• Heitjans, Paul

Abstract

For many applications such as advanced energy storage systems, chemical sensors or electrochromic devices fast ionic conduction plays an important role. In many cases, see e.g., Refs. [1-3], nanocrystalline ceramics with crystallite diameters smaller than 50 nm show an enhanced ion conductivity compared to their coarse-grained counterparts, i.e., single crystals or materials with µm-sized particles. This observation can be explained by their large fraction of structurally disordered interfacial regions providing fast migration pathways for the ions [2,3]. Mechanical treatment of µm-sized particles in a high-energy ball mill represents a simple technique to obtain large quantities of a nanocrystalline material. In addition to that it is also possible to synthesize ceramics directly by ball milling [3]. In many cases this leads to metastable, non-equilibrium compounds which cannot be prepared following conventional synthesis methods [4,5]. In the present paper, BaLiF3, the only known inverted perovskite of the AMF3 compounds [6], was prepared by high-energy ball milling using a Fritsch P7 planetary mill (premium line). An equimolar mixture of LiF and BaF2 with an overall mass of 2 g was treated in a 45 mL zirconia vial with 140 balls of the same material for 3 h at a rotational speed of 600 rpm. As verified by X-ray diffraction highly pure BaLiF3 is obtained which shows an average crystallite size d of about 30 nm. d was estimated

Topics

• perovskite
• impedance spectroscopy
• compound
• single crystal
• x-ray diffraction
• milling
• ball milling
• ball milling
• interfacial