Ultrasonic spray pyrolysis was used to form submicrometer particles of Li3Fe2(PO4)(3). The amorphous state and thermal properties of the precursor green powder were examined. The precursor powders were converted into crystalline Li3Fe2(PO4)(3) by heat treatment at 800-900 degreesC. The high-density (98%) ceramic samples were prepared by a hot pressing technique. The electrical conductivity of the ceramics was similar to 10(-8) and 2.5.10(-2) S/cm at 300 and 600 K, while the activation energies were about 0.74, 1.2 and 0.48 eV for alpha, beta and gamma -phases, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.