arXiv subjects

Sadhana Matth

Publications and source records attributed to Sadhana Matth.

4 recordsLinked to original sources

arXiv2025

Hexagonal BeX (X: S, Te) monolayer as potential electrode material for alkali metal-ion batteries: A DFT perspective

Metal-ion batteries (MIBs) are essential for transitioning to a cleaner and more sustainable energy future. By employing the density functional formalism, we have investigated the hexagonal (h) monolayer of BeS and BeTe as electrode materials for alkali (Li and Na) MIBs. The structural and thermodynamic stability, adsorption of Li/Na atoms, density of states, diffusion, and migration of atoms, as well as capacity, are systematically investigated. The structures of h-BeS and h-BeTe remain stable upon the adsorption of adatoms, resulting in improved electronic conductivity of these monolayers. The climbing image-nudged elastic band calculations estimate a low diffusion barrier of 0.16 eV (0.01 eV) for Li (Na) in h-BeS and 0.20 eV (0.16 eV) for Li (Na) in h-BeTe. Additionally, a maximum storage capacity of 580 mAh g-1 for Li and 1305 mAh g-1 for Na in h-BeS, as well as 174 mAh g-1 for h-BeTe, is estimated for both metal ions.

cond-mat.mtrl-sci↗

arXiv2025

Density functional investigations on 2D-Be2C as an anode for alkali Metal-ion batteries

Metal-ion batteries are in huge demand to cope with the increasing need for renewable energy, especially in automobiles. In this work, we apply first-principle calculations to examine two-dimensional beryllium carbide (2D-Be2C) as a possible anode material for metal-ion (Na and K) batteries. 2D-Be2C is a semiconductor and becomes metallic by adsorbing metal ions. Negative adsorption energy indicates stable adsorption on the monolayer of Be2C. Alkali metal diffusion barrier and optimum path for minimum energy are studied within the framework of the climbing image nudged elastic band method. Here, six intermediate images are considered between the initial and final states. The lowest diffusion barriers for a single adsorbed Na and K atom are 0.016 and 0.026 eV, respectively. A maximum open circuit voltage of around 1 V is computed for K ions, whereas 0.5 V is for Na ions. Also, the maximum storage capacity of the Be2C monolayer is estimated at 1785 Ah/kg.

cond-mat.mtrl-sci↗

arXiv2025

Electronic structure and thermoelectric properties of CoTiSi half-Heusler alloy: Doping overtones

The quest for thermoelectric materials with high figures of merit is an ongoing and significant area of research. In this study, we investigate the thermoelectric properties of the CoTiSi half-Heusler alloy using density functional theory calculations implemented via the Wien2k package. Our approach begins with a thorough structural optimization to determine the equilibrium lattice parameter and the atomic positions of the constituent elements within the unit cell of CoTiSi. Following this, we analyze the thermal transport properties of the alloy under the constant relaxation time approximation, which allows us to gain insights into its thermoelectric performance. Our calculations reveal a substantial Seebeck voltage and thermopower, with notably higher values for P-type doping than N-type doping. This finding highlights the enhanced thermoelectric performance of P-type carriers in this material, providing a starting point for experimentalists to utilize this alloy for real device applications.

cond-mat.mtrl-sci↗

arXiv2024

High-Performance Thermoelectric Properties of Half-Heusler CoHfSi: A First-Principles Study with Temperature-Dependent Relaxation Time

In the ongoing search for innovative thermoelectric (TE) materials with superior TE performance globally, we aim to investigate the possible use of half-Heusler alloy CoHfSi in TE applications. We analyzed the structure stability, thermodynamic inertia and electrical and thermal transport properties using density functional formalism and semi-classical Boltzmann transport theory. Positive phonon frequencies confirm this alloy's dynamical stability, and the Born-Huang stability criterion is also satisfied, confirming the robust mechanical stability. A large Seebeck voltage of more than 150 {\mu}V/K is estimated, an essential and typical requirement for improved heat-to-electricity conversion efficiency. This Seebeck voltage can be further increased by an order of magnitude with suitable doping. The PHONO3PY algorithm and Slack's model are used to compare the lattice thermal conductivity. The latter method gives more values than the former algorithm. Despite the commonly used constant relaxation time approximation to estimate the TE performance, we adopt the temperature-dependent relaxation time and found a clear drop in figure-of merit (zT) from those estimated without considering the lattice thermal conductivity and relaxation time both, still, the zT values are remarkably more than two, for the temperatures above 500 K, which is a striking numeral in the field of TE materials.

cond-mat.mtrl-sci↗