Structural, Electronic and Magnetic Properties of 2D MXene Monolayer for Energy storage applications. A Computational Investigation /

Abstract

Two-dimensional material ‘MXene’ has attained a lot of attention of scientists for its outstanding and amazing properties. In this study, structural, electronic, magnetic and transport properties of Nb3C2 and Cr-doped Nb3C2 along with their energy storage applications are calculated using the FP-LAPW approach. The calculated crystal structure of Nb3C2 and Cr-doped Nb3C2 reveals that compounds possess hexagonal and orthorhombic crystal structure with p63mmc and pmm2 space group respectively. The calculated band gap for both compounds with GGA-PBE and GGA+U indicate metallic behavior with an indirect band gap. Whereas the DOS calculations reveales the similar conclusion as that for band structure. It is also found that there exists a strong covalent bonding between Cr-C, while mixture of covalent and ionic bonding among Nb and C atom in Nb-C and Cr doped Nb3C2. Magnetic properties are calculated with sp-GGA and sp-GGA+U, where U=3 eV for Nb-4d orbitals and U= 2eV for Cr-3d orbitals. Pristine Nb3C2 exhibits ferrimagnetic nature while Cr-doped Nb3C2 also revealed ferromagnetic behavior. To investigate the transport properties i.e, figure of merit (ZT), Seebeck coefficient, power factor, electrical conductivity and thermal conductivity are calculated with Boltztrap 2. This thesis focuses on investigation of electrochemical performance of both compounds using discharge voltage and gravimetric capacitance. Both materials revealed as novel electrode for Li+-ion batteries due to their higher electronic conductivity, less required voltage and improved gravimetric capacity.