Abstract—

Using a simple and technological approach, we have fabricated composites based on a lithium iron phosphate (LFP) with the olivine structure and a carbon coating containing 5–10% carbon nanotubes (CNTs) or nanoflakes. Materials prepared with the use of mechanochemical activation have a slightly smaller particle size. At the same time, their electrical conductivity is higher by several orders of magnitude, reaching 8.7 × 10^–2 S/cm for the best samples. Moreover, the synthesized materials demonstrate a considerable increase in their reversible capacity, especially at high battery charge/discharge rates. The composites containing carbon nanotubes show the best performance. In particular, the discharge capacity of the LFP/C/10CNT-500 composite is 120, 97, 78, and 57 mAh/g at current densities of 200, 800, 1600, and 3200 mA/g, respectively, whereas the discharge capacity of the pristine LFP/C is 70, 63, 43, and 30 mAh/g. This effect is due to a decrease in particle size and the formation of a network of high-conductive contacts between particles of the cathode material. No clear correlation has been found between the electrochemical capacity of the composites and their specific surface area or electrical conductivity.

中文翻译：

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用于高功率锂离子电池阴极的 LiFePO4/碳纳米材料复合材料

摘要-

使用简单的技术方法，我们制造了基于具有橄榄石结构的磷酸铁锂 (LFP) 和包含 5-10% 碳纳米管 (CNT) 或纳米薄片的碳涂层的复合材料。使用机械化学活化制备的材料具有稍小的粒度。同时，它们的电导率高了几个数量级，达到了 8.7 × 10 ^–2S/cm 为最佳样品。此外，合成材料的可逆容量显着增加，尤其是在高电池充电/放电速率下。含有碳纳米管的复合材料表现出最好的性能。特别是，LFP/C/10CNT-500 复合材料在 200、800、1600 和 3200 mA/g 的电流密度下的放电容量分别为 120、97、78 和 57 mAh/g，而放电容量分别为原始 LFP/C 的 70、63、43 和 30 mAh/g。这种效应是由于颗粒尺寸的减小和阴极材料颗粒之间高导电接触网络的形成。尚未发现复合材料的电化学容量与其比表面积或电导率之间存在明显的相关性。