Synthesis and physicochemical properties of LiLa 0.01Mn 1.99O 3.99F 0.01 cathode materials for lithium ion batteries

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Spinel lithium manganese oxide cathode materials were synthesized using the ultrasonic-assisted sol-gel method. The synthesized samples were investigated by differential thermal analysis (DTA) and thermogravimetry (TG), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), and the charge-discharge test. TG-DTA shows that significant mass loss occurs in two temperature regions during the synthesis of LiLa 0.01Mn 1.99O 3.99F 0.01. XRD data indicate that all samples exhibit the same pure spinel phase, and LiLa 0.01Mn 1.99O 3.99F 0.01 and LiLa 0.01Mn 1.99O 4 samples have a better crystallinity than LiMn 2O 4. SEM images indicate that LiLa 0.01Mn 1.99O 3.99F 0.01 has a slightly smaller particle size and a more regular morphology structure with narrow size distribution. The charge-discharge test reveals that the initial capacities of LiMn 2O 4, LiLa 0.01Mn 1.99O 4, and LiLa 0.01Mn 1.99O 3.99F 0.01 are 130, 123, and 126 mAh·g 1, respectively, and the capacity retention rates of the initial value, after 50 cycles, are 84.8%, 92.3%, and 92.1%, respectively. The electrode coulomb efficiency and CV reveal that the electrode synthesized by the ultrasonic-assisted sol-gel (UASG) method has a better reversibility than the electrode synthesized by the sol-gel method.