Deep Dive into Lithium-Ion Cells with High Energy and High Voltage
Although invented in the 1970s and widely available commercially, lithium-ion batteries are still limited to about 65% of their theoretical energy density in practical application. So there is considerable room for improvement.
In a multi-laboratory project, Argonne along with Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, and National Renewable Energy Laboratory, is seeking to limit the degradation that occurs at material surfaces within these batteries when operated at higher voltages than the standard 4.2 volts. Enabling operation at higher voltage is essential to realizing energy storage targets for next-generation lithium-ion cells. However, a lack of knowledge on the fundamental physics governing high-voltage operation has been a critical barrier to progress.
Goals of this “deep dive” project are to gain a fundamental understanding of the atomic- and molecular-scale mechanisms that govern the failure of battery materials and interfaces under high-energy and high-voltage conditions. Major thrusts are in the areas of advanced theory and synthesis of model systems, development of electrolytes and electrolyte additives as well as electrode materials and surface modifications that allow high-voltage operation, and electrochemical modeling and diagnostics of cell behavior.
Because this is a multi-laboratory effort, key to success is the development of standardized procedures for the assembly and testing of research cells of different sizes and designs. These procedures detail physical parameters such as electrode areas and electrolyte volume, as well as charge-discharge cycling procedures and data analysis methods needed for consistent and effective communication of the experimental data.
The project seeks to bring together diverse expertise from across the DOE complex and the many advanced characterization techniques at facilities such as the Advanced Photon Source to bring new insights into the challenges of next-generation battery materials.