最新色国产精品精品视频,中文字幕日韩一区二区不卡,亚洲有码转帖,夜夜躁日日躁狠狠久久av,中国凸偷窥xxxx自由视频

Al2O3-coated LiNi0.03Co0.05Mn1.92O4 cathode materials were prepared by combustion method with aluminum nitrate nonahydrate as raw material. The structure and morphology of the materials were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM), and the electrochemical performance were characterized by galvanostatic charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that Al2O3 coating did not change the spinel structure of LiNi0.03Co0.05Mn1.92O4, and the coating thickness was about 10.6 nm. The LiNi0.03Co0.05Mn1.92O4@Al2O3 material exhibited excellent electrochemical performance. The initial discharge capacity of the Al2O3 coated materials were 119.9mAh g-1 at 1C rate and 106.3 mAh?g-1 at 10 C rate, the capacity retention were 88.4 % and 78.2% after charge/discharge cycles for 500 times. While the initial discharge capacity of uncoated LiNi0.03Co0.05Mn1.92O4 were 121.2 mAh?g-1 and 104 mAh?g-1 at different rates, the retention rate were 84.1% and 67.6% after 500 cycles, respectively. Besides that, the LiNi0.03Co0.05Mn1.92O4@Al2O3 had a lower activation energy of 32.92 kJ?mol-1, while 36.24 kJ?mol-1 for the uncoated. The energy barrier needed for lithium ion diffusion was effectively reduced and the electrochemical performance of the cathode material was improved by coating.