State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
Nanoscale. 2013 Aug 21;5(16):7564-71. doi: 10.1039/c3nr02385k. Epub 2013 Jul 9.
Superposed cobalt(II)-cobalt(III) layered double hydroxide (Co(II)-Co(III)-LDH) nanoplates were synthesized by an oil droplet template method, in which the main steps are as follows: LDH nanosheets were first assembled on an oil droplet template to form a multishell sphere, and then the oil droplet was easily removed under centrifugal force due to its very different density from that of the assembled LDH shell. This resulted in the multishell spheres being split open to create superposed LDH nanoplates. The resulting material has a three-stage architecture, namely, the primary building blocks of nanosheets, the secondary architecture of shells derived from the nanosheets, and the long-range architecture of superposed nanoplates assembled from the vertically stacked shells. Most importantly, the as-fabricated LDH-based hierarchical structure can be readily converted to a Co3O4/C composite via calcination, without obvious structural alteration, where the residual surfactant is the source of the carbon. When used as an anode material for Li-ion batteries, the Co3O4/C electrode exhibits an excellent electrochemical performance, which is attributed to the unique hierarchically porous structure.
超叠钴(II)-钴(III)层状双氢氧化物（Co(II)-Co(III)-LDH）纳米片通过油滴模板法合成，其主要步骤如下：首先在油滴模板上组装 LDH 纳米片，形成多壳球，然后由于油滴与组装 LDH 壳的密度差异很大，很容易通过离心力去除油滴，从而导致多壳球被分裂形成超叠 LDH 纳米片。所得材料具有三级结构，即纳米片的初级结构单元、纳米片衍生的壳的次级结构和由垂直堆叠的壳组装而成的超叠纳米片的长程结构。最重要的是，所制备的基于 LDH 的分级结构可通过煅烧轻易转化为 Co3O4/C 复合材料，而没有明显的结构改变，其中残留的表面活性剂是碳的来源。当用作锂离子电池的阳极材料时，Co3O4/C 电极表现出优异的电化学性能，这归因于独特的分级多孔结构。
