Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology , Ulsan, 44919, Republic of Korea.
Nano Lett. 2017 Jun 14;17(6):3744-3751. doi: 10.1021/acs.nanolett.7b01076. Epub 2017 May 10.
Despite their good intrinsic rate capability, nanosized spinel cathode materials cannot fulfill the requirement of high electrode density and volumetric energy density. Standard carbon coating cannot be applied on spinel materials due to the formation of oxygen defects during the high-temperature annealing process. To overcome these problems, here we present a composite material consisting of agglomerated nanosized primary particles and well-dispersed acid-treated Super P carbon black powders, processed below 300 °C. In this structure, primary particles provide fast lithium ion diffusion in solid state due to nanosized diffusion distance. Furthermore, uniformly dispersed acid-treated Super P (ASP) in secondary particle facilitates lower charge transfer resistance and better percolation of electron. The ASPLMO material shows superior rate capability, delivering 101 mAh g at 300 C-rate at 24 °C, and 75 mAh g at 100 C-rate at -10 °C. Even after 5000 cycles, 86 mAh g can be achieved at 30 C-rate at 24 °C, demonstrating very competitive full-cell performance.
尽管纳米尖晶石阴极材料具有良好的固有倍率性能，但它们无法满足高电极密度和体积能量密度的要求。由于在高温退火过程中会形成氧缺陷，因此标准的碳涂层不能应用于尖晶石材料。为了克服这些问题，我们在这里提出了一种由团聚的纳米级初级颗粒和分散良好的经酸处理的 Super P 炭黑粉末组成的复合材料，其加工温度低于 300°C。在这种结构中，由于纳米级扩散距离，初级颗粒在固态中提供了快速的锂离子扩散。此外，在次级颗粒中均匀分散的经酸处理的 Super P（ASP）有助于降低电荷转移电阻并改善电子的渗流。ASPLMO 材料表现出优异的倍率性能，在 24°C 时以 300 C 倍率可提供 101 mAh g 的容量，在-10°C 时以 100 C 倍率可提供 75 mAh g 的容量。即使经过 5000 次循环，在 24°C 时以 30 C 倍率仍可达到 86 mAh g 的容量，展示了非常有竞争力的全电池性能。
