The anode performance of several kinds of carbonaceous materials used for lithium-ion batteries has been examined in a non-aqueous electrolyte containing Li+ cation, where the test electrode was fabricated by sandwiching the carbon fiber sample between Ni grids without using any binder or any other additives. When the carbon surface was cleaned by a heat-treatment, a very sharp peak has been found to appear at a potential slightly more positive than 0 V versus Li \ Li+ on the positive charge branch of the cyclic voltammogram of the test electrode. We examined in detail the condition of the peak＇s appearance by varying the source of carbon and the surface treatment process. With an appropriate surface pre-treatment condition, the peak could be observed with any carbon sample irrespective of the interior structure of the carbon. An active carbon fiber sample revealed an extraordinarily large peak. Such a surface sensitive nature of the peak suggests that it could be attributed to a Faradaic adsorption of lithium on the carbon surface.