Scalable CO₂ Removal Using Electricity: Research Needs in Bipolar Membrane Electrodialysis

Electrochemical direct air capture (DAC) potentially represents a transformative solution in the fight against climate change. Herein we provide a critical perspective on pH-swing approaches, which leverage pH shifts to enhance CO₂ capture and release while minimizing energy demands and improving scalability. In particular, bipolar membrane electrodialysis offers promise. Widespread adoption requires overcoming challenges across molecular, micro-, and system scales. At the molecular scale, development of durable ion exchange layers and their integration into bipolar membranes with high ion conductivity, permselectivity, and stability is critical. At the microscale, stack designs must minimize energy losses by optimizing fluid dynamics, current densities, faradaic efficiencies, and pH gradients. At the system level, scalable DAC systems must integrate renewable energy and advanced CO₂ uptake strategies, such as enhanced solvent/electrolyte formulations and innovative reactor configurations. By addressing these milestones, electrochemical DAC can achieve intensified processes with improved energy efficiency, reduced costs, and higher CO₂-removal capacities.