Study of dielectric properties of (mgcuniznco)o and its lithium analogues pellets for its potential application as super-capacitor/battery electrolyte

Abstract

Entropic contributions to the stability of solids are very well understood and the mixing entropy has been used for forming various solids, for instance such as rocksalts. A particular development was related to high entropy alloys in which the configurational disorder is responsible for forming simple solid solutions and which are thoroughly studied for various applications especially due to their mechanical properties, electrical properties, hydrogen storage, magnetic properties. Many unexplored compositions and properties still remain for this class of materials due to their large phase space. In this thesis, it was shown that to prepare five equimolar binary oxides yield, after heating at high temperature and quenching, an unexpected rock salt structure compound with distribution of the cations in a face centered cubic lattice. Following this seminal study, here that these high entropy oxides can be substituted by aliovalent(Li - 5%,7.5%,10%) elements with a charge compensation mechanism. This possibility largely increases the potential development of new materials by widening their phase space. Here the aliovalent substitution of 7.5% lithium doped HEOx composition exhibits colossal dielectric constants of 1 x 105 order at 423k around 70Hz, which could make it very promising for applications as large-k dielectric materials.