Owing to low cost and natural abundance of sodium reserves, sodium-ion batteries (SIBs) are attracting increasing attention and become promising alternatives to lithium ion batteries (LIBs). Based on merits of high structure stability and superb conductivity, nanocomposites have been widely investigated for SIB electrodes. However, SIBs still face some significant issues like serious side reactions, low energy density, and poor cycling life. Further improvement of the electrochemical performance needs definitely a deep understanding of structural and kinetic process occurred in these nanocomposite electrodes during charging/discharging processes. Recently, a diversity of in-situ techniques has emerged to investigate the inner phenomena occurred. In this short review, we summarize the state-of-the-art in-situ techniques, including in-situ transmission electron microscopy (TEM), in-situ X-ray diffraction (XRD), in-situ X-ray absorption spectroscopy (XAS), and in-situ Raman spectroscopy, applied to the characterization of morphological evolutions, mechanical/chemical changes, and phase transitions of these nanocomposite electrodes during electrochemical sodiation/de-sodiation processes. Finally, we also discuss limitations and future opportunities of in-situ technologies in nanocomposite materials for SIBs. The review aims at better understanding of these in-situ techniques for researchers in the society of SIBs, and is expected to provide guidance of nanocomposites for other fields.

由于低成本和钠储量自然丰富，钠离子电池（SIB）引起了越来越多的关注，并成为锂离子电池（LIB）的有前途的替代品。基于高结构稳定性和极好的电导率的优点，已广泛研究了用于SIB电极的纳米复合材料。但是，SIB仍然面临一些重大问题，例如严重的副反应，低能量密度和较差的循环寿命。电化学性能的进一步提高无疑需要深入了解在充电/放电过程中这些纳米复合电极中发生的结构和动力学过程。最近，出现了多种现场技术来研究发生的内部现象。在这篇简短的评论中，我们总结了最先进的现场技术，包括现场技术透射电子显微镜（TEM），原位X射线衍射（XRD），原位X射线吸收光谱（XAS）和原位拉曼光谱，用于表征形态演化，机械/化学变化，这些纳米复合电极在电化学的增盐/脱盐过程中的相变和相变。最后，我们还讨论了用于SIB的纳米复合材料中原位技术的局限性和未来的机会。该综述旨在为SIB社会的研究人员更好地理解这些原位技术，并有望为其他领域的纳米复合材料提供指导。