Provided is a secondary battery having an electrode assembly sealed in the interior of a battery case together with an electrolyte, the electrode assembly comprising: one or more cathodes each having cathode tabs which are not coated with cathode active material; one or more anodes each having anode tabs which are not coated with anode active material; and one or more separation films interposed in between the cathode and anode, wherein the cathode tabs and the anode tabs are connected, respectively, to cathode leads and anode leads protruding externally from the battery case, and one or more electrode terminals selected from the group consisting of the cathode tabs, anode tabs, cathode leads and anode leads are made of wood's metal.