The Importance Of Nanomaterials In Gms All-Electric Future

Mei Cai, Director, Battery Cell Systems Research, General Motors

A s we at GM continue to build out a lineup of fully electric vehicles, it’s essential that we grow and apply our scientific expertise in nanomaterials to develop and manufacture these critical materials. Various definitions of a nanomaterial have emerged from industry, government, and standards organizations. Perhaps one of the more compelling of these is from the International Organization for Standardization (ISO): “a material with any external dimension in the nanoscale or having internal structure or surface structure in the nanoscale.” Here, “nanoscale” covers 1-100 nanometers, where 1 nanometer is one billionth of a meter. Common things with at least one dimension in the nanoscale range are a glucose molecule (~1 nm), a DNA strand (~2 nm), and quantum dots (1-10 nm): all are too small to see with the unaided human eye.

Nanomaterials, which are most relevant to our business as key components of our battery cells, are typically synthesized in powder form and then applied as “slurries” onto metallic current collectors during battery cell manufacturing.

For example, our negative electrode material, or anode, is typically graphite consisting of stacked layers of graphene. Alternatively, positive electrode materials for our cathodes consist of transition metals such as nickel, cobalt, and manganese, as well as aluminum. 

Because of their “open” nanoscale structures, Li ions can easily move in and out of them as part of a sequence of electrochemical reactions that enable the cell to power a vehicle.

My team of about 70 electrochemists, materials scientists, physicists, and chemical and mechanical engineers in GM’s Research and Development labs in Warren, Michigan, are hot on the trail of new battery chemistries that hold great promise for future GM EVs. My team experiments with different types of nanomaterials every day, comprising everything from ironbased cathodes to silicon anodes.

It’s incredible to think that today’s Ultium-powered EV vehicles, such as the GMC HUMMER EV and Cadillac LYRIQ, are powered by something so small. While our Ultium propulsion technology can power an entire portfolio of EVs, we’re not stopping there.

"It’s incredible to think that today’s Ultium-powered EVs vehicles such as the GMC HUMMER EV and Cadillac LYRIQ are powered by something so small. While our Ultium propulsion technology can power an entire portfolio of EVs, we’re not stopping there"

Our experimental capabilities are world-class. For example, we can perform forensics on different cells at the nanoscale using tools such as atomic layer deposition microscopes. This lets us analyze small, subtle changes within the structure of a cell without having to take the cell apart, allowing us to continue experiments without disruption. We are also applying state of-the-art computational tools that enable us to manipulate the atomic structures of battery anode and cathode materials with computer algorithms that can suggest new nanomaterials that no one has previously thought of.

My experimental and modeling teams are closely integrated, and this is part of our secret to success. Everything that my team does is motivated by our end goal: produce batteries that provide great value for our customers while also meeting our vehicle requirements.

In addition to studying existing and future battery cell chemistries, we also search for ways to more effectively commercialize them. Within our R&D labs, we can even produce prototype battery cells, albeit at the small rate of less than 10 meters per minute (compared to more than 50 meters per minute for a commercial cell operation). This fusion of our nanomaterial knowledge and LGES’ cell-making capabilities will lead to even better results at our joint venture in the future as we scale this technology.

The experience that we gain every day in both our R&D labs and production facilities is supplemented by knowledge we leverage from the external technical community through venture capital investments. Examples of GM Ventures’ portfolio companies that specialize in nanomaterials include Mitra Chem, who will help us accelerate the work we’re already doing on nextgeneration, iron-based cathodes for more affordable EVs through their AI-based platform and labs. GM and OneD Battery Sciences also executed a joint research development agreement focusing on the potential application of OneD’s SINANODE nanotechnology, which adds more silicon to the anode battery cells by fusing silicon nanowires into EV-grade graphite.

The EV space, in general, is still very much an emerging field, and to stay at the forefront of this dynamic space, we every day apply the might of our corporate and leveraged resources to the out-of-the-box thinking needed for future GM EVs. A testament to this is GM R&D’s 2,000-plus electrification-related patents. Our inventive capabilities, combined with 116 years of manufacturing know-how and demonstrated experience in scaling technology, give me confidence that we’re on the right track.