Partial substitution of certain cations for manganese is an attractive route to improve the electrochemical property of LiMn2O4. In this paper, we focus on the effect of chromium substitution. LiCryMn2-yO4 (y = 0.00, 0.03, 0.05, 0.08, 0.12, 0.16, 0.20) has been prepared and their structure and electrochemical characteristics have been investigated. Rietveld refinements of the XRD patterns indicated that with increasing Cr content, the occupation of Mn3+ (or Cr3+) in octahedral 16d sites increased and the crystal structure improved. At the same time, in the 32e (z, z, z) sites, which are occupied by oxygen, the value of z also increases and result in decreasing th& bond lengths of O-M (Mn, Cr) and Mn-Mn and increasing the bond length of O-Li. The optimal composition was LiCr3Mn2-yO4 0.05), whose initial discharge capacity was 121.6 mAh g(-1). (C) 2003 Elsevier B.V. All rights reserved.