Structure and electrochemical properties of LiLa_xMn_(2-x)O_4 cathode material by the ultrasonic-assisted sol-gel method
【摘要】：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) spectroscopy,scanning electronic microscopy(SEM) ,galvanostatic charge-discharge test,and cyclic voltammetry(CV) . XRD results show that 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.