Structural and Electrochemical Properties of Li(LaAl)xMn2−xO4 Based Composite Cathodes
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Spinel oxides lanthanum (La) and aluminium (Al) doped Li(LaAl)xMn2−xO4 (x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) compounds were prepared by a sol–gel method. Lanthanum and aluminium showed an influence on the structural, morphological and electrochemical properties. An x-ray diffraction study revealed that all the samples are in the cubic spinel phase. The grain size from the Debye–Scherrer and Williamson–Hall methods is comparable at lower doping concentration. Field emission scanning electron microscopy shows that the particle size of the samples increased with increasing dopant concentration, and the particle sizes were found to be between 50 nm and 200 nm. Cyclic voltammetry studies show two sets of well separated redox peaks due to the formation of Li+ extraction/insertion into the spinel framework at a scan rate of 0.5 mV/s in the potential range of 0.2–1.2 V. Electrochemical impedance spectroscopy studies show that (LaAl) 0.01 doping improved charge transfer resistance. Li(LaAl)0.01Mn1.98O4 showed better discharge capacity (68.2 mAh/g) over other doped derivatives and pristine LiMn2O4 in saturated Li2SO4 aqueous electrolyte.
KeywordsSol–gel method x-ray diffraction FE-SEM cyclic voltammetry charge–discharge characteristics
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One of the authors (AVR) thanks the management of Koneru Lakshmaiah Education Foundation for their encouragement and support in executing the Project. Authors AVR and BRK acknowledge the financial support from Department of Science and Technology-SERB vide Grant No. SB/FTP/ETA-0176/2014 under the Young Scientist scheme.
- 9.T. Jian-Kun, W. Fu-Cheng, V.S. Battaglia, and Z. Hai-Lang, Int. J. Electrochem. Sci. 9, 931 (2014).Google Scholar