| 초록 |
Phase transition behaviors of electrode materials for rechargeable batteries upon electrochemical cycling is generally considered to be an important feature for understanding the relationship between crystal structures and electrode performances of materials. Synchrotron diffraction technique provides fast and high resolution data collection to trace structure changes of crystalline materials with short time-scales, therefore it has been widely applied to battery research in recent years. In particular, in situ synchrotron X-ray diffraction technique allows accurate and efficient information about phase transition of crystalline electrode materials during dynamic charge/discharge process of battery cells. Here we have synthesized several positive electrode candidates for sodium-ion batteries; P2-, O3-layered oxides and mixed-anion phosphates, and their electrode performances have been investigated by Na-half cells. Through in situ synchrotron X-ray diffraction analysis during battery operation, phase transition models upon electrochemical desodiation/sodiation for each material have been proposed. Crystal structure, phase stability, and electrochemical properties of these electrode materials are closely related, providing an efficient strategy to design high-performance electrode materials for Na-ion batteries. |
