Incorporating Record-Breaking Catalysts in Electrospun Bipolar Membranes for Low-Cost Carbon Capture via Salt Splitting

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OPEN 2021
Golden, Colorado
Project Term:
09/30/2022 - 09/30/2025

Critical Need:

Direct air capture (DAC) and direct ocean capture (DOC) are the two predominant paradigms to capture carbon dioxide (CO2) from ambient environments—but current approaches are too capital intensive and energy inefficient to meet long-term carbon capture cost targets. One DAC approach involves a system where ambient air flows over a chemical solvent that selectively removes the CO2 while in DOC seawater itself is the capture solvent. Intentionally manipulating the pH can release the CO2 as a concentrated stream for disposal or reuse while regenerating the solvent in a typically highly energy-intensive process. New approaches are needed for solvent regeneration with much lower energy consumption to dramatically lower the operating cost of carbon capture.

Project Innovation + Advantages:

Coupled acid and base formation is a key part of the DAC and DOC cycle regeneration step. The National Renewable Energy Laboratory (NREL) will dramatically reduce acid/base production costs by developing advanced electrodialysis systems to split salt to enable electrochemical sorbent regeneration in contrast to the high-temperature, natural-gas-fired calcination step used today. NREL and its partners aim to improve the performance, durability, and manufacturability of bipolar membranes (BPMs)—critical components of electrodialysis devices—using three-dimensional interfaces and new catalysts that speed up the dissociation of water molecules into acid and base. The BPMs will be produced on roll-to-roll manufacturing equipment at near commercial scale. The electrodialysis devices will operate at ten times the rate and greater energy efficiency than current technology. Driving electrodialysis with carbon-free electricity for DAC/DOC enables scalable environmental CO2 capture and could significantly reduce DAC/DOC operating costs.

Potential Impact:

If successful, this project will produce mass-manufacturable bipolar membranes incorporating highly efficient catalysts and advanced 3D interfaces with unrivaled performance and durability for DAC and DOC.


The production of BPMs and electrodialysis stacks by U.S.-based companies will ensure the U.S. maintains a technological lead in developing and deploying advanced carbon capture technologies.


After project completion, BPM production will be scaled to produce ~680 stacks per year. Their combined CO2 mitigation capacity would exceed 12 Mt/y; production for 8 years would mitigate >1 Gt/y of CO2.


The new system’s improved design, process improvement, economies of scale, and labor efficiency are projected to result in a 30% cost reduction over 10 years. Large savings are expected from using low-cost renewable electricity generation.


ARPA-E Program Director:
Dr. Philseok Kim
Project Contact:
Todd Deutsch
Press and General Inquiries Email:
Project Contact Email:


Carbon Engineering
Electrosynthesis Company, Inc.
eSpin Technologies
University of Oregon

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