Lithium ion conducting ceramics Li-1 (+) Zr-2x(2) (-) Sr-x(x)(PO4)(3) with x = 0-0.2 were synthesized via a sot-gel method using citric acid. The effects of Se2+ substitution on the structure, microstructure, and conductivity of LiZr2(PO4)(3) ceramics were studied. Rietveld refinement of powder XRD patterns showed that 5% of Sr2+ substitution for Zr4+ in LiZr2(PO4)(3) stabilizes the rhombohedral (space group R (3) over barc) phase at room temperature. Sr2+ doped LiZr2(PO4)(3) samples exhibited significantly improved ionic conductivity with Li1.2Zr1.9Sr0.1 (PO4)(3) showing highest conductivity of 0.34 x 10(-4) Omega(-1) cm(-1) at room temperature. Activation energy was found to decrease from 0.56 eV for LiZr2(PO4)(3) to 0.40 eV for Li1.4Zr1.8Sr0.2(PO4)(3). Li+ transference number determined by DC polarization for Li1.2Zr1.9Sr0.1(PO4)(3) was close to 1 confirming the ionic nature of conductivity. (C) 2016 Elsevier B.V. All rights reserved.