Metallic FeSe Monolayer as Anode Materials for Li and and Non-Li Ion Batteries: A DFT Study

By means of density functional theory computations, we explored the electrochemical performance of the monolayer FeSe as anode materials for lithium and non-lithium ion batteries (LIBs and NLIBs). The electronic structure, adsorption, diffusion, and storage behavior of different metal atoms (M) in FeSe were systematically investigated. Our computations revealed that M adsorbed FeSe (M = Li, Na and K) systems show metallic characteristics which give rise to a good electrical conductivity, and mobility with low activation energy for diffusion (0.16, 0.13 and 0.11 eV for Li, Na, and K, respectively) in the transportation of electrons and metal atoms in materials, indicative of a fast charge/discharge rate. In addition, the theoretical capacities of the FeSe monolayer for Li, Na and K reach up to 658, 473, 315 mA h g‒1, respectively, higher than that of commercial graphite (372 mA h g‒1 for Li, 284 mA h g‒1 for Na, 273 mA h g‒1 for K), and the average open-circuit voltage is moderate (0.38~0.88 V for Li, Na and K). All these characteristics suggest the FeSe monolayer is a potential anode material for alkali-metal rechargeable batteries.