Department of Chemical Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea.
Nanoscale. 2013 Sep 7;5(17):7867-71. doi: 10.1039/c3nr01675g.
A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000(th) high discharge capacity of 108 mA h g(-1) at 10 C. The discharge capacities are as high as 103, 95, and 91 mA h g(-1) at extremely high discharge rates of 100, 200, and 300 C and the corresponding specific energy densities are 420, 370, and 328 W h kg(-1). The capacity retention at a constant discharge rate of 200 C is 90% after 500 cycles.
首次介绍了一种简便、连续的蛋黄壳结构锂金属氧化物粉末的制备方法，无需使用模板，可作为锂离子电池的阴极材料。以蔗糖为原料，通过喷雾热解直接制备单壳和双壳 LiNi0.5Mn1.5O4 蛋黄壳粉末，停留时间短至 4 s。在 700°C 的热壁反应器中，微尺度液滴内形成的碳混合氧化物复合中间相快速燃烧和收缩，产生蛋黄壳粉末。即使在 750°C 的高温后处理温度下，喷雾热解直接制备的前驱体粉末的蛋黄壳结构也能很好地保持。蛋黄壳结构的 LiNi0.5Mn1.5O4 粉末在 10 C 时具有 1000 次循环的 108 mA h g(-1)的高放电容量。在极高的放电速率 100、200 和 300 C 下，放电容量高达 103、95 和 91 mA h g(-1)，相应的比能量密度为 420、370 和 328 W h kg(-1)。在 200 C 的恒定放电速率下，循环 500 次后的容量保持率为 90%。
