Batteries store energy via chemical reactions for later use in electronics, transportation, and grid load leveling. Most commercial rechargeable batteries are based on mechanisms fairly well understood. To move forward in the development of better energy materials, new materials need to be developed to increase efficiency and lifetime of batteries. Tracking the structural changes, as a function of battery cycling, reveals the molecular mechanism used by the material for charge storage. Analyzing the structure and behavior of known battery materials provides important information for designing new crystal structures for cathode and anode materials, key components to a battery’s functionality.

Synchrotron-based techniques such as x-ray absorption spectroscopy (XAS) and x-ray diffraction (XRD) are invaluable tools to study molecules, materials, and systems relevant to electrochemical energy storage since they can provide structural and compositional information under realistic operating conditions. A specially designed coin cell battery allows for the operando investigation of structural, compositional, and chemical changes within the battery as a function of the state of charge. Very thin material layers can be study using grazing-incidence techniques to look at wide and small angle diffraction to determine structures of difference size scales. These studies, called GISAXS and GIWAXS, provide fundamental insights in the processing of materials for organic photovoltaics such as bulk heterojunctions or organic perovskite based solar cells.