19AUGUST 2024CXINSIGHTSADVANCED MATERIALS FOR CLEAN ENERGY APPLICATIONSOver the course of the 100+ year history of the automotive industry, ground transportation vehicles were largely powered through the combustion of gasoline in internal combustion engines. The advent of the automotive industry liberated people from the horse and buggy and fostered the growth of urban populations. However, humanity now finds itself facing one of its most significant threats: anthropogenic climate change due to greenhouse gas emissions. According to the U.S. EPA, 4.6 metric tons of CO2 are emitted from the tailpipe of a "typical passenger vehicle" in a single year, along with smaller amounts of CH4 and N2O.General Motors is working to help achieve a "zero emissions" future with fully electric vehicles. The IC engine, gas tank, transmission and exhaust, the main components of IC propulsion systems, are now being replaced with power electronics, motors and batteries which produce no tailpipe emissions. As we at GM continue to build a lineup of fully electric vehicles, it's essential that we grow and apply our scientific expertise in advanced materials to batteries on our journey to a zero emissions future.The ubiquitous lithium-ion battery is based on a graphite anode, which is the mainstay material in our batteries. This graphitic anode material is essentially stacked layers of graphene. An alternative to graphite is a so-called "blended" anode, where graphite is combined with small quantities of silicon oxide.Alternatively, positive electrode materials for our cathodes consist of transition metals such as nickel, cobalt and manganese as well as aluminum. Common cathode materials are designated as NCM and NCMA (N=nickel, C=cobalt, M=manganese, A=aluminum). These materials are typically synthesized in powder form and then applied as "slurries" onto metallic current collectors during battery cell manufacturing. Because of their "open" crystal structures, Li-ions can easily move in and out of the anode and cathode materials as part of a sequence of electrochemical reactions that enable the cell to power a vehicle.By Mei Cai, Director, Battery Cell Systems Research, General Motors
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