According to embodiments of the present application, an electrode tab is provided comprising a substrate, a protective layer located outside the substrate, wherein the protective layer includes a first non-metallic element and a first metal element and the atomic ratio between the first non-metallic element and the first metal element is in the range of 10% to 30%. The embodiments of the present application further provide an electrode assembly and a battery. The object of the present application is to provide an electrode tab, an electrode assembly and a battery so as to at least achieve the improvement of electrolyte resistance under the immersion of electrolyte.