Surface State Change of Lithium Metal Anode in Full Cell during Long Term cycles

In order to investigate the surface state change of the lithium metal anode during long term cycles, a laminate-type lithium metal rechargeable battery was fabricated from a lithium foil, a Li4Mn5O12 electrode, a polyimide (PI) membrane having a three-dimensionally ordered macroporous structure (3DOM) and a 1 mol dm(-3) LiPF6 ethylene carbonate (EC) solution as an anode, a cathode, a separator and an electrolyte, respectively. After the charge/discharge cycles, the chemical composition at the surface of the lithium metal anode taken from the laminate cell was investigated by X-ray photoelectron spectroscopy (XPS). Decomposition products of electrolyte, e.g. Licontaining organic compounds, LiF or -PO4 were accumulated on the lithium metal surface during long-term charge/discharge cycles. The accumulation of the decomposition products causes the increase of the lithium ion transport resistance of the battery, resulting in the inhibition of dissolution and deposition of lithium which is associated with drop of capacity. (C) The Electrochemical Society of Japan, All rights reserved.