Using direct sunlight to power the electrochemical reduction of waste CO2 to generate value added products could form the basis of a sustainable carbon cycle to make solar fuels. The polymer electrolyte membrane is one of the most critical components of a CO2 electrolyzer as it selectively transports reactants and prevents unwanted gas crossover. Lack of highly conductive ionomers and polymer electrolyte membranes with superior mechanical robustness and permeation limit the application of solar fuels technology. This projectâs goal is to develop a new type of visible light transparent polymer with an aromatic backbone structure with high performance and good durability for CO2 electroreduction. Based on the current outstanding linear polymer materials fabricated for CO2 conversion, a series of branched polymer electrolyte membranes will be developed with the material properties tailored for solar fuel generator. The main technical objectives are to suppress the swelling behavior, gas crossover, CO2 plasticization and improve the mechanical durability. The new ionomers and membranes will then be tested in a CO2 electrolyzer. Results of characterization and performance tests will provide feedback and guide development in large-scale production. The novel integration of aromatic backbone polymer and branching unit will provide a viable solution to fabricate a large area polymer electrolyte membrane and ensure durable performance in solar fuel production. Utilizing low-cost and abundant solar energy to convert CO2 to fuel and value-added chemicals could positively impact the global carbon balance, reduce air pollution, and create new jobs in regions with few opportunities by distributing the production of these materials
