Study of Electroless Nickel Plating on Super Duplex Stainless Steel for Lithium-Ion Battery Cases: Electrochemical Behaviour and Effects of Plating Time

Abstract

With increasing demand for Li-ion batteries, studies are focusing on enhancing battery performance and safety. However, studies on battery cases remain scarce. Herein, we propose the use of super duplex stainless steel SAF2507, which is a two-phase (austenite + ferrite) steel, for battery casings. Unlike conventional AISI304, SAF2507 maintains its corrosion resistance and strength at high temperatures and precipitates a secondary phase at approximately 975 °C. However, the effects of Ni plating on this secondary phase are not well documented. Therefore, the electroless Ni plating of SAF2507 after secondary-phase precipitation was studied. Briefly, heat treatment at 1000 °C was used to induce precipitation, and the electroless Ni plating behaviour over varying plating periods was analysed using open-circuit potential, potentiodynamic polarisation, and electrochemical impedance spectroscopy measurements. The plating state and corrosion behaviour were examined using scanning electron microscopy. Heat-treated SAF2507 steel with a secondary phase exhibited excellent electroless Ni plating behaviour, which enhances the safety and durability of Li-ion batteries. Furthermore, uniform plating and electrochemical behaviour were achieved after 180 s, suggesting that SAF2507 is superior to AISI304. These findings contribute to the development of safer and more efficient batteries and address the growing demand for Li-ion battery case materials.

Crystallization of Secondary Phase on Super-Duplex Stainless Steel SAF2507: Advanced Li-Ion Battery Case Materials

“…Owing to its high-alloy chemical composition, SAF2507 is adjusted and cast in electric furnaces [28,29]. In this study, SAF2507 castings produced in an electric furnace were used.…”

“…XRD patterns provide information on the phases based on the patterns of the diffraction angles, allowing for the determination of the presence of secondary phases. XRD analysis identifies secondary phases as Sigma, Chi, and CrN [29,35]. Although Sigma and Chi were easily distinguishable phases, CrN (size of 0.2 µm) precipitated in fine spherical forms, making it less discernible using FE-SEM analyses.…”

Effect of Secondary Phase on Passivation Layer of Super Duplex Stainless Steel UNS S 32750: Advanced Safety of Li-Ion Battery Case Materials

“…Among duplex stainless steels, the super duplex stainless steel (SDSS) with a pitting resistance equivalent number (PREN) of 42 showcases outstanding strength and corrosion resistance. It also maintains high-temperature strength exceeding 300 MPa at 700 °C and a low thermal-expansion coefficient (13.5 × 10 −6 ppm/°C) [ 20 , 21 , 22 ]. These attributes significantly enhance the safety of Li-ion battery casings.…”