Solid Electrolyte Protected LI Metal Electrodes
Demand for Lithium-ion (Li-ion) batteries has increased significantly as products such as smartphones, laptops, electric vehicles, and grid storage batteries rise in popularity. However, Li-ion batteries have numerous safety and performance limitations due to their flammable electrolyte and the charge storage density of their active materials, which are not easily overcome by incremental progress. New types of high-performance separators and electrodes built with solid-state ion conductors could simultaneously improve the energy density and safety of lithium ion batteries by removing the most flammable battery components, and also improving the driving range and durability of electric vehicles. Solid-state separators also open the door to the use of lithium metal as an active material, resulting in a significant increase in cell energy content, and the subject of research efforts for the past several decades. New battery technology that employs energy dense, thermally stable, and long-lasting materials will also be of interest for grid storage, particularly in dense, urban environments where the space occupied by storage systems is more of a concern.
Project Innovation + Advantages:
PolyPlus Battery Company, in collaboration with SCHOTT Glass, will develop flexible, solid-electrolyte-protected lithium metal electrodes made by the lamination of lithium metal foil to thin solid electrolyte membranes that are highly conductive. Past efforts to improve lithium cycling by moving to solid-state structures based on polycrystalline ceramics have found limited success due to initiation and propagation of dendrites, which are branchlike metal fibers that short-circuit battery cells. A major benefit of the PolyPlus concept is that the lithium electrode is bonded to a "nearly flawless" glass surface which is devoid of grain boundaries or sufficiently large surface defects through which dendrites can initiate and propagate. These thin and flexible solid electrolyte membranes will be laminated to lithium metal foils, which can then be used to replace the graphite electrode and separators in commercial Li-ion batteries. The team's approach is based on electrolyte films made by commercial melt processing techniques, and they will work in close cooperation to develop compositions and processes suitable for high-volume, low-cost production of the lithium/glass laminate. The SCHOTT team will focus on glass composition and its relationship to physical properties while the PolyPlus team will determine electrochemical properties of the glass and provide this information to SCHOTT to further refine the glass composition. PolyPlus will also develop the Li/glass lamination process and work with the SCHOTT team on manufacturing and scale-up using high volume roll-to-roll processing.
If successful, developments made under the IONICS program will increase the energy storage content for vehicle batteries by about 30% compared to today's Li-ion batteries and significantly reduce battery storage system costs.
IONICS program innovations could contribute to energy storage solutions for transportation and the grid, lessening U.S. dependence on imported oil and improving grid resilience.
A 10% increase in electric vehicle use would reduce US oil consumption by 3% and reduce total US CO2 emissions by 1%.
IONICS program innovations could further establish U.S. businesses as technical leaders in energy storage, encouraging greater use of readily available renewable resources and increasing the competitiveness of electric vehicles.