Structure and electrochemical properties of LiLaxMn2-xO4 cathode material by the ultrasonic-assisted sol-gel method

Powders of spinel LiLaxMn2_xO4 were successfully synthesized by the ultrasonic-assisted sol-gel (UASG) method.The structure and properties of LiLaxMn2_xO4 were examined by X-ray diffraction (XRD),Fourier transform infrared (FT-IR) spectros-copy,scanning electronic microscopy (SEM),galvanostatic charge-discharge test,and cyclic voltammetry (CV).XRD results showthat the La3+ can partially replace Mn3+ in the spinel and the doped materials with La3+ have a larger lattice constant compared with pristine LiMn2O4.FT-IR indicates that the absorption peak of Mn3+-O and Mn4+-O bonds has a red and blue shift with the increase of doping lanthanum in LiLaxMn2_xO4,respectively.The charge-discharge test exhibits that the initial discharge capacity of LiLaxMn2_xO4 drops off,and the capacity retention increases gradually at C/5 discharge rate with the increase of doping lanthanum,and LiLa0.01Mn1.99O4 has a higher discharge capacity and a better cycling performance at 1C discharge rate.CV reveals that the dop-ing La3+ is beneficial to the reversible extraction and intercalation of Li+ ions.