부산대학교 도서관

In low-temperature CO2electrolysis, a fundamental trade-off exists between maximizing electrolyzer performance and minimizing downstream CO2recovery. By coupling a down-the-gas-channel electrolyzer model with a techno-economic analysis, we find that the optimal single-pass CO2conversion for ethylene production is typically low—on the order of 5%–10%—although larger optima are found if the H2faradic efficiency is very low. Similarly, strategies for eliminating carbonate crossover require more energy than downstream gas separation if they increase the cell potential by ∼0.2 V; however, when CAPEX are accounted for, this “break-even” voltage increases to ∼ 0.4 to 0.8 V for electricity prices varying from 6c/kWh to 1.5c/kWh. These findings are a consequence of the low energy requirements of industrial gas separation relative to electrochemical CO2reduction. Under most circumstances, maintaining near-optimal electrolyzer performance is more important than reducing or eliminating downstream gas separations.