Determination of Possible Reversible Lithium Plating through Electrochemical Analysis at 30°C in Lithium Ion Cells

摘要

Fast charging of lithium ion cells is an important hurdle to overcome for the increased penetration of electric vehicles into the transportation market. During the fast charging of lithium ion cells with today's current negative electrode active materials, namely graphite, lithium metal plating has a high likelihood of occurring. This occurs as most of the lithiated graphite potential is within 100 mV of Li/Li~+ potential where a small polarization can result in lithium metal plating on the negative electrode. This plating leads to safety issues, and capacity fade, among other things. As the lithium metal is plated on the graphite negative electrode it can either become isolated and inactive, resulting in a loss of active lithium and capacity fade in the cell, or the lithium remains active during cell cycling where it may either migrate into the negative electrode over time or travel to the cells positive electrode during discharge.