AB-INITIO STUDY OF SUPERIONIC CONDUCTORS
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Date
2023-05-17
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DEPARTMENT OF PHYSICS KINNAIRD COLLEGE FOR WOMEN UNIVERSITY LAHORE,
Abstract
The use of halide materials as solid electrolytes has recently attained gigantic
research interest due to their ability to operate at high temperature. Under over
present knowledge novel halide electrolytes, such as LiYCl4, LiSmCl4, and LiAlCl4,
exhibit high Li-ionic conductivities, approaching 10-3 S/cm, with low activation
energies. A considerable experimental as well as theoretical efforts have been made
in the identification of optimal combination of Li-M-X, (M: metal, X: halide) that
are suitable at high temperature. Whereas, being a novel promising electrolyte
material, LiAlCl4, there are not too many literatures available for the electronic,
structural characteristics analysis of LiAlCl4. However, these characteristics
decides the suitable battery material such as the materials with wide bandgap of ~
6 eV are highly desirable. In this work, we employ Density Functional Theory
(DFT) simulations to conduct a study of Li-M-X with M= Al and X =Cl. Electronic,
structural properties and phase stability of LiAlCl4 is found. The values of the
bandgap 5.63 eV and 5.2 eV are calculated by the exchange correlation functionals,
Generalized Gradient Approximation (GGA) with Perdew-Burke-Ernzerhof (PBE)
and the Local Density Approximation (LDA) for LiAlCl4, respectively. Results
indicate that the GGA-PBE calculation gives a more desirable value closer to the
experimental band gap. These results agree with the true nature of GGA-PBE
method. On the other hand, experimental synthesis of electrolytes is time consuming and requires a lengthy process to achieve a perfect solid electrolyte.
Computational modeling minimizes cost, time and complements experiments by
providing unique theoretical insights to predict the state-of-the-art solid-state
electrolytes, which have been rarely reported. Our calculations determined that
LiAlCl4 shows promising potential as a battery electrolyte with a band gap of 5.63
eV, indicating the suitability of LiAlCl4 as a superionic conductor