RepAir and University of Delaware Show Battery-Based DAC Path Below $100 Per Tonne

RepAir Carbon and researchers from the University of Delaware have published peer-reviewed results showing that a rechargeable battery chemistry can pull CO2 straight from the air. The study appeared in Nature Energy on September 22, 2026.

The team built a symmetric nickel hydroxide battery cell paired with a hydroxide exchange membrane. The paper also lays out a pathway to direct air capture (DAC) costs below US$100 per tonne of CO2.

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Why Electrochemical DAC Matters

Conventional DAC relies on thermal swing sorption, which the authors describe as energy intensive. Electrochemical capture takes a different route.

It runs on electricity, so it can use renewable power and skip the heating step altogether. The catch? According to the paper, few electrochemical designs have combined low energy use, long durability and full CO2 purification.

Scale-up and pressure drop are also rarely tested for these devices. This study takes on both.

What the Tests Showed

Long-Duration Lab Testing

A laboratory-sized 25 cm² device ran for 5,000 hours, which is more than half a year of operation. That's notable in a field where the authors say demonstrations are often limited to small devices and short lifetimes.

Scaling Up to a Pilot Stack

The team then scaled up to a stack of nine 300 cm² cells. Over a 48-hour test, the stack reached an energy cost of 0.83 MWh per tonne of CO2 and a flux equal to about 75 kg of CO2 per square metre each year.

The pilot-scale stack also met the 300 Pa pressure drop requirement for DAC. That's an important box to tick for any system that has to move large volumes of air.

A Clear Cost Roadmap

Using learning rates from energy technologies, the paper presents a pathway to below US$100 per tonne. The authors say this shows electrochemical DAC's potential as a climate solution.

A Strong North American Research Link

The University of Delaware researchers received support from the US Department of Energy's National Energy Technology Laboratory and the US Army Research Laboratory. The project was supervised by Yushan Yan and Brian Setzler, and Yan is also a co-founder of RepAir.

Newark, Delaware-based Versogen supplied the PiperION membranes and ionomer used in the work. RepAir's team led the scale-up effort, including durable electrodes, stack hardware and the system that runs the DAC process.

From Lab to Production Line

RepAir's commercial platform, the ElectraStack, stacks hundreds of individual cells into interlocking modular units. The company says its fully electric, solid-state process needs no heat, liquids or solvents and produces 98 to 99% pure CO2.

RepAir uses mass-produced nickel electrodes and replaces traditional metal parts with injection-molded, recycled polymers. It also plans to build gigafactories with manufacturing partners to scale production quickly.

About RepAir Carbon

RepAir Carbon develops electrochemical carbon capture technology for both direct air capture and low-concentration point sources, such as aluminum smelters and gas turbines. The company says its system uses 70% less energy than other solutions on the market.

RepAir raised $15 million in April 2025 and secured €12.5 million from the European Innovation Council in July 2025. In March 2026, it opened a European office in Luxembourg.