Engineers at MIT have designed a novel electrode that significantly enhances the efficiency of converting carbon dioxide into valuable products, offering a promising solution to reduce greenhouse gas emissions.
Researchers at the Massachusetts Institute of Technology (MIT) have developed an innovative electrode design that could significantly enhance the efficiency of converting carbon dioxide (CO2) into valuable products like ethylene. This breakthrough promises to advance efforts to reduce greenhouse gas emissions and turn CO2 into useful commodities, such as fuels, plastics and chemical feedstocks.
In a study published in Nature Communications, a team led by MIT graduate student Simon Rufer and mechanical engineering professor Kripa Varanasi unveiled a new approach to overcome a longstanding challenge in CO2 electrochemical conversion.
Using a combination of plastic material PTFE (essentially Teflon) and conductive copper wires, they created electrodes that balance electrical conductivity and hydrophobic properties.
“The CO2 problem is a big challenge for our times, and we are using all kinds of levers to solve and address this problem,” Varanasi said in a news release.
The need to find economical and scalable methods for converting CO2 into useful products is essential, both to make use of captured carbon and to cut reliance on petroleum-based production processes.
While current methods can convert CO2 into ethylene and other chemicals, they often lack the required efficiency and economic viability. Ethylene, a key component in producing plastics and fuels, currently sells for about $1,000 per ton, presenting a benchmark for the new technology’s cost-effectiveness.
Electrochemical conversion by using a gas diffusion electrode involves intricate balancing of hydrophobicity and conductivity. Traditional materials tend to compromise either conductivity or hydrophobicity, which is essential to prevent electrolyte leakage during the conversion process.
Rufer and Varanasi’s innovation integrates copper wires into PTFE sheets, resulting in a material that meets both criteria effectively.
“This work really addressed this challenge, as we can now get both conductivity and hydrophobicity,” Varanasi added.
To demonstrate the scalability of their new electrode design, the team successfully created a prototype 10 times larger than typical lab-scale samples without losing performance efficiency. They also developed a model capturing the spatial variability in voltage and product distribution due to ohmic losses, leading to an optimized spacing of conductive wires.
Real-world applications require even larger electrodes, possibly 100 times bigger than lab versions. The researchers’ solution of integrating conductive wires will be crucial for making such large-scale systems practical.
“You can sew this micrometric copper wire into any gas diffusion electrode you want, independent of catalyst morphology or chemistry,” Rufer said in the news release, highlighting the versatility of their approach.
The team ran tests on the new electrode continuously for 75 hours, observing minimal performance degradation, which indicates robustness and practical feasibility. Additionally, the manufacturing process for incorporating the wire can seamlessly integrate into existing large-scale production methods.
“Given that we will need to process gigatons of CO2 annually to combat the CO2 challenge, we really need to think about solutions that can scale,” Varanasi added. “Our hierarchically conductive electrode is a result of such thinking.”
This research marks a significant step forward in CO2 conversion technology, offering a scalable solution with the potential to make a substantial impact on reducing global greenhouse gas emissions.