Electrochemical lithium intercalation reactions occurring in silver-supported graphite anodes were investigated by X-ray photoelectron spectroscopy (XPS), The binding energy of Li(1s) of intercalating lithium was higher than that of lithium metal, which suggests that lithium exists in the form of a positive ion in the graphite layers, The core level of the C(1s) signal of lithium intercalated graphite was higher than that of graphite, which implies that the carbon in lithium-intercalated graphite has a negative charge, This finding agrees with previous XPS studies indicating that carbon has a negative charge in a graphite-intercalation compound produced by a molten lithium intercalation reaction to graphite, Lithium carbonate, lithium fluoride and organic compounds were produced on the graphite surfaces in charge/discharge reactions in 1 M LiPF(6)/EC-DMC electrolytic solution, It was also confirmed that the initial charge current supplied to the graphite electrode with a potential between 2.8 and 0.6 V did not cause a lithium-intercalation reaction. It caused, however, other reactions such as decomposition of the electrolytic solution and production of passivating films. (C) 1997 Published by Elsevier Science S.A.
