XPS study of duplex stainless steel as a possible current collector in a Li-ion battery

► Duplex stainless steel work as current collector in Li-ion battery between 3 and 4.5 V. ► Li reacts with metal-oxides/hydroxides on the steel surface during cathodic sweeps. ► The PF6− anion reacts with the metals in the steel forming metal fluorides. ► Passive layer thickness under the SEI is similar to that formed in an aq. solution.