end-to-end process (i.e., CO_2 capture and electroreduction,carbonate regeneration, CO_2 separation from anode and cathode streams)in a membrane electrode assembly CO_2R. The present work offers a versatiledesign paradigm for functional polymer electrolytes, opening the door tostable, and efficient electrolysis of high-value feedstock chemicals and fuelsusing low-cost catalysts.