Liu Shiqi, Zhang Xu, Yan Pengfei, Cheng Renfei, Tang Yushu, Cui Min, Wang Boya, Zhang Liqiang, Wang Xiaohui, Jiang Yuyuan, Wang Lin, Yu Haijun
College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Education Ministry of China , Beijing University of Technology , Beijing 100124 , People's Republic of China.
Institute of Microstructure and Properties of Advanced Materials , Beijing University of Technology , No. 100, Pingleyuan, Chaoyang District , Beijing 100124 , People's Republic of China.
ACS Nano. 2019 Aug 27;13(8):8854-8864. doi: 10.1021/acsnano.9b02129. Epub 2019 Jul 25.
The development of silicon-based anode materials is important for improving the energy density of current lithium ion batteries. However, there are still strong demands for these materials with better cycle stability and higher reversible capacity. Here, a kind of dual bond restricted MXene-Si-CNT composite anode materials with enhanced electrochemical performance is reported. These dual bonds have been clearly revealed by an X-ray photoelectron spectroscopy technique and also proven by theoretical calculations with spontaneous reaction energy values (-0.190 and -0.429 eV/atom for Ti-Si and C-Si bonds, respectively). The cycle stability of the composites, prepared by a facile ball-milling synthetic method, can obviously be improved because of the existence of these dual bonds and the multidimensional constructed architecture. The MXene-Si-CNT composite with 60 wt % silicon possesses the best overall performance, with ∼80% capacity retention after 200 cycles, and achieves 841 mAh g at 2 A g. This approach demonstrates a promising strategy to exploit high-performance anode materials and lessens the immanent negative effect of silicon-based materials. Furthermore, it is significant to extend this method to other anode materials with serious volumetric change problems during the cycling process.
硅基负极材料的发展对于提高当前锂离子电池的能量密度至关重要。然而，对于具有更好循环稳定性和更高可逆容量的这些材料仍有强烈需求。在此，报道了一种具有增强电化学性能的双键受限MXene-Si-CNT复合负极材料。这些双键已通过X射线光电子能谱技术清晰揭示，并通过具有自发反应能值（Ti-Si键和C-Si键分别为-0.190和-0.429 eV/原子）的理论计算得到证实。通过简便的球磨合成方法制备的复合材料的循环稳定性，由于这些双键的存在和多维构建结构而能够明显提高。含60 wt%硅的MXene-Si-CNT复合材料具有最佳的整体性能，在200次循环后容量保持率约为80%，在2 A g下实现了841 mAh g的比容量。这种方法展示了一种开发高性能负极材料的有前景的策略，并减轻了硅基材料固有的负面影响。此外，将这种方法扩展到在循环过程中存在严重体积变化问题的其他负极材料具有重要意义。
