Impacts of Cr Substitution on Ion Distributions and Electrochemical Performance of LiNi0.5-xCr2xMn1.5-xO4 Cathode Materials

A spinel-structured LiNi0.5-xCr2xMn1.5-xO4(x=0, 0.05) were prepared via co-precipitation routes. The experiment results from XRD, SEM and electrochemical analyses show that the substitutions of Ni and Cr for Mn in LiMn2O4can not prevent Mn2+from being oxidized into Mn3+ in solution process, however,Mn2+ oxidation does not change their final crystal structures of spinel phase, but do influence the Li/Ni2+ cation mixing and Mn3+occurrence in lattice. After substitution the first charge and discharge capacities decrease but its cycleability is improved significantly, especially for the Ni and Cr co-substitution