Synthesis, characterization, and cell performance of LiNiVO4 cathode materials prepared by a new solution precipitation method

LiNiVO4 was prepared by a new solution precipitation process using acetylac etonate as a reagent. The effects of pH value on the purity, grain size, li thium stoichiometry, and cycling behavior of LiNiVO4 were studied. Solution precipitation performed in an acidic medium of pH = 3 with heat-treatment at 450 degrees C for 12 h yielded pure and fine LiNiVO4 powders which showe d lithium stoichiometry of 0.971 and narrow grain-size of 0.34 mu m. Under neutral and basic conditions, the LiNiVO4 particles were contaminated with NiO and formed aggregates with a larger grain size in the 0.36-0.54 mu m ra nge. The resulting LiNiVO4 powders were characterized by TGA, XRD, ICP-AES, SEM, and AFM techniques. Moreover, the cycle behavior of LiNiVO4 products synthesized by a high temperature solid state method and this new solution precipitation method was compared and discussed. (C) 1999 Elsevier Science S.A. All rights reserved.