Investigation of structural, vibrational spectroscopic and properties study of LiMn2O4 and LiMn1.9Cu0.05Fe0.05O4 cathode materials

• Main Authors: Paulos Taddesse, Haftom Gebrekiros, Gishu Semu, Mulugetta Duressa, Yadeta C. Chemeda, N. Murali, K. Vijaya Babu
• Format: Article
• Language: English
• Published: Elsevier 2021-12-01
• Series: Results in Materials
• Subjects: Cathode material; Solid state synthesis; Structure; Thermal property; Electrochemical property
• Online Access: http://www.sciencedirect.com/science/article/pii/S2590048X21000571

LiMn2O4 and LiMn1.9Cu0.05Fe0.05O4 cathodes were prepared by the solid-state reaction method. TGA-DTA analysis confirmed that Cu and Fe insertion into LiMn2O4 decreased the reaction temperature between LiOH.H2O and MnO2 precursors and increased the stability of the LiMn1.9Cu0.05Fe0.05O4 compound in a wider temperature range from 625 to 851 °C. XRD, FT-IR, and Raman spectroscopy study revealed the single-phase spinel cubic crystal structure (Fd-3m space group) of both cathodes. The average crystallite sizes were found to be 68 nm for LiMn2O4 and 72 nm for LiMn1.9Cu0.05Fe0.05O4. The concentrations of Li, Mn, Cu and Fe in the samples were estimated using ICP-OES. The microstructural behavior and elemental composition of both samples were detected by FE-SEM and EDS, respectively. The electrical conductivity of both cathodes was found to increase with increasing temperature. Cyclic voltammetry study confirmed that the Cu and Fe co-substitution improved the reversibility behavior of LiMn2O4. LiMn1.9Cu0.05Fe0.05O4 exhibited an improved cyclic performance of 97.9% after 30 cycles between 3.0 and 4.5 V, as compared to the LiMn2O4 cathode.