First-principle study of electronic properties, carrier mobility and quantum capacitance of M-doped Sc2CO2 (M=Ag, Au, Cu, Pd, Pt, Rh) MXenes for supercapacitor electrodes

The doping of transition metals can significantly engineer electronic properties of MXenes. The electronic properties, effective mass, and quantum capacitance of M-Sc2CO2 (M = Ag, Au, Cu, Pd, Pt, Rh) are studied by density functional theory (DFT). M-Sc2CO2 (M = Ag, Au, Cu, Rh) are magnetic semiconductors, with magnetic moments ranging from 0.52 to 0.76 mu B. Atomic reconstruction because of TM doping produces flat bands in doped systems. Pd-Sc2CO2 has the smallest bandwidth of flat bands of 1.8 meV, while Rh-Sc2CO2 has the largest bandwidth of flat bands of 109.9 meV. Compared with Sc2CO2, the doping of Pd and Pt are favor for slow diffusion and the doped systems have higher recombination rate. Drastic increase of m*e for the doping of Ag, Au, and Cu in spin-down channel results in the slow diffusion in conduction band and induces the larger recombination rate. All systems are potential cathode materials due to much larger top Cdiff and Q in negative bias than that in positive bias.