New Design Cuts Cost Of Removing Greenhouse Gas From Industrial Emissions

A Johns Hopkins team has traded conventional components for a next gen battery powder that could reduce the cost of removing carbon dioxide from industrial emissions and the air.

Johns Hopkins researchers have created a new carbon-capture system that eliminates costly materials used in current electrochemical designs, potentially making it cheaper to remove carbon dioxide from industrial emissions and the air.

The research, using a component from new types of batteries, was published in September 2026 in Nature Chemical Engineering. The findings will also be presented during the 2026 AIChE Annual Meeting in November.

To meet net zero emissions of greenhouse gases by 2050, scientists have been studying new methods to remove airborne and industrial emissions of carbon dioxide (CO₂).

One such method—electrochemically mediated carbon capture, or EMCC—has emerged as a potential alternative to conventional carbon capture because it uses electricity rather than heat or pressure to capture and release CO₂. Conventional carbon capture, such as chemical scrubbing, is energy-intensive and rely on large infrastructures.

“Carbon capture is expected to play an important role in efforts to mitigate climate change. But conventional systems often require large amounts of heat to separate carbon dioxide from other gases,” says Yayuan Liu, the Russell Croft Faculty Scholar and assistant professor in the Department of Chemical and Biomolecular Engineering. “Electrochemical systems could offer an alternative, but many depend on membranes that can be expensive, wear out, and allow chemicals to leak between different parts of the equipment.”

Conventional membranes are usually made with polymers to separate the CO₂ capturing chemicals from the other side of the electrochemical cell. The new system eliminates the membrane by using a solid material called sodium iron phosphate, a powder also used as an electrode material in batteries. The scientists pair it with a chemical called 4,4’-azopyridine, or AzPy, that works with sodium iron phosphate to capture CO₂ when an electric current is applied and releases the greenhouse gas when the process is reversed.

“This ‘membraneless’ approach to carbon capture replaces the ion-exchange membrane normally used to separate parts of the reactor with a solid-state electrode,” says Andong Liu, doctoral student and principal author. “This means that the system can avoid problems associated with membrane degradation, chemical crossover and the added resistance of a membrane.”

The team tested several solid materials before selecting sodium iron phosphate for the system. They found that the sodium ion’s movement in material played an important role in how quickly the system could operate and how much CO₂ it could capture. The findings could help future developments of more efficient materials for not only carbon capture systems but also related fields such as energy storge and resource recovery.

Using sodium iron phosphate, the system operated for 75 capture-and-release cycles over 350 hours with a gas mixture containing 10% CO₂, capturing an average of 89.8% of its potential CO₂ capacity. In earlier tests, the researchers found that the membraneless system captured a greater share of its potential CO₂ capacity than a conventional membrane-based system, while also avoiding the higher resistance and performance losses associated with the membrane.

When tested under conditions designed to resemble real-world applications, the system captured and released CO₂ more quickly than conventional carbon capture systems without a major loss in performance.

At 400 parts per million CO₂, about the concentration found in ambient air, the system operated for 80 cycles over 210 hours and captured an average of 58.6 percent of its potential capacity.

The system also worked when oxygen, a common impurity in practical capture scenarios, coexists with CO₂. Using simulated air containing 400 parts per million CO₂ and 20% oxygen, the system operated for 40 cycles over 92 hours.

“We found that this system can capture CO₂ and release it into a nearly pure CO₂ stream. This is extremely important for capturing carbon from industrial emissions or air that needs to be concentrated before it is transported, stored, or used,” says Andong Liu. “We are hopeful that these findings will not only make it easier and less costly to capture CO₂.”

An economic analysis conducted by the team estimates that a conventional membrane-based system costs about $207 per ton of CO₂ captured. The membrane itself accounted for 28.9 percent of that cost.

“By eliminating the membrane and using methods to regenerate sodium iron phosphate, we estimate the cost could fall to about $148 per ton,” says Andong Liu. “With further improvements to equipment, materials, and electricity supply, the costs could eventually fall to $58.20 per ton for capturing CO₂ from concentrated sources.”

For ambient air capture, the researchers estimated that the conventional membrane-based system would cost about $1,233 per ton of CO₂. Improvements to capture efficiency and equipment could reduce the estimated cost to about $284 per ton.

The new membrane-free design can also be scaled to increase production by stacking multiple electrochemical units, allowing the system to be adapted for different sources of carbon dioxide.

“This work establishes a robust, scalable, and economically viable platform for advancing next-generation electrochemical carbon capture technologies,” says Yayuan Liu. “We hope that future improvements to our materials and equipment will allow us to operate at a larger scale to meet industrial demands.”

Collaborators on this project include the Department of Chemical and Biomolecular Engineering’s Anmol Mathur, Krish N. Jayarapu, Zhengyuan Li, Tianchen Li, and Gabryelle McDaniel.

This research was supported by Johns Hopkins University, the National Science Foundation, and the David and Lucile Packard Foundation.