Hao Junnan, Zhang Jian, Xia Guanglin, Liu Yajie, Zheng Yang, Zhang Wenchao, Tang Yongbing, Pang Wei Kong, Guo Zaiping
Institute for Superconducting and Electronic Materials, School of Mechanical, Materials, and Mechatronics Engineering , University of Wollongong , Wollongong , New South Wales 2522 , Australia.
College of Automotive and Mechanical Engineering , Changsha University of Science and Technology , Changsha 410114 , China.
ACS Nano. 2018 Oct 23;12(10):10430-10438. doi: 10.1021/acsnano.8b06020. Epub 2018 Sep 28.
Recently, heterostructures have attracted much attention in widespread research fields. By tailoring the physicochemical properties of the two components, creating heterostructures endows composites with diverse functions due to the synergistic effects and interfacial interaction. Here, a simple in situ localized phase transformation method is proposed to transform the transition-metal oxide electrode materials into heterostructures. Taking molybdenum oxide as an example, quasi-core-shell MoO@MoO heterostructures were successfully fabricated, which were uniformly anchored on reduced graphene oxide (rGO) for high-rate and highly durable lithium ion storage. The in situ introduction of the MoO shell not only effectively enhances the electronic conductivity but also creates MoO@MoO heterojunctions with abundant oxygen vacancies, which induces an inbuilt driving force at the interface, enhancing ion/electron transfer. In operando synchrotron X-ray powder diffraction has confirmed the excellent phase reversibility of the MoO shell during charge/discharge cycling, which contributes to the excellent cycling stability of the MoO@MoO/rGO electrode (1208.9 mAh g remaining at 5 A g after 2000 cycles). This simple in situ heterostructure fabrication method provides a facile way to optimize electrode materials for high-performance lithium ion batteries and possibly other energy storage devices.
近年来，异质结构在广泛的研究领域中备受关注。通过调整两种组分的物理化学性质，构建异质结构可使复合材料因协同效应和界面相互作用而具备多种功能。在此，我们提出一种简单的原位局部相变方法，将过渡金属氧化物电极材料转变为异质结构。以氧化钼为例，成功制备了准核壳结构的MoO@MoO异质结构，其均匀锚定在还原氧化石墨烯（rGO）上，用于高速率、高耐久性的锂离子存储。MoO壳层的原位引入不仅有效提高了电子导电性，还形成了具有大量氧空位的MoO@MoO异质结，在界面处诱导出内建驱动力，增强了离子/电子传输。原位同步辐射X射线粉末衍射证实了MoO壳层在充放电循环过程中具有优异的相可逆性，这有助于MoO@MoO/rGO电极具有出色的循环稳定性（2000次循环后，在5 A g电流下剩余容量为1208.9 mAh g）。这种简单的原位异质结构制备方法为优化高性能锂离子电池及其他可能的储能器件的电极材料提供了一种简便途径。
