The defect chemistry of BPO4-xLi2O, where x ranged from 0 to 0.1, was studied. Fourier-transform infra-red spectroscopy, X-ray diffraction, magic-angle-spinning solid-state nuclear magnetic resonance, neutron diffraction, and inductively coupled plasma optical-emission spectroscopy were used to study the structure as a function of Li-doping level. The electrical properties were studied using alternating-current impedance spectroscopy. The results showed that the defect structure of Li-doped BPO4 could be described by 2 defect models, LiB"+2Lii• and VB'''+3Lii•; thus suggesting that the ionic conductivity occurred via interstitial Li ions.

Defect Structure of Li-Doped BPO4: a Nanostructured Ceramic Electrolyte. M.J.G.Jak, E.M.Kelder, J.Schoonman: Journal of Solid State Chemistry, 1999, 142[1], 74-9