Enhancement of the corrosion resistance of nickel-plated copper used for lithium-ion battery tabs with multilayer electroless coatings

The traditional electrode tabs may not adequately meet the needs of high energy density lithium-ion batteries used in electric vehicles due to their poor corrosion resistance. In this study, multilayer nickel coatings with different phosphor contents and alloying elements were prepared by electroless plating, and then their structure, composition, resistivity and corrosion resistance were characterized by scanning electron microscopy, metalloscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and electrochemical measurements. The obtained multilayer coated sample is resistant to electrochemical corrosion by restricting electrochemical corrosion to the middle layer because of the potential difference, and the outer nickel-chromium-phosphor layer is highly resistant to chemical corrosion due to the high phosphor contents. In conclusion, the multilayer coatings show excellent electrochemical corrosion resistance and conductivity, the corrosion current is 7.674 × 10−6 A/cm2 and the weight loss is only 0.896% after immersion in electrolyte for 168 h. These excellent properties make nickel-plated copper suitable for use as lithium-ion battery tabs.