DFT-Driven Insights into the Electronic, Magnetic, and Transport Properties of 2D Nb₃C₂ MXene for High-Performance Li-Ion Batteries

Abstract

The Two-dimensional material ‘MXene’ has attained significant attention for its outstanding characteristics inherent to nanostructures. However, to date, Nb₃C₂ MXene, particularly in Cr-doped form, has not been theoretically explored for Li-ion battery applications. In this work, First-principles calculations were performed to explore the structural, electronic, magnetic and transport properties of newly designed pristine Nb₃C₂ and Cr-doped Nb₃C₂ along with their energy storage potential, using the FP-LAPW approach. Electronic properties, including band structure and density of states indicate metallic behavior in both structures with an indirect band gap, fulfilling a key requirement for electrode materials in energy storage systems. Pristine Nb₃C₂ exhibits an essentially non-magnetic ground state, while Cr-doped Nb₃C₂ reveals ferromagnetic behavior. Theoretical capacities of 169 mAh/g for pristine Nb₃C₂ and 280mAh/g for Cr-doped Nb₃C₂ were obtained, indicating a substantial enhancement upon Cr doping and exceeding that of pristine Nb₂C (170mAh/g) reported in literature. The predicted electrochemical properties unveil that both pristine and Cr-doped Nb₃C₂ possess favorable open-circuit voltages within the desirable range for anode materials, along with high electronic conductivity and improved gravimetric capacity. Furthermore, transport property analysis based on semi-classical Boltzmann theory highlights their promising thermoelectric behavior, complementing their electrochemical performance and providing a comprehensive evaluation of MXene in energy storage devices.