LLNL’s 3D Printed Electrodes Could Convert CO2 to Renewable Energy

Scientists and engineers at Lawrence Livermore National Laboratory (LLNL) are now 3D printing flow-through electrodes (FTEs), which are critical components in electrochemical reactors. Electrochemical reactors can convert carbon dioxide into a renewable source of energy while significantly reducing carbon emissions. With the design freedom afforded by 3D printing, scientists are able to create shapes and pathways they never could before, thus maximizing reactor performance.

Electrochemistry has seen a boom within the last decade from both industry scientists and academics. Electrons can act as traceless agents during redox chemistry, effectively relieving the need to use toxic or hazardous reductants. Similar to how the world has begun harvesting electricity from solar and wind energy, thus reducing greenhouse gas emissions from fossil fuels, so too does the electrification of the chemical industry provide the opportunity to locally create commodity materials without having to store, transport, or waste hazardous chemicals.

Traditional materials used in FTEs, such as carbon fiber foams and felts, have a disordered structure and cannot be easily modified. In turn, these materials suffer from uneven flow. The mass transport distribution, and adoption of this technology on a commercial scale is dependent upon efficiency of mass transfer. However, 3D printing with advanced materials, such as carbon aerogels, has provided scientists from LLNL the ability to create a macrostructure with novel geometries, including porous designs.

With direct ink write 3D printing, the LLNL team was able to design flow channel geometry within electrodes that enhanced electrochemical reactions. 3D printed lattice structures were able to improve mass transfer by one to two times compared to traditional materials, according to the researchers.

“By 3D printing advanced materials such as carbon aerogels, it is possible to engineer macroporous networks in these material without compromising the physical properties such as electrical conductivity and surface area,” said Swetha Chandrasekaran, co-author of the LLNL study, published in Proceedings of the National Academy of Sciences.

“For the first time, Lawrence Livermore National Laboratory engineers have 3D printed carbon flow-through electrodes (FTEs) from graphene aerogels. By capitalizing on the design freedom afforded by 3D printing, researchers demonstrated they could tailor the flow in FTEs, dramatically improving mass transfer – the transport of liquid or gas reactants through the electrodes and onto the reactive surfaces.” Illustration by Veronica Chen/LLNL.

As scientists gain control and predictability over 3D printed electrodes, they could provide vital to the global energy crises and pave the way to scaled-up reactors and high-efficiency electrochemical converters.

“Gaining fine control over electrode geometries will enable advanced electrochemical reactor engineering that wasn’t possible with previous generation electrode materials,” said co-author Anna Ivanovskaya. “Engineers will be able to design and manufacture structures optimized for specific processes. Potentially, with development of manufacturing technology, 3D-printed electrodes may replace conventional disordered electrodes for both liquid and gas type reactors.”

Engineers and scientists at Lawrence Livermore National Laboratory are still exploring all possibilities this technology has to offer, such as the conversion of carbon dioxide into other fuels or polymers. Electrochemical energy storage has the possibility to produce electricity from carbon-free and renewable resources. Currently, their mission is to produce higher resolution electrodes with light-based 3D polymer printing techniques such as micro-stereolithography and two-photon lithography.