Novel nanomaterials based on electronic and mixed conductive glasses
Résumé
Novel nanomaterials based on lithium-vanadate-phosphate (LVP) and lithium-iron-phosphate (LFP) glasses were prepared and their electrical properties were investigated by impedance spectroscopy. It was found out that the electronic conductivity of the original glasses of both systems can be considerably enhanced by appropriate annealing at temperatures close to beginning of crystallization temperatures determined by DSC/DTA methods. Increase in conductivity arises from the modification of the microstructure. it was shown by XRD and SEM studies that by appropriate heat-treatment glasses of both systems can be turned into nanomaterials consisting of crystallites smaller than 100 nm embedded in the glassy matrix. It was postulated that the major role in the conductivity enhancement of these nanomaterials is played by the developed interfacial regions between nanocrystalline and glassy phases, in which the concentration of v(4+)-v(5+) or Fe(2+)-Fe(3+), pairs responsible for electron hopping in those systems, is higher than inside the glassy matrix and the formed nanocrystallites. (C) 2008 Elsevier B.V. All rights reserved.