科研之友
微信
新浪微博
Facebook
分享链接
摘要
As rechargeable lithium-ion batteries (LIBs) develop unprecedentedly faster than ever before, it needs urgently to search for a new and careful design of anode materials, which can boost the battery performance substantially, particularly the rate capability, in order to realize fast charge and discharge in the practical applications of high-energy devices. On that account, heterostructures with the excellent interface effects and the formation of built in potential at the hetero-interface have emerged as a promising solution to address the above issue. In this paper, we prepared SnSe/SnO2@Gr heterostructure composite, in which the SnO2 nanospheres are homogeneously dispersed and wrapped into the Graphene matrix, interconnecting to form a three dimensional (3D) hierarchical architecture, followed by the selenium treatment to obtain SnSe/SnO2 heterostructure. This distinctive nanoarchitecture can enhance charge transfer and lithium-ions diffusion, as well as improving specific conductivity and charge/discharge capability of SnSe/SnO2@Gr heterostructure. When used as anode material for lithium ion batteries, SnSe/SnO2@Gr shows a higher rate capability than SnO2@Gr and SnO2. Moreover, after 200 cycles, the storage capacity of SnSe/SnO2@Gr is still up to 810 mAh/g and almost remains unchanged, suggesting a high cyclability. It is noted that the enhanced electrochemical performance of SnSe/SnO2@ Gr can be attributed to the built-in electric field of heterojunction, which is proved by the DFT calculation and CI-NEB methods, illustrating that the existence of the built-in electric field adds an additional electromotive force (E) to boost the electron mobility of the active material. Noteworthy, the results show that the large difference of the work function of the two semiconductor materials could lead to the high additional potential (phi E), which surly be the beneficial for improving the performance of the battery.
- 出版日期2018-9-1
- 单位西北大学
