Fast fluoride ion conducting materials in solid state ionics: An overview

•An overview of various fluoride materials exhibiting fluoride ion conductivity•Different synthesis methods for the preparation of fluoride materials•Discussion on the transport characteristics of the materials crystallizing in different forms•Application aspects of fluoride materials in different electrochemical devices

This review article presents a brief overview of synthesis and application aspects of fast fluoride ion conducting materials in the field of Solid State Ionics. Possible synthesis methodologies known in the literature for the preparation of various fluoride materials have been outlined. Further, their transport characteristics with respect to their crystal structure have been discussed. Various approaches influencing their ionic conductivity value in the light of synthesis methodology, composition, dopant concentration, crystallite size, microstructure etc. have been reviewed. At the end, possible technological applications of fast fluoride ion conducting materials in different solid state ionic devices have been presented.