There have been literature reports on Co1-zZrz(OH)(2) and LiCo1-zZrzO2 in the study of layered double hydroxides and positive electrodes for Li-ion batteries, respectively. However, the different oxidation states of Co (2+ or 3+) and Zr (4+) suggest that the amount of substitution, z, will be limited. In this paper, the precipitate, hoped to be Co1-zZrz(OH)(2), formed by the addition of an aqueous solution of Co(NO3)(2) and ZrO(NO3)(2) to LiOH solution has been thoroughly studied as a function of the Zr/(Zr + Co) ratio, z, for 0 <= z <= 1. X-ray diffraction and thermogravimetric analysis results show that Zr is not incorporated into the brucite-like layers and do not substitute for a part of the divalent cations Co2+. Instead, the added Zr forms ZrO(OH)(2) or Zr(OH)(4) impurities. Attempts to prepare LiCo1-zZrzO2 samples from the hydroxide precursors over the range 0 <= z <= 0.1 failed. The products were found to be LiCoO2 and ZrO2 or Li2ZrO3 impurities, even for z = 0.01. This suggests that LiCo1-zZrzO2 cannot be prepared even for additions of Zr as low as 1%. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3523285] All rights reserved.