Liu Wenyi, Huang Haoliang, Jiang Zhongyuan, Wang Jianlin, Yang Yuanjun, Chen Zezhi, Liu Huan, Huang Qiuping, Peng Ranran, Fu Zhengping, Lu Yalin
Anhui Laboratory of Advanced Photon Science and Technology, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei 230026, P. R. China.
ACS Appl Mater Interfaces. 2020 Oct 14;12(41):47010-47017. doi: 10.1021/acsami.0c13532. Epub 2020 Oct 6.
The electrochemical performance of supercapacitors is suppressed by a large number of defects in the interface of heterostructure due to lattice mismatch. In this paper, the (001) oriented rutile MnO thin films with different thicknesses were grown on rutile TiO substrates. The lattice mismatch between film and substrate was minimized through a Ti diffusion self-adapting layer. The energy-dispersive spectroscopy mappings were used to measure the diffusion range of Ti. The results of high-resolution X-ray diffraction confirmed that the dependence of the out-of-plane lattice parameter on the thickness was consistent with the self-adapting interface model, indicating that Ti diffusion can indeed alleviate the lattice mismatch. In addition, the results of the synchrotron soft X-ray absorption spectrum indicated that the capacitance of the thin films with a large proportion of Ti diffusion increased with electrons involved in the reaction. Although the decrease of carrier density and conductivity of the thinner films depressed the electrochemical activity, it is worth mentioning that the film we designed still has considerable specific capacitance even when it is very thin, which can provide a new idea for the development of thinner and larger capacity potential micro-supercapacitors.
由于晶格失配，异质结构界面处的大量缺陷会抑制超级电容器的电化学性能。本文在金红石型TiO衬底上生长了不同厚度的（001）取向金红石型MnO薄膜。通过Ti扩散自适应层使薄膜与衬底之间的晶格失配最小化。利用能量色散光谱映射来测量Ti的扩散范围。高分辨率X射线衍射结果证实，面外晶格参数对厚度的依赖性与自适应界面模型一致，表明Ti扩散确实可以缓解晶格失配。此外，同步加速器软X射线吸收光谱结果表明，Ti扩散比例较大的薄膜的电容随着参与反应的电子数增加而增大。尽管较薄薄膜的载流子密度和电导率降低抑制了其电化学活性，但值得一提的是，我们设计的薄膜即使非常薄仍具有相当可观的比电容，这可为开发更薄、容量潜力更大的微型超级电容器提供新思路。
