Enhanced cycle stability at high rate and excellent high rate capability of La0.7Sr0.3Mn0.7Co0.3O3-coated LiMn2O4

La0.7Sr0.3Mn0.7Co0.3O3-coated spinel LiMn2O4 with excellent cycle stability and high rate capability is successfully prepared by a sol-gel method. The 3 wt.% La0.7Sr0.3Mn0.7Co0.3O3-coated LiMn2O4 shows the optimum electrochemical performance. It can deliver 101 mAh g−1 at 10 C even after 100 cycles with a capacity retention of 93.5%. In contrast, the bare LiMn2O4 delivers 83.6 mAh g−1 at the same condition, only 84.5% capacity left. The rate capability of 3 wt.% La0.7Sr0.3Mn0.7Co0.3O3-coated LiMn2O4 is also obviously enhanced, especially at high rates (10 C, 20 C and 30 C). It can deliver 74.3 mAh g−1 at 30 C which is much higher than that of the bare sample (47.2 mAh g−1). The bare and coated LiMn2O4 samples are studied with various techniques. Both powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements demonstrate the existence of the La0.7Sr0.3Mn0.7Co0.3O3, and it has no influence on the crystal structure of the pristine LiMn2O4. Transmission electron microscopy (TEM) shows that La0.7Sr0.3Mn0.7Co0.3O3 coating layer with good crystallinity can cover the surface of LiMn2O4 to form a core-shell structure. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) demonstrate that the coating layer can improve the kinetics of electrodes.