Structure and electrochemical behavior of LiCryMn2−yO4 compositions

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 the bond lengths of O–M (Mn, Cr) and Mn–Mn and increasing the bond length of O–Li. The optimal composition was LiCryMn2−yO4 (y=0.05), whose initial discharge capacity was 121.6 mAh g−1.