Investigation of molten carbonate electrolysis cells performance for H2 production and CO2 capture

Molten carbonate electrolysis cells have recently gained interest for the sustainable production of H-2 or syngas to substitute fossil fuels. However, they can be also used for CO2 sequestration, as they pump it from one electrode inlet to the opposite electrode outlet. Thus, they can easily be applied to segregation of CO2 from H-2 based fuels while also increasing the fuel heat of combustion for example after a steam reforming reactor. To explore the use of molten carbonate electrolysis cell for this application, in this work the authors investigate the performance of the cell under different operating conditions in term of both operating temperature and fuel electrode gas composition. Polarization curves, gas crossover and electrochemical impedance spectroscopy are used to evaluate specific issues (high electrolyte losses due to water and temperature) or benefits (excess of H2O in regard to CO2 that allows for higher CO2 capture rate). After, a series of long-term tests at-150 mA cm(-2) and 650 degrees C are performed to demonstrate long term stability. In particular, before electrolyte loss made the performance unstable, different cells are operated for about 1000 h with an average voltage of about 1.14 V demonstrating also the repeatability of such tests.

Automated summary

Molten carbonate electrolysis cells have the potential to sustainably produce H2 or syngas as alternatives to fossil fuels, as well as sequester CO2. The performance of the cell is influenced by various factors such as operating temperature and fuel electrode gas composition. Understanding these factors can help improve electrolyte loss and increase CO2 capture rate.