An electrode assembly that includes a current collector, a lithium foil, and a solid solution interface that chemically binds the current collector and the lithium foil is provided. The solid solution interface includes a portion of the current collector that is impregnated with lithium atoms diffused from the lithium foil. In some variations, a method for forming the electrode assembly includes heating a precursor electrode assembly that includes a current collector and a lithium metal film to a temperature that is less than a melting point of lithium, so that lithium atoms diffuse into the current collector during the heating. In other variations, a method for forming the electrode assembly includes disposing a molten lithium onto a heated current collector to form a precursor electrode assembly, and cooling the assembly to form a lithium metal layer that is chemically bonded to the current collector.