2O 4 via surface-modified by Li-rich Li 1.2Ni 0.2Mn 0.6O 2 for lithium-ion batteries]]>

摘要

AbstractIn order to improve the electrochemical performance of LiMn2O4at elevated temperatures, a series of Li1.2Ni0.2Mn0.6O2-modified LiMn2O4samples have been synthesized by a facile sol-gel method. The structure and morphology of pristine and modified LiMn2O4are investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The Li1.2Ni0.2Mn0.6O2coating layer is identified by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), which plays an important role in reducing the dissolution of manganese, thereby improving the cycle performance and rate capability of the material. The 2?wt% Li1.2Ni0.2Mn0.6O2-modified LiMn2O4sample exhibits a higher capacity retention of 95.88% than that of the pristine one (81.2%) after 200 cycles at 1C and 25?°C. Furthermore, a capacity retention of 89.74% is obtained for the 2?wt%-modified LiMn2O4sample after 200 cycles at 1C and 55?°C, compared to 66.34% for the pristine one. Surface modification with a Li-rich Li1.2Ni0.2Mn0.6O2material is a good way to improve the elevated temperature performance of LiMn2O4.Highlights?The well-distributed surface modification with Li1.2Ni0.2Mn0.6O2coating layer.?Li1.2Ni0.2Mn0.6O2layer suppressing the dissolution of LiMn2O4in electrolytes.?Li1.2Ni0.2Mn0.6O2-modified LiMn2O4exhibits excellent capacity retention at elevate temperatures?Li1.2Ni0.2Mn0.6O2-modified LiMn2O4exhibits superior electrochemical performance to LiMn2O4