Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, China.
Department of Macromolecular Science and Engineering, School of Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States.
ACS Appl Mater Interfaces. 2016 Jul 13;8(27):17402-8. doi: 10.1021/acsami.6b04587. Epub 2016 Jun 28.
Porous metal oxide architectures coated with a thin layer of carbon are attractive materials for energy storage applications. Here, a series of porous metal oxide (e.g., vanadium oxides, molybdenum oxides, manganese oxides) foams with/without nitrogen-doped carbon (N-C) coating have been synthesized via a general surfactant-assisted template method, involving the formation of porous metal oxides coated with 1-hexadecylamine (HDA) and a subsequent thermal treatment. The presence of HDA is of importance for the formation of a porous structure, and the successive pyrolysis of such a nitrogen-containing surfactant generates nitrogen-doped carbon (N-C) coated on the surface of metal oxides, which also provides a facile way to adjust the valence states of metal oxides via the carbothermal reduction reaction. When used as electrode materials, the highly porous metal oxides with N-C coating exhibited enhanced performance for lithium ion storage, thanks to the unique 3D structures associated with highly porous structure and thin N-C coating. Typically, the porous metal oxides (V2O5, MoO3, MnO2) exhibited discharge capacities of 286, 303, and 463 mAh g(-1) at current densities of 30 and 100 mA g(-1), respectively. In contrast, the metal oxides with low valences and carbon coating (VO2@N-C, MoO2@N-C, and MnO@N-C) exhibited improved capacities of 461, 613, and 892 mAh g(-1). The capacity retentions of about 87.5, 80.2, and 85.0% for VO2@N-C, MoO2@N-C, and MnO@N-C were achieved after 600 cycles, suggesting the acceptable cycling stability. The present strategy would provide general guidance for preparing porous metal oxide foams with enhanced lithium storage performances.
多孔金属氧化物结构，其表面覆盖有一层薄的碳，是储能应用中极具吸引力的材料。在这里，我们通过一种通用的表面活性剂辅助模板方法，合成了一系列具有/不具有氮掺杂碳（N-C）涂层的多孔金属氧化物（例如，钒氧化物、钼氧化物、锰氧化物）泡沫体，涉及到多孔金属氧化物的形成，该多孔金属氧化物首先被 1-十六烷基胺（HDA）覆盖，然后进行后续的热处理。HDA 的存在对于形成多孔结构很重要，并且这种含氮表面活性剂的连续热解会在金属氧化物表面生成氮掺杂碳（N-C）涂层，这也为通过碳热还原反应来调整金属氧化物的价态提供了一种简便的方法。将高度多孔的金属氧化物与 N-C 涂层用作电极材料时，由于与高度多孔结构和薄 N-C 涂层相关的独特 3D 结构，其锂离子存储性能得到了增强。通常，多孔金属氧化物（V2O5、MoO3、MnO2）在 30 和 100 mA g-1 的电流密度下的放电容量分别为 286、303 和 463 mAh g-1。相比之下，具有低化合价和碳涂层的金属氧化物（VO2@N-C、MoO2@N-C 和 MnO@N-C）表现出了更高的容量，分别为 461、613 和 892 mAh g-1。经过 600 次循环后，VO2@N-C、MoO2@N-C 和 MnO@N-C 的容量保持率约为 87.5%、80.2%和 85.0%，表明其具有可接受的循环稳定性。本策略为制备具有增强的锂离子存储性能的多孔金属氧化物泡沫体提供了一般性的指导。
