Understanding the Lithiation of the Sn Anode for High-Performance Li-Ion Batteries with Exploration of Novel Li–Sn Compounds at Ambient and Moderately High Pressure

Volume expansion and elastic softening of the Sn anode on lithiation result in mechanical degradation and pulverization of Sn, affecting the overall performance of Li–Sn batteries. It can, however, be overcome with the help of void space engineering by using a LixSn phase as the prelithiated anode, where an optimal value for x is desired. Currently, Li4.25Sn is known as the most lithiated Li–Sn compound, but recent studies have shown that at high pressure, several exotic and unusual stoichiometries can be obtained that may even survive decompression from high-to-ambient pressure with improved mechanical properties. With a belief that hydrostatic pressure may help in realizing Li-richer (x > 4.25) Li–Sn compounds as well, we performed extensive calculations using an evolutionary algorithm and density functional theory to explore all stable and low-energy metastable Li–Sn compositions at pressures ranging from 1 atm to 20 GPa. This not only helped us in enriching the chemistry of a Li–Sn system, in general,...