In situ techniques for Li-rechargeable battery analysis

Reducing our carbon footprint is one of the most pressing issues facing humanity today. The technology of Li-rechargeable batteries is permeating every corner of our lives as a result of our efforts to reduce the use of carbon energy. Batteries can be seen metaphorically as “living cells”, and approaching the future of that technology requires observing and understanding the real-time phenomena that occur inside battery systems during (electro)chemical reactions. In this regard, in situ analysis techniques have made significant progress toward understanding the basic science of battery systems and finding better performance-improving factors. There are various analysis methods utilizing electromagnetic waves, electrons, and neutrons to perform multifaceted analyses of battery systems from the atomic to the macroscopic scale. Now is the opportune moment to construct a comprehensive guide that facilitates the design of advanced Li-rechargeable battery systems, adopting a highly discerning and all-encompassing approach toward these cutting-edge technologies. In this review article, we discuss and organize the key components such as capabilities, limitations, and practical tips with a comprehensive perspective on various in situ techniques. Moreover, this article covers a wide range of information from the nano to the micrometer scale, such as electronic, atomic, crystal, and morphological structures, from stereoscopic perspectives considering the probing depth.