DEFECT STRUCTURE OF Li-DOPED BPO4: A NANOSTRUCTURED CERAMIC ELECTROLYE FOR Li-ION BATTERIES

摘要

In this paper the defect chemistry of Li-doped BPO4 (BPO4-xLi2O, 0 less than or equal to x less than or equal to 0.1) is studied. This nanostructured ceramic electrolyte is used in all-solid-state Li-ion batteries. By changing the Li-doping level the influence on the crystal structure is studied and related to t he properties of the material. XRD, FT-IR, 31P, 11B, and 7Li MAS solid state NMR, neutron diffraction, and inductively coupled plasma optical-emission spectroscopy measurements are used in order to study the structure. The electrical properties are studied with AC-impedance spectroscopy (AC-IS). The experimental data show that the defect structure of Li-doped BPO4 can be described with two defect models, Li double prime B+2Li supp. i and V triple prime B+3Li supp. i, suggesting that the ionic conductivity takes place via interstitial Li ions. 10 refs.