Researchers are exploring ways to capture carbon dioxide and convert it into valuable products to reduce greenhouse gas emissions. A breakthrough by engineers at MIT has resulted in a new electrode design that increases the efficiency of converting carbon dioxide into useful chemicals. The team focused on converting carbon dioxide into ethylene, a common chemical used in plastics and fuels. The new design could also be applied to produce other high-value chemicals like methane and methanol. The goal is to produce these chemicals cost-effectively to compete with the current market prices.
The electrode design developed by the team addresses a key challenge in electrochemical conversion systems. The materials used in the gas diffusion electrodes must balance conductivity and water repelling properties to optimize performance. The team found a solution by incorporating conductive copper wires into a thin sheet of PTFE (Teflon), combining conductivity and hydrophobicity. By weaving the wires through the material, the researchers were able to create smaller subsections that act as more efficient electrodes, allowing for improved electron transfer and reduced energy consumption.
Scaling up the electrode design is crucial for real-world industrial applications. The team produced a larger sheet of electrodes to demonstrate its effectiveness and efficiency. They found that conductivity drops off significantly with size, leading to higher energy requirements and increased costs. By incorporating conductive wires into the material, the researchers were able to counteract the drop in conductivity and optimize the performance of the electrode. This approach allows for the production of larger electrodes without sacrificing efficiency.
The researchers developed a model to analyze the spatial variability in voltage and product distribution on electrodes due to ohmic losses. This model, along with experimental data, helped optimize the spacing of conductive wires to improve overall performance. The electrode system proved to be robust, as a test electrode ran continuously for 75 hours with minimal changes in performance. The weaving process for adding the conductive wires can be easily integrated into existing manufacturing processes, making it scalable for industrial applications.
The ability to scale up the electrode design is crucial for addressing the challenge of processing gigatons of carbon dioxide annually to combat climate change. The hierarchically conductive electrode developed by the research team is a result of innovative thinking and a focus on identifying critical bottlenecks to develop impactful solutions. The approach of incorporating conductive wires into gas diffusion electrodes can be applied across different catalysts and electrode designs. The research was supported by Shell through the MIT Energy Initiative.
Overall, the new electrode design offers a practical and cost-effective solution for converting carbon dioxide into valuable chemicals. By overcoming the tradeoff between conductivity and hydrophobicity, the team has developed a scalable system that can be integrated into industrial processes. The research represents a significant step forward in addressing the challenge of reducing greenhouse gas emissions through the conversion of carbon dioxide into useful products.
