A method of manufacturing a composite metal foil includes providing a first metal layer and forming a second metal layer on a surface of the first metal layer through electroplating. The first metal layer is copper foil, nickel foil, stainless steel foil, or a combination thereof. A contact angle of a surface of the second metal layer to liquid lithium metal is lower than 90 degrees.

A structure includes an Sn layer or an Sn alloy layer formed above a substrate, and an under barrier metal formed between the substrate and the Sn layer or Sn alloy layer. The under barrier metal is an Ni alloy layer containing Ni, and at least one selected from W, Ir, Pt, Au, and Bi, and can sufficiently inhibit generation of an intermetallic compound through a reaction, caused due to metal diffusion of a metal contained in the substrate, between the metal and Sn contained in the Sn layer or Sn alloy layer.