Ion-conducting ceramics which were based upon the NASICON structure were prepared by substituting Nb or V for P. The processing method was shown to be the key factor which determined the bulk and grain-boundary conductivities that were observed, as well as the conductivity trends which were observed as a function of substitution.

Characterisation and Impedance Spectroscopy of Substituted (Li,Al,Ti)[(PO4),(ZO4)]3 Ceramics. A.S.Best, P.J.Newman, D.R.MacFarlane, K.M.Nairn, S.Wong, M.Forsyth: Solid State Ionics, 1999, 126[1-2], 191-6