(733e) Non-Equilibrium Continuum Modeling of Energy Recovery in Forward-Biased Bipolar Membranes
AIChE Annual Meeting
2024
2024 AIChE Annual Meeting
Transport and Energy Processes
Transport and Energy Processes at Electrochemical Interfaces III
Thursday, October 31, 2024 - 4:25pm to 4:40pm
In this work, an experimentally-validated continuum modeling framework is developed to elucidate mechanisms of transport and recombination in FB-BPMs. Simulations reveal that open-circuit voltage (OCV) in FB-BPMs is a dynamic property controlled by the intricate balance of ion-recombination and crossover, and that the presence of competitive counter-ion impurities significantly attenuates limiting current density of FB-BPMs through selective competition with H+ and OHâ for sites within the ion-conducting polymer layers. Additionally, fixed-charge neutralization reduces the concentration of available sites that mediate the transport of H+ and OHâ, further diminishing limiting current densities. Collectively, the established theory underscores the importance of non-equilibrium transport and kinetic phenomena in dictating the efficiency and performance of FB-BPMs for energy recovery. The implications of the simulations are discussed in the context of CO2 electrolysis systems and energy storage systems that employ FB-BPMs, and guidelines for the development of future FB-BPM materials and devices are presented.