Optimizing Lithium-Silver Alloy Phases for Enhanced Energy Density and Electrochemical Performance

Lithium (Li) metal batteries though with high energy density are still facing issues like Li dendrite growth, dead Li formation, and thick solid electrolyte interphase (SEI), hindering their long-term stability. Recently, Li-Ag alloys are reported to potentially address these challenges possibly due to their conductivity, lithiophilicity, and mechanical stability. In the pursuit of high energy density batteries, Li-Ag alloys typically employ high Li content phase (γ1). In this study, we employed density functional theory (DFT) calculations to compare the thermodynamic stability, Li adsorption, and Li diffusion property of Ag-rich Li-Ag alloy within the γ1 phase (AR-γ1), Ag-poor Li-Ag alloy within the γ1 phase (AP-γ1), and pure Li. AR-γ1 showed better thermodynamic stability and improved Li adsorption and diffusion property compared to AP-γ1 and pure Li. Electrochemical tests further confirmed the advantages of AR-γ1 in terms of electrode kinetics and cycling performance compared to pure Li. Our study offers guidance in selecting high energy density alloy phases for Li-Ag alloys.