The Quest for the Next Gen: Metal Fluoride Cathodes
July 11, 2014 – Charged Electric Vehicles Magazine – The current generation of lithium-ion battery materials is quickly approaching its theoretical limit. In commercial layered oxide cathodes, like the popular nickel-manganese-cobalt (NMC), there is only one lithium ion for every metal. So, the most energy you could possibly store with those materials is one full lithium in and out, or about 300 mAh per gram of cathode. Today’s commercially available cells are cycling about 0.6 to 0.7 lithium ions per metal, and the market is steadily increasing that ratio by using more nickel- and manganese-rich compositions. Industry insiders report seeing several materials that are closer to 0.8 to 0.9 lithium ions per metal, and the lithium-rich NMC materials -pioneered by Argonne National Laboratory – are basically cycling the full amount of lithium. In other words, the headroom for improvement is quickly dropping.