Structural and electrochemical properties of Cr-substituted lithium manganese oxide thin films

LiCrxMn2−xO4 (x ≤ 0.3) thin films were fabricated on Pt/Ti/SiO2/Si substrates by using a sol–gel technique and post-annealing in air for 6 h at 700 °C.The LiCrxMn2-xO4 specimens were found to have the spinel structure of pristine LiMn2O4 with no detectable secondary phase.The Cr ions were found to be trivalent and to occupy the octahedral sites of the spinel lattice.A new phonon mode (δ) near 570 cm−1 observed in the Raman spectra of the Cr-substituted specimens confirms the octahedral Cr3+ occupation in the spinel lattice.The LiCrxMn2-xO4 cathodes with small Cr3+ compositions (x < 0.1) exhibited better capacity retention than the pristine LiMn2O4 cathode.