Li+-ion conductivity of BPO4-Li2O; the relation between crystal structure and ionic conductivity

By combining structural data with electrical data of nano-structured Li-dop ed BPO4 the relation between crystal structure and Li+-ion conductivity is derived. A maximum ionic conductivity is found by changing the Li-doping le vel and is related to the structural changes. Previously, two possible defe ct models for Li-doped BPO4 were derived from structural data, however the maximum conductivity could not be explained by these defect models. From pr eliminary Rietveld refined X-ray diffraction data this maximum can be attri buted to a change in the a- and c-axes and the related tunnel size for Liions. Another possible explanation for the conductivity maximum is the role of the particle size which depends on the Li-doping level. (C) 1999 Elsevi er Science B.V. All rights reserved.