Pacific Northwest National Laboratory
Richland, WA 99352
Innovation Center for Battery500 Consortium*
Li-ion batteries are the leading technology for consumer electronics, computation and commpunication devices, electric vehicles and grid scale energy storage. The performance of Li-ion batteries has been steadily improved with a drastic reduce in the cost. However, it is recognized that further increase in energy density to more than 300 Wh/kg will be difficult based on the currently used electrode materials. The most promising approach to achieve a much higher energy density and to reduce the cost to less than $100/kWh is to enable the utilization of Li metal anode in future batteries. A careful analysis suggests that when coupled with a Li metal anode, both high Ni (nickel) NMC (nickel manganese cobalt oxide) and S (sulfur) systems can achieve an energy density of 500 Wh/kg. The 500 Wh/kg battery requires materials and components to be optimized on a system level to allow high efficiency utilization of the active materials (high utilization). Several scientific and technological challenges need be addressed, including: (1) enabling high efficiency utilization of Li metal anode (less than 200% excess Li compared to the cathode capacity), (2) increasing active materials loading, reducing parasite mass and inactive components, (3) improving packing density and ion transport in thick electrodes, (4) increasing the stability window, and (5) reducing undesirable interfacial reactions and cross contamination between electrodes. Under high utilization conditions, the fundamental failure mechanisms also differ from the experimental conditions widely studied in the literature. A combination of strategies are explored to address the Li metal challenge, including new electrolytes to depress dendrite formation and increase metal deposition/stripping efficiency, polymer or composite materials to control Li deposition, surface coatings and solid state electrolyte to reduce SEI formation, and non-flammable electrolytes to improve safety. Electrode architectures also play a critical role. Three-dimensional architectures are developed to improve the stability of both the cathode and anode. Progresses in both NMC and S systems will be discussed.
*The Battery500 Consortium is a $50M, multi-institute program supported by the Office of Energy Efficiency & Renewable Energy of the US Department of Energy. The partners are Pacific Northwest National Laboratory, Brookhaven National Laboratory, Idaho National Laboratory, University of Washington, Binghamton University, Stanford University/SLAC, University of Texas Austin, University of California San Diego.