On the aggregation process of ceramic LiSn2P3O12 particles embedded in Teflon matrix

Abstract

Composites having ceramic LiSn2P3O12 particles, that are Li+ ion conductor, and Teflon, that is an insulating polymer and works as binder, have been prepared in a wide compositional range (from 8 to 74% by volume of LiSn2P3O12). Their microstructure, as followed by Scanning Electron Microscopy, has been analyzed to understand the aggregation process of the ceramic particles. For low LiSn2P3O12 contents (below 30% by volume) some particles lay isolated and some aggregated in clusters (isolated clusters) both being surrounded by Teflon. For higher LiSn2P3O12 contents the isolated clusters grow and transform into clusters that are developed along the composite bulk (extended clusters); the latter clusters accounts for the ionic conductivity, which is discussed in terms of a percolation model. The shape and size of both types of clusters are analyzed as the LiSn2P3O12 content increases. The aggregation process here described could work in other composites made from mixing and compacting particles of a ceramic and a polymer.