In-situ characterization

During battery charge/discharge, various physical and chemical processes usually occur in the electrode material, such as volume changes, structural and electronic transitions and structural degradation. These processes significantly influence the electrochemical behavior and therefore have to be studied in detail to maintain or improve the battery performance.

Operando X-ray diffraction (XRD) and Operando X-ray absorption spectroscopy (XAS) are efficient and complementary analytical methods which allow to understand physical and chemical changes in electrode materials during battery operation.

At the EBZ Dresden a detailed characterization of novel silicon anodes and oxide cathodes will be performed using Operando-XRD and XAS. The aim is to understand the underlying redox and degradation mechanisms and to develop new materials with increased energy density and cycle stability.

One of the main issues is to understand the chemical and electrochemical reactions at the interface between the electrode and the electrolyte in order to develop strategies for safe operation and a high number of charge cycles. In addition to various in situ characterization methods, Raman spectroscopy is a non-destructive and often used method to analyze the relationships between the structural and electrochemical behavior of the electrode materials, the electrode-electrolyte interface and the electrolyte.

In this project, NaMLab provides its expertise in the fabrication of high capacity anode structures based on silicon nanowires and investigates them with Raman spectroscopy. Raman spectroscopy allows to conclude about structural and electrochemical changes in the accumulator components. Using in situ Raman spectroscopy, the battery components are analyzed for changes in order to characterize the electrode-electrolyte interface during charging and discharging. Thereby allowing a better understanding of the degradation mechanisms.