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 La^3＋ can partially reptace Mn^3＋ in the spinel and the doped materials with La^3＋ have a larger lattice constant compared with pristine LiMn2O4. FT-IR indicates that the absorption peak of Mn^3＋-O and Mn^4＋- 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 doping La^3＋ is beneficial to the reversible extraction and intercalation of Li^＋ ions.
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 La^3＋ can partially reptace Mn^3＋ in the spinel and the doped materials with La^3＋ have a larger lattice constant compared with pristine LiMn2O4. FT-IR indicates that the absorption peak of Mn^3＋-O and Mn^4＋- 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 doping La^3＋ is beneficial to the reversible extraction and intercalation of Li^＋ ions.
