Fluorine-Terminated MXene as an Anode Material for Dual-Ion(Ca<sup>2+</sup>/Mg<sup>2+</sup>) Batteries with Rapid Diffusion Mobility
Rahulkumar P. Jadav, Deobrat Singh, Rajeev Ahuja, Yogesh Sonvane
Abstract
Discovering thin and high-ion transfer mobility electrode materials is necessary to boost the charge–discharge rate of rechargeable metal-ion batteries. The functionality of two-dimensional (2D) MXenes as anode materials is largely dependent on their surface terminal groups, and surface terminal techniques are frequently employed to enhance their charge–discharge performance. Here, we construct F-terminated Hf 3 C 2, while we use the first-principles calculations to explore its potential as an anode material for rechargeable metal-ion batteries, such as Mg- and Ca-ion batteries. The metallic nature and significant structural stability of the Hf 3 C 2 F 2 monolayer found by phonon and thermal properties assessed with ab-initio molecular dynamics (AIMD) and the machine learning force field (MLFF) and the low average open-circuit voltage (OCV) of 0.591 and 0.394 V and relatively low diffusion energies of Mg 2+ and Ca 2+ ions of 0.077 and 0.143 eV, respectively, can help improve the battery cycle. These multivalent metal cations have very low OCV values and very modest diffusion barriers, allowing the Hf 3 C 2 F 2 monolayer to be a feasible anode material for rechargeable dual-ion batteries.