MATTHEW S. JAMES*, PETER R. SLATER
*Corresponding author
University of Birmingham, United Kingdom

Abstract

Incorporation of fluorine into Perovskite and related transition metal oxide systems has attracted considerable interest after the discovery of high temperature superconductivity in Sr₂CuO₂F_2+δ. 

One of the challenges associated with making such phases is their instability at higher temperatures (above 500 °C) due to high thermodynamic stability of the simple fluoride starting materials. Thus, the low temperature fluorination (below 450 °C) of precursor systems has been utilised to synthesise such systems, with growing interest in polymer reagents such as. PVDF, PTFE as the fluorine source. In this review, we discuss recent work on the use of such polymer reagents to prepare novel perovskite and related materials, and highlight the resulting magnetic properties of these materials as well as the potential of such systems for use in Fluoride ion batteries.

INTRODUCTION 

Perovskite and related materials have attracted considerable interest due to the fact that they display a wide range of technologically important properties. Much of this work has focused on simple oxide systems; however the development of new synthesis routes towards perovskite oxide fluoride materials has opened up new avenues for materials design so as to optimise physical properties such as superconductivity, electronic conductivity, ionic conductivity and magnetism (1).

Perovskites have the ideal general formula ABX₃ (Where A is a large cation, e.g. Ca²⁺, Sr²⁺, Ba²⁺, La³⁺ or other rare earth metals, B is a smaller cation, e.g., transition metal, Al³⁺, Ga³⁺ or In³⁺ and X is a anion, e.g. O^2- or halide), and are heavily researched for a wide range of potential applications.

Related materials are the Ruddlesden Popper systems (Figure 1) with general formula: A_n+1B_nX_3n+1 (n=1 also commonly called the K₂NiF _... ...