Lithiation Analysis of Metal Components for Li-Ion Battery using Ion Beams

Abstract

Metal components are extensively used as current collectors, anodes, and interlayers in lithium-ion batteries. Integrating these functions into one component enhances the cell energy density and simplifies its design. However, this multifunctional component must meet stringent requirements, including high and reversible Li storage capacity, rapid lithiation/delithiation kinetics, mechanical stability, and safety. Six single-atom metals (Mg, Zn, Al, Ag, Sn and Cu) are screened for lithiation behavior through their interaction with ion beams in electrochemically tested samples subjected to both weak and strong lithiation regimes. These different lithiation regimes allowed us to differentiate between the thermodynamics and kinetic aspects of the lithiation process. Three types of ions are used to determine Li depth profile: $H^+$ for nuclear reaction analysis (NRA), $He^+$ for Rutherford backscattering (RBS), and $Ga^+$ for focused ion beam (FIB) milling. The study reveals three lithiation behaviors: (i) Zn, Al, Sn form pure alloys with Li; (ii) Mg, Ag create intercalation solid solutions; (iii) Cu acts as a lithiation barrier. NRA and RBS offer direct and quantitative data, providing a more comprehensive understanding of the lithiation process in LIB components. These findings fit well with our ab-initio simulation results, establishing a direct correlation between electrochemical features and fundamental thermodynamic parameters.