以喷雾热解法制备出了能量密度高,电化学性能优异的LiCr0.2Ni0.4Mn1.4O4正极材料。采用热重分析、X射线衍射、扫描电镜、循环伏安、交流阻抗等手段进行了测试与表征,并且在现有市售高电压电解液耐受条件下,对不同截止电压(3.6~5.0 V,3.6~5.2 V)的电化学特性做了详细的研究。结果表明：此法所得材料峰形尖锐结晶良好,且无杂质相生成,粒度分布较为均一,为微米-亚微米级颗粒。在5.2 V充电截止电压下,0.5C倍率下首次放电容量高达142.9 mAh/g,且0.5C及1C下二者的能量密度均在600 Wh/kg以上。当截止电压为5.2 V,放电深度增大,低倍率比容量提高,但大倍率容量,循环稳定性及放电电压工作平台下降均较为明显。
Cathode material of LiCr0.2Ni0.4Mn1.4O4 with high energy density and superior electrochemical properties was fabricated by means of spray pyrolysis. The material was characterizedvia thermogravimetric analysis (TG), X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical imped-ance spectroscopy (EIS) in detail, and within the tolerance of current available electrolyte the discrepancy of different cut-off voltages (3.6-5.0 V, 3.6-5.2 V) was investigated. The results demonstrate that the obtained material is crystal-lized well without any formation of impurities, and a relative uniform particle size distribution is within micron and sub-micron. In the voltage window of 3.6-5.2 V, the initial discharge capacity can reach as high as 142.9 mAh/g at 0.5C, and its values of energy densitiy at 0.5C and 1C surpass 600 Wh/kg. If the cut-off voltage is set at 5.2 V, the de-gree of discharge and low-rate capacity are increased, while its high-rate capacity, cycling stability and working volt-age platform are deteriorated seriously.
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