X-ray photoelectron spectroscopy and its applications in secondary batteries

As an important surface analysis technique based on the photoelectric effect, X-ray Photoelectron Spectroscopy (XPS) enables both qualitative and semiquantitative analysis of the elemental composition and chemical state of the solid material surface, and has thus been widely applied in secondary batteries. In this chapter, we first delve into a detailed introduction of the working principle, main functions, analytical capabilities and technical features of XPS. Following this, we outline various types of XPS spectral peaks and elucidate general principles for data analysis. Then, the preparation of diverse XPS specimens along with their packaging and transfer processes are introduced. Last but not least, we comprehensively summarize and discuss the application of XPS in secondary batteries, including the characterization of electrode material composition, charge/discharge mechanism, solid electrolyte interphase (SEI) structure, etc. Additionally, we provide examples of the insightful information acquired through XPS and demonstrate how this data aids researchers in achieving a more profound understanding of secondary batteries, which highlights the increasingly important role of XPS in the development of secondary batteries.