Fast charging of Li-ion cells: Effect of separator membranes and mapping of “safe lines” to avoid Li plating

An experimental method is introduced that uses microprobe Li/Cu reference electrodes to map “safe” charging regimes avoid Li metal plating on graphite anodes at rates 8C. With this method, a Li-ion cell closely approaches the condition but avoids descending into regime. This approach used demonstrate effects of microporous separator in cells consisting layered nickel-manganese-cobalt oxide cathode and anode. We argue most difference behaviors for different separators arises from time delayed Li+ ion percolation through membrane. Our study suggests explicitly treating kinetics phase transitions lithiated anode essential electrochemical models predicting lines fast cells.