In situ characterizations for aqueous rechargeable zinc batteries

Recently, aqueous rechargeable zinc batteries (ARZBs) have become a hot topic in secondary batteries. Constant attention has witnessed the development of ARZBs, such as active materials, reaction mechanisms, and mass transport, and huge successes have been achieved. However, as the fundamental basis of battery monitoring in real-time and the theories of ARZBs, the in situ characterization techniques are equally worth discussing but the relevant review remains missing. Herein, this review focuses on the in situ characterization techniques of visualization and spectroscopy characterizations for ARZBs. Typical research of the in situ techniques is comprehensively discussed, including the setup of the in situ cells, the working principle of characterizations, the application, and the analysis applied in ARZBs. With the help of in situ characterizations, the reaction dynamics, transport kinetics, and thermodynamics in ARZBs can be thoroughly researched. Finally, the current primary challenges and future opportunities faced by in situ techniques toward ARZBs are also summarized. This review focuses on the in situ characterizations applied in aqueous rechargeable zinc batteries (ARZBs) from visualization technologies to spectroscopic techniques, which include 2D and 3D visualizations, optical spectroscopy, X-ray spectroscopy, and mass spectroscopy. The different applications of these in situ technologies in ARZBs to investigate the interphase evolutions and structural changes are discussed on an atom-level and nano-to-micro scale.image