Operando X‐ray Diffraction Characterization for Understanding the Intrinsic Electrochemical Mechanism in Rechargeable Battery Materials

Studying and understanding the physical and chemical changes in electrode materials during cycling is important for achieving high‐performance rechargeable batteries. Operando X‐ray diffraction (XRD), as an efficient analytic method, has been developed to probe the phase transitions and crystal‐structure changes in electrodes. Recent progress in studying the electrochemical reaction process of electrodes during cycling by the operando XRD analysis method is summarized. The applications of operando XRD toward both cathode and anode materials of rechargeable batteries are summarized, including polyanionic compounds, layered oxides, and insertion‐, conversion‐ and alloying‐type anodes. The correlation between the structure changes and electrochemical performance of electrode materials is systematically analyzed. Finally, the challenges and perspectives on the development of the operando XRD characterization method in electrode materials are introduced and discussed.