Influence of synthesis parameters on the electrical and structural properties of nanostructured BPO4–Li2O

Li-doped BPO4 is a promising ceramic Li+-ion conducting electrolyte for all-solid-state Li-ion batteries. The influence of the synthesis conditions on the structural and electrical properties of nanostructured Li-doped BPO4 was investigated. The particle size of the material can be changed by varying the synthesis parameters. In order to investigate the relation between the particle size and the Li+-ion conductivity a series of samples was synthesized for temperatures between 150 and 600°C for 1.3 to 10 h. Two different synthesis routes were used and the composition, phase(s), Li+-ion conductivity, particle size, and particle morphology have been determined. As a result, single-phase Li-doped BPO4 with a particle size of 30 nm was obtained at a synthesis temperature as low as 150°C and synthesis time of only 5 h. Furthermore, a smaller particle size results in a higher Li+-ion conductivity.