The structure of superionic glasses in ternary systems x(0.4Li2S-0.6P2S5)-(1 - x)LiI and x(0.5Li2S-0.5P2S5)-(1 - x)LiI (x = 0.9, 0.75) has been studied by molecular dynamics (MD) simulations. The configurations obtained by MD were analyzed by graph theory. Phosphorus is surrounded by sulfur and iodine atoms. Li is surrounded by sulfurs alone and LiI clusters are not present as speculated by earlier spectroscopic reports. The equilibrium configuration is made up of (Li, S) and (P, S, I) rich regions which creates wide channels for Li+ movement. Reported variations of glass transition temperature (Tg) and ionic conductivity (σ) with LiI addition are explained based on the simulation results. © 2006 Elsevier B.V. All rights reserved.

Maha Seshasayee

Computer simulation

glass transition

Graph theory

Iodine

molecular dynamics

Phosphorus

Spectroscopic analysis

Chalcogenides

fast ion conduction

TERNARY GLASSES

Lithium compounds

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Non-Crystalline Solids

The structures of xLi2O-(1 - x)PzO5 glasses with x = 0.10, 0.20 and 0.30 have been examined using X-ray radial distribution functions. The composition range x = 0.10-0.75 also has been studied by molecular dynamics simulations. MD configurations were analyzed using graph theory techniques. The experimental glass transition temperature reaches a minimum at 20mol% of Li2O and the simulated glass has a minimum Tg at 23mol% of Li2O. This minimum in Tg has been explained by studying the changes in the environment of Li, P and O with Li2O composition and connectivities among the PO4 groups mediated by lithium existing in the network. X-ray RDF studies agree with the MD simulation results. Dynamic parameters of interest to structure-transport studies, namely mean square displacement and velocity autocorrelation function obtained from the MD simulations, identify Li+ as the mobile ion contributing to ionic conductivity. © 2004 Elsevier B.V. All rights reserved.

Structural study of lithium phosphate glasses by X-ray RDF and computer simulations

Molecular dynamics simulation of binary glass 52Li2O-48P 2O5 and ternary glasses 45Li2O-42P 2O5-13LiCl and 39Li2O-36P2O 5-25LiCl was undertaken to study the effects of the addition of LiCl to the binary phosphate glass. The results show that addition of LiCl in the glass creates more non-bridging oxygens and reduces P-O-P chain lengths and branches in these chains, leading to a weakening of the glass matrix and consequent lowering of Tg. Interchain linkages mediated by Li in the binary structure diminish, and consequently better channels are created for Li+ movement, enhancing the ionic conductivity σ. Structure parameters also indicate the absence of LiCl clusters in the glass matrix. © 2004 Published by Elsevier Ltd.

Solid State Communications

Molecular dynamics simulation of ternary glasses Li2O-P 2O5-LiCl

Solid State Ionics

Aggregation of the doping salt in B2S3–Li2S–LiI glasses, effect on the dynamical properties

11B NMR studies of the local environment of boron in B2S3Li2SLiI glasses

Journal of Solid State Chemistry

Glass-forming region and structure in SiS2Li2SLiX (X = Br, I)

Molecular dynamics simulation of ternary glasses Li2S-P2S5-LiI

Journal	Journal of Non-Crystalline Solids
ISSN	00223093
Open Access	No