Directly-Deposited Ultrathin Solid Polymer Electrolyte for Enhanced CO2 Electrolysis

The economic viability of carbon dioxide electroreduction (CO2R) relies on improved performance accompanied by scalable system design. Membranes are commonly used for the separation of reduction and oxidation products as well as to provide a suitable micro-environment for CO2R. Commercial membranes often address only one of the key challenges in CO2R: either they offer a suitable micro-environment for CO2R (e.g., anion exchange membrane) or suppress carbonate cross-over (e.g., cation exchange membrane and bipolar membrane). This work presents a cation-infused ultrathin (approximate to 3 mu m) solid polymer electrolyte (CISPE) that concomitantly addresses both challenges via a bidirectional ion transport mechanism and suppressed cathode flooding. This directly-deposited CISPE (that substitutes the commonly used pre-made membrane) enables record high full-cell energy efficiency of 28% at 100 mA cm(-2) for one-step CO2 electrolysis to ethylene (C2H4) with approximate to 110 h of stable operation. This translates into a record low energy cost of 290 GJ per ton C2H4 for the end-to-end process (i.e., CO2 capture and electroreduction, carbonate regeneration, CO2 separation from anode and cathode streams) in a membrane electrode assembly CO2R. The present work offers a versatile design paradigm for functional polymer electrolytes, opening the door to stable, and efficient electrolysis of high-value feedstock chemicals and fuels using low-cost catalysts.

Automated summary

This research introduces a cation-infused ultrathin solid polymer electrolyte (CISPE) that addresses both challenges of CO2 electroreduction, using a bidirectional ion transport mechanism and suppressed cathode flooding. The deposition of CISPE enables a record high full-cell energy efficiency of 28% for one-step CO2 electrolysis to ethylene, with stable operation for approximately 110 hours. This work provides a versatile design paradigm for functional polymer electrolytes, enabling stable and efficient electrolysis of high-value feedstock chemicals and fuels using low-cost catalysts.