State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, WUT-Harvard Joint Nano Key Laboratory, Wuhan University of Technology , Wuhan 430070, China.
Nano Lett. 2015 Jan 14;15(1):738-44. doi: 10.1021/nl504427d. Epub 2014 Dec 12.
Transition metal oxides have attracted much interest for their high energy density in lithium batteries. However, the fast capacity fading and the low power density still limit their practical implementation. In order to overcome these challenges, one-dimensional yolk-shell nanorods have been successfully constructed using manganese oxide as an example through a facile two-step sol-gel coating method. Dopamine and tetraethoxysilane are used as precursors to obtain uniform polymer coating and silica layer followed by converting into carbon shell and hollow space, respectively. As anode material for lithium batteries, the manganese oxide/carbon yolk-shell nanorod electrode has a reversible capacity of 660 mAh/g for initial cycle at 100 mA/g and exhibits excellent cyclability with a capacity of 634 mAh/g after 900 cycles at a current density of 500 mA/g. An enhanced capacity is observed during the long-term cycling process, which may be attributed to the structural integrity, the stability of solid electrolyte interphase layer, and the electrochemical actuation of the yolk-shell nanorod structure. The results demonstrate that the manganese oxide is well utilized with the one-dimensional yolk-shell structure, which represents an efficient way to realize excellent performance for practical applications.
过渡金属氧化物因其在锂电池中的高能量密度而备受关注。然而，快速的容量衰减和低的功率密度仍然限制了它们的实际应用。为了克服这些挑战，采用锰氧化物作为实例，通过简便的两步溶胶-凝胶包覆法成功构建了一维蛋黄壳纳米棒。多巴胺和四乙氧基硅烷分别用作前体，以获得均匀的聚合物包覆层和二氧化硅层，然后分别转化为碳壳和空心空间。作为锂电池的阳极材料，锰氧化物/碳蛋黄壳纳米棒电极在 100 mA/g 的电流密度下初始循环时具有 660 mAh/g 的可逆容量，在 500 mA/g 的电流密度下经过 900 次循环后具有 634 mAh/g 的优异循环性能。在长期循环过程中观察到了增强的容量，这可能归因于蛋黄壳纳米棒结构的结构完整性、固体电解质界面层的稳定性和电化学驱动。研究结果表明，锰氧化物与一维蛋黄壳结构得到了很好的利用，这为实现实际应用中的优异性能提供了一种有效的方法。
