Electronic Transport in two-dimensional 2D- MXenes for Energy Storage

Two-dimensional flexible supercapacitors may offer environment-friendly energy storage for high-power usage. MXenes, are a new family of 2D materials with a general formula of Mn+1XnTx where M is a transition metal, X is carbon and/or Nitrogen, and T represents the surface terminations group (O, F, OH). This 2D hexagonal family has been shown to be a potential electrode material for SCs, due to its large active surface area, and excellent electrical conductivity. In this work, we investigate the electronic and vibrational properties of pristine Ti3C2 and fully terminated (Ti3C2F2, Ti3C2(OH)2, Ti2CF2) using first-principles calculations. Our goal is to understand how the electronic transport properties depend on the chemical composition and surface termination using density functional theory (DFT), density functional perturbation theory (DFPT), and the linearized Boltzmann transport equation (LBTE) within the relaxation time approximation (RTA). We present a detailed study of the convergence behavior of the electrical conductivity in these systems, we compare the different levels of approximations and discuss techniques to reduce the computational cost of our calculations.